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If not, you may need to add the pre-RFC5378 disclaimer. (See the Legal Provisions document at https://trustee.ietf.org/license-info for more information.) -- The document date (June 6, 2008) is 5796 days in the past. Is this intentional? Checking references for intended status: Proposed Standard ---------------------------------------------------------------------------- (See RFCs 3967 and 4897 for information about using normative references to lower-maturity documents in RFCs) ** Downref: Normative reference to an Informational RFC: RFC 5148 ** Obsolete normative reference: RFC 2434 (Obsoleted by RFC 5226) Summary: 3 errors (**), 0 flaws (~~), 7 warnings (==), 7 comments (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Mobile Ad hoc Networking (MANET) T. Clausen 3 Internet-Draft LIX, Ecole Polytechnique, France 4 Intended status: Standards Track C. Dearlove 5 Expires: December 8, 2008 BAE Systems Advanced Technology 6 Centre 7 P. Jacquet 8 Project Hipercom, INRIA 9 The OLSRv2 Design Team 10 MANET Working Group 11 June 6, 2008 13 The Optimized Link State Routing Protocol version 2 14 draft-ietf-manet-olsrv2-06 16 Status of This Memo 18 By submitting this Internet-Draft, each author represents that any 19 applicable patent or other IPR claims of which he or she is aware 20 have been or will be disclosed, and any of which he or she becomes 21 aware will be disclosed, in accordance with Section 6 of BCP 79. 23 Internet-Drafts are working documents of the Internet Engineering 24 Task Force (IETF), its areas, and its working groups. Note that 25 other groups may also distribute working documents as Internet- 26 Drafts. 28 Internet-Drafts are draft documents valid for a maximum of six months 29 and may be updated, replaced, or obsoleted by other documents at any 30 time. It is inappropriate to use Internet-Drafts as reference 31 material or to cite them other than as "work in progress." 33 The list of current Internet-Drafts can be accessed at 34 http://www.ietf.org/ietf/1id-abstracts.txt. 36 The list of Internet-Draft Shadow Directories can be accessed at 37 http://www.ietf.org/shadow.html. 39 This Internet-Draft will expire on December 8, 2008. 41 Abstract 43 This document describes version 2 of the Optimized Link State Routing 44 (OLSRv2) protocol. The protocol embodies an optimization of the 45 classical link state algorithm tailored to the requirements of a 46 Mobile Ad hoc NETwork (MANET). 48 The key optimization in OLSRv2 is that of multipoint relays (MPRs), 49 providing an efficient mechanism for network-wide broadcast of link 50 state information (i.e. reducing the cost of performing a network- 51 wide link state broadcast). A secondary optimization is that OLSRv2 52 employs partial link state information; each node maintains 53 information about all destinations, but only a subset of links. 54 Consequently, only selected nodes flood link state advertisements 55 (thus reducing the number of network-wide link state broadcasts) and 56 these advertisements contain only a subset of links (thus reducing 57 the size of network-wide link state broadcasts). The partial link 58 state information thus obtained still allows each OLSRv2 node to at 59 all times maintain optimal (in terms of number of hops) routes to all 60 destinations in the network. 62 OLSRv2 imposes minimum requirements on the network by not requiring 63 sequenced or reliable transmission of control traffic. Furthermore, 64 the only interaction between OLSRv2 and the IP stack is routing table 65 management. 67 OLSRv2 is particularly suitable for large and dense networks as the 68 technique of MPRs works best in this context. 70 Table of Contents 72 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 5 73 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 6 74 3. Applicability Statement . . . . . . . . . . . . . . . . . . . 8 75 4. Protocol Overview and Functioning . . . . . . . . . . . . . . 10 76 5. Protocol Parameters and Constants . . . . . . . . . . . . . . 13 77 5.1. Local History Times . . . . . . . . . . . . . . . . . . . 13 78 5.2. Message Intervals . . . . . . . . . . . . . . . . . . . . 14 79 5.3. Advertised Information Validity Times . . . . . . . . . . 14 80 5.4. Received Message Validity Times . . . . . . . . . . . . . 15 81 5.5. Jitter . . . . . . . . . . . . . . . . . . . . . . . . . . 16 82 5.6. Hop Limit Parameter . . . . . . . . . . . . . . . . . . . 16 83 5.7. Willingness . . . . . . . . . . . . . . . . . . . . . . . 17 84 5.8. Parameter Change Constraints . . . . . . . . . . . . . . . 17 85 6. Information Bases . . . . . . . . . . . . . . . . . . . . . . 19 86 6.1. Local Information Base . . . . . . . . . . . . . . . . . . 19 87 6.1.1. Originator Set . . . . . . . . . . . . . . . . . . . . 19 88 6.1.2. Local Attached Network Set . . . . . . . . . . . . . . 20 90 6.2. Node Information Base . . . . . . . . . . . . . . . . . . 20 91 6.3. Topology Information Base . . . . . . . . . . . . . . . . 21 92 6.3.1. Advertised Neighbor Set . . . . . . . . . . . . . . . 21 93 6.3.2. Advertising Remote Node Set . . . . . . . . . . . . . 21 94 6.3.3. Topology Set . . . . . . . . . . . . . . . . . . . . . 22 95 6.3.4. Attached Network Set . . . . . . . . . . . . . . . . . 22 96 6.3.5. Routing Set . . . . . . . . . . . . . . . . . . . . . 23 97 6.4. Processing and Forwarding Information Base . . . . . . . . 23 98 6.4.1. Received Set . . . . . . . . . . . . . . . . . . . . . 24 99 6.4.2. Processed Set . . . . . . . . . . . . . . . . . . . . 24 100 6.4.3. Forwarded Set . . . . . . . . . . . . . . . . . . . . 24 101 6.4.4. Relay Set . . . . . . . . . . . . . . . . . . . . . . 25 102 7. Packet Processing and Message Forwarding . . . . . . . . . . . 26 103 7.1. Actions when Receiving an OLSRv2 Packet . . . . . . . . . 26 104 7.2. Actions when Receiving an OLSRv2 Message . . . . . . . . . 26 105 7.3. Message Considered for Processing . . . . . . . . . . . . 27 106 7.4. Message Considered for Forwarding . . . . . . . . . . . . 28 107 8. Packets and Messages . . . . . . . . . . . . . . . . . . . . . 31 108 8.1. HELLO Messages . . . . . . . . . . . . . . . . . . . . . . 31 109 8.1.1. HELLO Message TLVs . . . . . . . . . . . . . . . . . . 32 110 8.1.2. HELLO Message Address Block TLVs . . . . . . . . . . . 32 111 8.2. TC Messages . . . . . . . . . . . . . . . . . . . . . . . 32 112 8.2.1. TC Message TLVs . . . . . . . . . . . . . . . . . . . 34 113 8.2.2. TC Message Address Block TLVs . . . . . . . . . . . . 34 114 9. HELLO Message Generation . . . . . . . . . . . . . . . . . . . 35 115 9.1. HELLO Message: Transmission . . . . . . . . . . . . . . . 35 116 10. HELLO Message Processing . . . . . . . . . . . . . . . . . . . 36 117 10.1. Updating Willingness . . . . . . . . . . . . . . . . . . . 36 118 10.2. Updating MPR Selectors . . . . . . . . . . . . . . . . . . 36 119 10.3. Symmetric 1-Hop and 2-Hop Neighborhood Changes . . . . . . 36 120 11. TC Message Generation . . . . . . . . . . . . . . . . . . . . 38 121 11.1. TC Message: Transmission . . . . . . . . . . . . . . . . . 39 122 12. TC Message Processing . . . . . . . . . . . . . . . . . . . . 40 123 12.1. Initial TC Message Processing . . . . . . . . . . . . . . 40 124 12.1.1. Populating the Advertising Remote Node Set . . . . . . 41 125 12.1.2. Populating the Topology Set . . . . . . . . . . . . . 42 126 12.1.3. Populating the Attached Network Set . . . . . . . . . 42 127 12.2. Completing TC Message Processing . . . . . . . . . . . . . 43 128 12.2.1. Purging the Topology Set . . . . . . . . . . . . . . . 43 129 12.2.2. Purging the Attached Network Set . . . . . . . . . . . 43 130 13. Information Base Changes . . . . . . . . . . . . . . . . . . . 44 131 14. Selecting MPRs . . . . . . . . . . . . . . . . . . . . . . . . 45 132 15. Populating Derived Sets . . . . . . . . . . . . . . . . . . . 47 133 15.1. Populating the Relay Set . . . . . . . . . . . . . . . . . 47 134 15.2. Populating the Advertised Neighbor Set . . . . . . . . . . 47 135 16. Routing Set Calculation . . . . . . . . . . . . . . . . . . . 48 136 16.1. Network Topology Graph . . . . . . . . . . . . . . . . . . 48 137 16.2. Populating the Routing Set . . . . . . . . . . . . . . . . 49 138 16.3. Routing Set Updates . . . . . . . . . . . . . . . . . . . 50 139 17. Proposed Values for Parameters and Constants . . . . . . . . . 51 140 17.1. Local History Time Parameters . . . . . . . . . . . . . . 51 141 17.2. Message Interval Parameters . . . . . . . . . . . . . . . 51 142 17.3. Advertised Information Validity Time Parameters . . . . . 51 143 17.4. Received Message Validity Time Parameters . . . . . . . . 51 144 17.5. Jitter Time Parameters . . . . . . . . . . . . . . . . . . 51 145 17.6. Hop Limit Parameter . . . . . . . . . . . . . . . . . . . 51 146 17.7. Willingness Parameter and Constants . . . . . . . . . . . 52 147 18. Sequence Numbers . . . . . . . . . . . . . . . . . . . . . . . 53 148 19. Security Considerations . . . . . . . . . . . . . . . . . . . 54 149 19.1. Confidentiality . . . . . . . . . . . . . . . . . . . . . 54 150 19.2. Integrity . . . . . . . . . . . . . . . . . . . . . . . . 54 151 19.3. Interaction with External Routing Domains . . . . . . . . 55 152 20. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 57 153 20.1. Message Types . . . . . . . . . . . . . . . . . . . . . . 57 154 20.2. TLV Types . . . . . . . . . . . . . . . . . . . . . . . . 57 155 21. References . . . . . . . . . . . . . . . . . . . . . . . . . . 59 156 21.1. Normative References . . . . . . . . . . . . . . . . . . . 59 157 21.2. Informative References . . . . . . . . . . . . . . . . . . 59 158 Appendix A. Node Configuration . . . . . . . . . . . . . . . . . 61 159 Appendix B. Example Algorithm for Calculating MPRs . . . . . . . 62 160 B.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 62 161 B.2. MPR Selection Algorithm for each OLSRv2 Interface . . . . 63 162 Appendix C. Example Algorithm for Calculating the Routing Set . . 64 163 C.1. Add Local Symmetric Links . . . . . . . . . . . . . . . . 64 164 C.2. Add Remote Symmetric Links . . . . . . . . . . . . . . . . 65 165 C.3. Add Attached Networks . . . . . . . . . . . . . . . . . . 66 166 Appendix D. Example Message Layout . . . . . . . . . . . . . . . 67 167 Appendix E. Constraints . . . . . . . . . . . . . . . . . . . . . 69 168 Appendix F. Flow and Congestion Control . . . . . . . . . . . . . 73 169 Appendix G. Contributors . . . . . . . . . . . . . . . . . . . . 74 170 Appendix H. Acknowledgements . . . . . . . . . . . . . . . . . . 75 172 1. Introduction 174 The Optimized Link State Routing protocol version 2 (OLSRv2) is an 175 update to OLSRv1 as published in [RFC3626]. Compared to RFC3626, 176 OLSRv2 retains the same basic mechanisms and algorithms, while 177 providing a more flexible signaling framework and some simplification 178 of the messages being exchanged. Also, OLSRv2 accommodates either 179 IPv4 and IPv6 addresses in a compact manner. 181 OLSRv2 is developed for mobile ad hoc networks. It operates as a 182 table driven, proactive protocol, i.e. it exchanges topology 183 information with other nodes in the network regularly. Each node 184 selects a set of its neighbor nodes as "MultiPoint Relays" (MPRs). 185 Control traffic may be flooded through the network using hop by hop 186 forwarding, but where a node only needs to forward control traffic 187 directly received from its MPR selectors (nodes which have selected 188 it as an MPR). This mechanism, denoted "MPR flooding", provides an 189 efficient mechanism for information distribution within the MANET by 190 reducing the number of transmissions required. 192 Nodes selected as MPRs also have a special responsibility when 193 declaring link state information in the network. A sufficient 194 requirement for OLSRv2 to provide shortest (lowest hop count) path 195 routes to all destinations is that nodes declare link state 196 information for their MPR selectors, if any. Additional available 197 link state information may be transmitted, e.g. for redundancy. 198 Thus, as well as being used to facilitate MPR flooding, use of MPRs 199 allows the reduction of the number and size of link state messages, 200 and MPRs are used as intermediate nodes in multi-hop routes. 202 A node selects MPRs from among its one hop neighbors connected by 203 "symmetric", i.e. bi-directional, links. Therefore, selecting routes 204 through MPRs automatically avoids the problems associated with data 205 packet transfer over uni-directional links (such as the problem of 206 not getting link layer acknowledgments at each hop, for link layers 207 employing this technique). 209 OLSRv2 is developed to work independently from other protocols. 210 (Parts of OLSRv2 have been published separately as [packetbb], 211 [timetlv], [RFC5148] and [nhdp] for wider use.) Likewise, OLSRv2 212 makes no assumptions about the underlying link layer. However, 213 OLSRv2 may use link layer information and notifications when 214 available and applicable, as described in [nhdp]. 216 OLSRv2, as OLSRv1, inherits its concept of forwarding and relaying 217 from HIPERLAN (a MAC layer protocol) which is standardized by ETSI 218 [HIPERLAN], [HIPERLAN2]. 220 2. Terminology 222 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 223 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 224 document are to be interpreted as described in [RFC2119]. 226 MANET specific terminology is to be interpreted as described in 227 [packetbb] and [nhdp]. 229 Additionally, this document uses the following terminology: 231 Node - A MANET router which implements the Optimized Link State 232 Routing protocol version 2 as specified in this document. 234 OLSRv2 interface - A MANET interface, running OLSRv2. Note that all 235 references to MANET interfaces in [nhdp] refer to OLSRv2 236 interfaces when using [nhdp] as part of OLSRv2. 238 Address - An address, as recorded in the Information Bases specified 239 by this protocol, and included in HELLO and TC messages generated 240 by this protocol, may be either an address or an address prefix. 241 These can be represented as a single address object in a HELLO or 242 TC message, as defined by [packetbb]. An address so represented 243 is considered to have a prefix length equal to its length (in 244 bits) when considered as an address object, and a similar 245 convention is used in the Information Bases specified by this 246 protocol. Two addresses (address objects) are considered equal 247 only if their prefix lengths are also equal. 249 Willingness - The willingness of a node is a numerical value between 250 WILL_NEVER and WILL_ALWAYS (both inclusive), which represents the 251 node's willingness to be selected as an MPR. 253 Willing symmetric 1-hop neighbor - A symmetric 1-hop neighbor of 254 this node which has willingness not equal to WILL_NEVER. 256 Symmetric strict 2-hop neighbor - A symmetric 2-hop neighbor of this 257 node which is not a symmetric 1-hop neighbor of this node, and is 258 a symmetric 1-hop neighbor of a willing symmetric 1-hop neighbor 259 of this node. 261 Symmetric strict 2-hop neighbor through OLSRv2 interface I - A 262 symmetric strict 2-hop neighbor of this node which is a symmetric 263 1-hop neighbor of a willing symmetric 1-hop neighbor of this node 264 by a symmetric link including OLSRv2 interface I. This node MAY 265 elect to consider only information received over OLSRv2 interface 266 I in making this determination. 268 Symmetric strict 2-hop neighborhood - The set of the symmetric 269 strict 2-hop neighbors of a node. 271 Multipoint relay (MPR) - A node which is selected by its symmetric 272 1-hop neighbor, node X, to "re-transmit" all the broadcast 273 messages that it receives from node X, provided that the message 274 is not a duplicate, and that the hop limit field of the message is 275 greater than one. 277 MPR selector - A node which has selected its symmetric 1-hop 278 neighbor, node X, as one of its MPRs is an MPR selector of node X. 280 MPR flooding - The optimized MANET-wide information distribution 281 mechanism, employed by this protocol, in which a message is 282 relayed by only a reduced subset of the nodes in the network. 284 3. Applicability Statement 286 OLSRv2 is a proactive routing protocol for mobile ad hoc networks 287 (MANETs) [RFC2501]. The larger and more dense a network, the more 288 optimization can be achieved by using MPRs compared to the classic 289 link state algorithm. OLSRv2 enables hop-by-hop routing, i.e. each 290 node using its local information provided by OLSRv2 to route packets. 292 As OLSRv2 continuously maintains routes to all destinations in the 293 network, the protocol is beneficial for traffic patterns where the 294 traffic is random and sporadic between a large subset of nodes, and 295 where the (source, destination) pairs are changing over time. No 296 additional control traffic need be generated in this case since 297 routes are maintained for all known destinations at all times. Also, 298 since routes are maintained continuously, traffic is subject to no 299 delays due to buffering or to route discovery. 301 OLSRv2 supports nodes which have multiple interfaces which 302 participate in the MANET using OLSRv2. As described in [nhdp], each 303 OLSRv2 interface may have one or more network addresses (which may 304 have prefix lengths). OLSRv2, additionally, supports nodes which 305 have non-OLSRv2 interfaces which may be local or can serve as 306 gateways towards other networks. 308 OLSRv2 uses the format specified in [packetbb] for all messages and 309 packets. OLSRv2 is thereby able to allow for extensions via 310 "external" and "internal" extensibility. External extensibility 311 allows a protocol extension to specify and exchange new message 312 types, which can be forwarded and delivered correctly even by nodes 313 which do not support that extension. Internal extensibility allows a 314 protocol extension to define additional attributes to be carried 315 embedded in the standard OLSRv2 control messages detailed in this 316 specification (or any new message types defined by other protocol 317 extensions) using the TLV mechanism specified in [packetbb], while 318 still allowing nodes not supporting that extension to forward 319 messages including the extension, and to process messages ignoring 320 the extension. 322 The OLSRv2 neighborhood discovery protocol using HELLO messages is 323 specified in [nhdp]. This neighborhood discovery protocol serves to 324 ensure that each OLSRv2 node has available continuously updated 325 Information Bases describing the node's 1-hop and symmetric 2-hop 326 neighbors. This neighborhood discovery protocol, which also uses 327 [packetbb], is extended in this document by the addition of MPR 328 information. 330 OLSRv2 does not make any assumption about node addresses, other than 331 that each node is assumed to have at least one unique and routable IP 332 address for each interface that it has which participates in the 333 MANET. 335 4. Protocol Overview and Functioning 337 OLSRv2 is a proactive routing protocol for mobile ad hoc networks. 338 The protocol inherits the stability of a link state algorithm and has 339 the advantage of having routes immediately available when needed due 340 to its proactive nature. OLSRv2 is an optimization of the classical 341 link state protocol, tailored for mobile ad hoc networks. The main 342 tailoring and optimizations of OLSRv2 are: 344 o Unacknowledged transmission of all control messages; control 345 messages are sent periodically, but may also be sent in response 346 to changes in the local neighborhood. 348 o MPR flooding for MANET-wide link state information distribution. 350 o Partial topology maintenance - each node knows only a subset of 351 the links in the network, sufficient for a minimum hop route to 352 all destinations. 354 The MPR flooding and partial topology maintenance are based on the 355 concept of MultiPoint Relays (MPRs), selected independently by nodes 356 based on the symmetric 1-hop and 2-hop neighbor information 357 maintained using [nhdp]. 359 Using the message exchange format [packetbb] and the neighborhood 360 discovery protocol [nhdp], OLSRv2 also contains the following main 361 components: 363 o A TLV, to be included within the HELLO messages of [nhdp], 364 allowing a node to signal MPR selection. 366 o The optimized mechanism for MANET-wide information distribution, 367 denoted "MPR flooding". 369 o A specification of MANET-wide signaling, denoted TC (Topology 370 Control) messages. TC messages in OLSRv2 serve to: 372 * inject link state information into the entire MANET; 374 * inject addresses of hosts and networks for which they may serve 375 as a gateway into the entire network. 377 TC messages are emitted periodically, thereby allowing nodes to 378 continuously track changes in the network. Incomplete TC messages 379 may be used to report additions to advertised information without 380 repeating unchanged information. Some TC messages may be MPR 381 flooded over only part of the network, allowing a node to ensure 382 that nearer nodes are kept more up to date than distant nodes, 383 such as is used in Fisheye State Routing [FSR] and Fuzzy Sighted 384 Link State routing [FSLS]. 386 Each node in the network selects a set of MPRs. The MPRs of a node X 387 may be any subset of node X's willing symmetric 1-hop neighbors, such 388 that every node in the symmetric strict 2-hop neighborhood of node X 389 has a symmetric link to at least one of node X's MPRs. The MPRs of a 390 node may thus be said to "cover" the node's symmetric strict 2-hop 391 neighborhood. Each node also maintains information about the set of 392 symmetric 1-hop neighbors that have selected it as an MPR, its MPR 393 selectors. 395 As long as the condition above is satisfied, any algorithm selecting 396 MPRs is acceptable in terms of implementation interoperability. 397 However if smaller sets of MPRs are selected then the greater the 398 efficiency gains that are possible. An analysis and examples of MPR 399 selection algorithms is given in [MPR]. 401 A node may independently determine and advertise its willingness to 402 be selected as an MPR. A node may advertise that it always should be 403 selected as an MPR or that it should never be selected as an MPR. In 404 the latter case, the node will neither relay control messages, nor 405 will that node be included as an intermediate node in any routing 406 table calculations. Use of variable willingness is most effective in 407 dense networks. 409 In OLSRv2, actual efficiency gains are based on the sizes of each 410 node's Relay Set, the set of symmetric 1-hop neighbors for which it 411 is to relay broadcast traffic, and its Advertised Neighbor Set, the 412 set of symmetric 1-hop neighbors for which it is to advertise link 413 state information into the network in TC messages. Each of these 414 sets MUST contain all MPR selectors, and MAY contain additional 415 nodes. If the Advertised Neighbor Set is empty, TC messages are not 416 generated by that node, unless needed for gateway reporting, or for a 417 short period to accelerate the removal of outdated link state 418 information. 420 OLSRv2 is designed to work in a completely distributed manner and 421 does not depend on any central entity. The protocol does not require 422 reliable transmission of control messages; each node sends control 423 messages periodically, and can therefore sustain a reasonable loss of 424 some such messages. Such losses may occur frequently in radio 425 networks due to collisions or other transmission problems. OLSRv2 426 MAY use "jitter", randomized adjustments to message transmission 427 times, to reduce the incidence of collisions [RFC5148]. 429 OLSRv2 does not require sequenced delivery of messages. Each TC 430 message contains a sequence number which is incremented for each 431 message. Thus the recipient of a TC message can, if required, easily 432 identify which information is more recent - even if messages have 433 been re-ordered while in transmission. 435 OLSRv2 only interacts with IP through routing table management. 436 OLSRv2 sends its control messages as described in [packetbb] and 437 [nhdp]. 439 5. Protocol Parameters and Constants 441 The parameters and constants used in this specification are those 442 defined in [nhdp] plus those defined in this section. The separation 443 in [nhdp] into interface parameters, node parameters and constants is 444 also used in OLSRv2, however all but one (RX_HOLD_TIME) of the 445 parameters added by OLSRv2 are node parameters. Parameters may be 446 classified into the following categories: 448 o Local history times 450 o Message intervals 452 o Advertised information validity times 454 o Received message validity times 456 o Jitter times 458 o Hop limits 460 o Willingness 462 In addition, constants for particular cases of a node's willingness 463 to be an MPR are defined. These parameters and constants are 464 detailed in the following sections. As for the parameters in [nhdp], 465 parameters defined in this document may be changed dynamically by a 466 node, and need not be the same on different nodes, even in the same 467 MANET, or on different interfaces of the same node (for interface 468 parameters). 470 5.1. Local History Times 472 The following parameter manages the time for which local information 473 is retained: 475 O_HOLD_TIME - is used to define the time for which a recently used 476 and replaced originator address is used to recognize the node's 477 own messages. 479 The following constraint applies to this parameter: 481 o O_HOLD_TIME >= 0 483 5.2. Message Intervals 485 The following interface parameters regulate TC message transmissions 486 by a node. TC messages are usually sent periodically, but MAY also 487 be sent in response to changes in the node's Advertised Neighbor Set 488 and Local Attached Network Set. With a larger value of the parameter 489 TC_INTERVAL, and a smaller value of the parameter TC_MIN_INTERVAL, TC 490 messages may more often be transmitted in response to changes in a 491 highly dynamic network. However because a node has no knowledge of, 492 for example, nodes remote to it joining the network, TC messages MUST 493 NOT be sent purely responsively. 495 TC_INTERVAL - is the maximum time between the transmission of two 496 successive TC messages by this node. When no TC messages are sent 497 in response to local network changes (by design, or because the 498 local network is not changing) then TC messages SHOULD be sent at 499 a regular interval TC_INTERVAL, possibly modified by jitter as 500 specified in [RFC5148]. 502 TC_MIN_INTERVAL - is the minimum interval between transmission of 503 two successive TC messages by this node. (This minimum interval 504 MAY be modified by jitter, as specified in [RFC5148].) 506 The following constraints apply to these parameters: 508 o TC_INTERVAL > 0 510 o TC_MIN_INTERVAL >= 0 512 o TC_INTERVAL >= TC_MIN_INTERVAL 514 o If INTERVAL_TIME TLVs as defined in [timetlv] are included in TC 515 messages, then TC_INTERVAL MUST be representable as described in 516 [timetlv]. 518 5.3. Advertised Information Validity Times 520 The following parameters manage the validity time of information 521 advertised in TC messages: 523 T_HOLD_TIME - is used to define the minimum value in the 524 VALIDITY_TIME TLV included in all TC messages sent by this node. 525 If a single value of parameter TC_HOP_LIMIT (see Section 5.6) is 526 used then this will be the only value in that TLV. 528 A_HOLD_TIME - is the period during which TC messages are sent after 529 they no longer have any advertised information to report, but are 530 sent in order to accelerate outdated information removal by other 531 nodes. 533 The following constraints apply to these parameters: 535 o T_HOLD_TIME > 0 537 o A_HOLD_TIME >= 0 539 o T_HOLD_TIME >= TC_INTERVAL 541 o If TC messages can be lost, then both T_HOLD_TIME and A_HOLD_TIME 542 SHOULD be significantly greater than TC_INTERVAL; a value >= 3 x 543 TC_INTERVAL is RECOMMENDED. 545 o T_HOLD_TIME MUST be representable as described in [timetlv]. 547 5.4. Received Message Validity Times 549 The following parameters manage the validity time of recorded 550 received message information: 552 RX_HOLD_TIME - is an interface parameter, and is the period after 553 receipt of a message by the appropriate OLSRv2 interface of this 554 node for which that information is recorded, in order that the 555 message is recognized as having been previously received on this 556 OLSRv2 interface. 558 P_HOLD_TIME - is the period after receipt of a message which is 559 processed by this node for which that information is recorded, in 560 order that the message is not processed again if received again. 562 F_HOLD_TIME - is the period after receipt of a message which is 563 forwarded by this node for which that information is recorded, in 564 order that the message is not forwarded again if received again. 566 The following constraints apply to these parameters: 568 o RX_HOLD_TIME > 0 570 o P_HOLD_TIME > 0 572 o F_HOLD_TIME > 0 574 o All of these parameters SHOULD be greater than the maximum 575 difference in time that a message may take to traverse the MANET, 576 taking into account any message forwarding jitter as well as 577 propagation, queuing, and processing delays. 579 5.5. Jitter 581 If jitter, as defined in [RFC5148], is used then these parameters are 582 as follows: 584 TP_MAXJITTER - represents the value of MAXJITTER used in [RFC5148] 585 for periodically generated TC messages sent by this node. 587 TT_MAXJITTER - represents the value of MAXJITTER used in [RFC5148] 588 for externally triggered TC messages sent by this node. 590 F_MAXJITTER - represents the default value of MAXJITTER used in 591 [RFC5148] for messages forwarded by this node. However before 592 using F_MAXJITTER a node MAY attempt to deduce a more appropriate 593 value of MAXJITTER, for example based on any INTERVAL_TIME or 594 VALIDITY_TIME TLVs contained in the message to be forwarded. 596 For constraints on these parameters see [RFC5148]. 598 5.6. Hop Limit Parameter 600 The parameter TC_HOP_LIMIT is the hop limit set in each TC message. 601 TC_HOP_LIMIT MAY be a single fixed value, or MAY be different in TC 602 messages sent by the same node. However each other node, at any hop 603 count distance, SHOULD see a regular pattern of TC messages, in order 604 that meaningful values of INTERVAL_TIME and VALIDITY_TIME TLVs at 605 each hop count distance can be included as defined in [timetlv]. 606 Thus the pattern of TC_HOP_LIMIT SHOULD be defined to have this 607 property. For example the repeating pattern (255 4 4) satisfies this 608 property (having period TC_INTERVAL at hop counts up to 4, inclusive, 609 and 3 x TC_INTERVAL at hop counts greater than 4), but the repeating 610 pattern (255 255 4 4) does not satisfy this property because at hop 611 counts greater than 4, message intervals are alternately TC_INTERVAL 612 and 3 x TC_INTERVAL. 614 The following constraints apply to this parameter: 616 o The maximum value of TC_HOP_LIMIT >= the network diameter in hops, 617 a value of 255 is RECOMMENDED. 619 o All values of TC_HOP_LIMIT >= 2. 621 5.7. Willingness 623 Each node has a WILLINGNESS parameter, which MUST be in the range 624 WILL_NEVER to WILL_ALWAYS, inclusive, and represents its willingness 625 to be an MPR, and hence its willingness to forward messages and be an 626 intermediate node on routes. If a node has WILLINGNESS == WILL_NEVER 627 it does not perform these tasks. A MANET using OLSRv2 with too many 628 nodes with WILLINGNESS == WILL_NEVER will not function; it MUST be 629 ensured, by administrative or other means, that this does not happen. 631 Nodes MAY have different WILLINGNESS values; however the three 632 constants WILL_NEVER, WILL_DEFAULT and WILL_ALWAYS MUST have the 633 values defined in Section 5.7. (Use of WILLINGNESS == WILL_DEFAULT 634 allows a node to avoid including an MPR_WILLING TLV in its TC 635 messages, use of WILLINGNESS == WILL_ALWAYS means that a node will 636 always be selected as an MPR by all symmetric 1-hop neighbors.) 638 The following constraints apply to this parameter: 640 o WILLINGNESS >= WILL_NEVER 642 o WILLINGNESS <= WILL_ALWAYS 644 5.8. Parameter Change Constraints 646 This section presents guidelines, applicable if protocol parameters 647 are changed dynamically. 649 O_HOLD_TIME 651 * If O_HOLD_TIME for a node changes, then O_time for all 652 Originator Tuples MAY be changed. 654 TC_INTERVAL 656 * If the TC_INTERVAL for a node increases, then the next TC 657 message generated by this node MUST be generated according to 658 the previous, shorter, TC_INTERVAL. Additional subsequent TC 659 messages MAY be generated according to the previous, shorter, 660 TC_INTERVAL. 662 * If the TC_INTERVAL for a node decreases, then the following TC 663 messages from this node MUST be generated according to the 664 current, shorter, TC_INTERVAL. 666 RX_HOLD_TIME 668 * If RX_HOLD_TIME for an OLSRv2 interface changes, then RX_time 669 for all Received Tuples for that OLSRv2 interface MAY be 670 changed. 672 P_HOLD_TIME 674 * If P_HOLD_TIME changes, then P_time for all Processed Tuples 675 MAY be changed. 677 F_HOLD_TIME 679 * If F_HOLD_TIME changes, then F_time for all Forwarded Tuples 680 MAY be changed. 682 TP_MAXJITTER 684 * If TP_MAXJITTER changes, then the periodic TC message schedule 685 on this node MAY be changed immediately. 687 TT_MAXJITTER 689 * If TT_MAXJITTER changes, then externally triggered TC messages 690 on this node MAY be rescheduled. 692 F_MAXJITTER 694 * If F_MAXJITTER changes, then TC messages waiting to be 695 forwarded with a delay based on this parameter MAY be 696 rescheduled. 698 TC_HOP_LIMIT 700 * If TC_HOP_LIMIT changes, and the node uses multiple values 701 after the change, then message intervals and validity times 702 included in TC messages MUST be respected. The simplest way to 703 do this is to start any new repeating pattern of TC_HOP_LIMIT 704 values with its largest value. 706 6. Information Bases 708 Each node maintains the Information Bases described in the following 709 sections. These are used for describing the protocol in this 710 document. An implementation of this protocol MAY maintain this 711 information in the indicated form, or in any other organization which 712 offers access to this information. In particular note that it is not 713 necessary to remove Tuples from Sets at the exact time indicated, 714 only to behave as if the Tuples were removed at that time. 716 The purpose of OLSRv2 is to determine the Routing Set, which may be 717 used to update IP's Routing Table, providing "next hop" routing 718 information for IP datagrams. OLSRv2 maintains the following 719 Information Bases: 721 Local Information Base - as defined in [nhdp], extended by the 722 addition of an Originator Set, defined in Section 6.1.1 and a 723 Local Attached Network Set, defined in Section 6.1.2. 725 Interface Information Bases - as defined in [nhdp], one Interface 726 Information Base for each OLSRv2 interface. 728 Node Information Base - as defined in [nhdp], extended by the 729 addition of three elements to each Neighbor Tuple, as defined in 730 Section 6.2. 732 Topology Information Base - this Information Base is specific to 733 OLSRv2, and is defined in Section 6.3. 735 Processing and Forwarding Information Base - this Information Base 736 is specific to OLSRv2, and is defined in Section 6.4. 738 The ordering of sequence numbers, when considering which is the 739 greater, is as defined in Section 18. 741 6.1. Local Information Base 743 The Local Information Base as defined in [nhdp] is extended by the 744 addition of an Originator Set, defined in Section 6.1.1, and a Local 745 Attached Network Set, defined in Section 6.1.2. 747 6.1.1. Originator Set 749 A node's Originator Set records addresses that were recently 750 originator addresses. If a node's originator address is immutable 751 then this set is always empty and MAY be omitted. It consists of 752 Originator Tuples: 754 (O_orig_addr, O_time) 756 where: 758 O_orig_addr is a recently used originator address; 760 O_time specifies the time at which this Tuple expires and MUST be 761 removed. 763 6.1.2. Local Attached Network Set 765 A node's Local Attached Network Set records its local non-OLSRv2 766 interfaces that can act as gateways to other networks. The Local 767 Attached Network Set is not modified by this protocol. This protocol 768 MAY respond to changes to the Local Attached Network Set, which MUST 769 reflect corresponding changes in the node's status. It consists of 770 Local Attached Network Tuples: 772 (AL_net_addr, AL_dist) 774 where: 776 AL_net_addr is the network address of an attached network which can 777 be reached via this node. 779 AL_dist is the number of hops to the network with address 780 AL_net_addr from this node. 782 Attached networks local to this node SHOULD be treated as local non- 783 MANET interfaces, and added to the Local Interface Set, as specified 784 in [nhdp], rather than being added to the Local Attached Network Set. 786 An attached network MAY also be attached to other nodes. 788 It is not the responsibility of OLSRv2 to maintain routes from this 789 node to networks recorded in the Local Attached Network Set. 791 6.2. Node Information Base 793 Each Neighbor Tuple in the Neighbor Set, defined in [nhdp], has these 794 additional elements: 796 N_willingness is the node's willingness to be selected as an MPR, in 797 the range from WILL_NEVER to WILL_ALWAYS, both inclusive; 799 N_mpr is a boolean flag, describing if this neighbor is selected as 800 an MPR by this node; 802 N_mpr_selector is a boolean flag, describing if this neighbor has 803 selected this node as an MPR, i.e. is an MPR selector of this 804 node. 806 6.3. Topology Information Base 808 The Topology Information Base stores information required for the 809 generation and processing of TC messages, and information received in 810 TC messages. The Advertised Neighbor Set contains interface 811 addresses of symmetric 1-hop neighbors which are to be reported in TC 812 messages. The Advertising Remote Node Set, the Topology Set and the 813 Attached Network Set record information received in TC messages. 815 Additionally, a Routing Set is maintained, derived from the 816 information recorded in the Neighborhood Information Base, Topology 817 Set, Attached Network Set and Advertising Remote Node Set. 819 6.3.1. Advertised Neighbor Set 821 A node's Advertised Neighbor Set contains interface addresses of 822 symmetric 1-hop neighbors which are to be advertised through TC 823 messages: 825 {A_neighbor_iface_addr} 827 In addition, an Advertised Neighbor Set Sequence Number (ANSN) is 828 maintained. Each time the Advertised Neighbor Set is updated, the 829 ANSN MUST be incremented. The ANSN MUST also be incremented if there 830 is a change to the set of Local Attached Network Tuples that are to 831 be advertised in the node's TC messages. 833 6.3.2. Advertising Remote Node Set 835 A node's Advertising Remote Node Set records information describing 836 each remote node in the network that transmits TC messages. It 837 consists of Advertising Remote Node Tuples: 839 (AR_orig_addr, AR_seq_number, AR_iface_addr_list, AR_time) 841 where: 843 AR_orig_addr is the originator address of a received TC message, 844 note that this does not include a prefix length; 846 AR_seq_number is the greatest ANSN in any TC message received which 847 originated from the node with originator address AR_orig_addr 848 (i.e. which contributed to the information contained in this 849 Tuple); 851 AR_iface_addr_list is an unordered list of the interface addresses 852 of the node with originator address AR_orig_addr; 854 AR_time is the time at which this Tuple expires and MUST be removed. 856 6.3.3. Topology Set 858 A node's Topology Set records topology information about the network. 859 It consists of Topology Tuples: 861 (T_dest_iface_addr, T_orig_addr, T_seq_number, T_time) 863 where: 865 T_dest_iface_addr is an interface address of a destination node, 866 which may be reached in one hop from the node with originator 867 address T_orig_addr; 869 T_orig_addr is the originator address of a node which is the last 870 hop on a path towards the node with interface address 871 T_dest_iface_addr, note that this does not include a prefix 872 length; 874 T_seq_number is the greatest ANSN in any TC message received which 875 originated from the node with originator address T_orig_addr (i.e. 876 which contributed to the information contained in this Tuple); 878 T_time specifies the time at which this Tuple expires and MUST be 879 removed. 881 6.3.4. Attached Network Set 883 A node's Attached Network Set records information about networks 884 attached to other nodes. It consists of Attached Network Tuples: 886 (AN_net_addr, AN_orig_addr, AN_dist, AN_seq_number, AN_time) 888 where: 890 AN_net_addr is the network address of an attached network, which may 891 be reached via the node with originator address AN_orig_addr; 893 AN_orig_addr is the originator address of a node which can act as 894 gateway to the network with address AN_net_addr, note that this 895 does not include a prefix length; 897 AN_dist is the number of hops to the network with address 898 AN_net_addr from the node with originator address AN_orig_addr; 900 AN_seq_number is the greatest ANSN in any TC message received which 901 originated from the node with originator address AN_orig_addr 902 (i.e. which contributed to the information contained in this 903 Tuple); 905 AN_time specifies the time at which this Tuple expires and MUST be 906 removed. 908 6.3.5. Routing Set 910 A node's Routing Set records the selected path to each destination 911 for which a route is known. It consists of Routing Tuples: 913 (R_dest_addr, R_next_iface_addr, R_dist, R_local_iface_addr) 915 where: 917 R_dest_addr is the address of the destination, either the address of 918 an interface of a destination node, or the network address of an 919 attached network; 921 R_next_iface_addr is the OLSRv2 interface address of the "next hop" 922 on the selected path to the destination; 924 R_dist is the number of hops on the selected path to the 925 destination; 927 R_local_iface_addr is the address of the local OLSRv2 interface over 928 which a packet MUST be sent to reach the destination by the 929 selected path. 931 6.4. Processing and Forwarding Information Base 933 The Processing and Forwarding Information Base records information 934 required to ensure that a message is processed at most once and is 935 forwarded at most once per OLSRv2 interface of a node, using MPR 936 flooding. 938 6.4.1. Received Set 940 A node has a Received Set per local OLSRv2 interface. Each Received 941 Set records the signatures of messages which have been received over 942 that OLSRv2 interface. Each consists of Received Tuples: 944 (RX_type, RX_orig_addr, RX_seq_number, RX_time) 946 where: 948 RX_type is the received message type, or zero if the received 949 message sequence number is not type-specific; 951 RX_orig_addr is the originator address of the received message; 953 RX_seq_number is the message sequence number of the received 954 message; 956 RX_time specifies the time at which this Tuple expires and MUST be 957 removed. 959 6.4.2. Processed Set 961 A node's Processed Set records signatures of messages which have been 962 processed by the node. It consists of Processed Tuples: 964 (P_type, P_orig_addr, P_seq_number, P_time) 966 where: 968 P_type is the processed message type, or zero if the processed 969 message sequence number is not type-specific; 971 P_orig_addr is the originator address of the processed message; 973 P_seq_number is the message sequence number of the processed 974 message; 976 P_time specifies the time at which this Tuple expires and MUST be 977 removed. 979 6.4.3. Forwarded Set 981 A node's Forwarded Set records signatures of messages which have been 982 processed by the node. It consists of Forwarded Tuples: 984 (F_type, F_orig_addr, F_seq_number, F_time) 986 where: 988 F_type is the forwarded message type, or zero if the forwarded 989 message sequence number is not type-specific; 991 F_orig_addr is the originator address of the forwarded message; 993 F_seq_number is the message sequence number of the forwarded 994 message; 996 F_time specifies the time at which this Tuple expires and MUST be 997 removed. 999 6.4.4. Relay Set 1001 A node has a Relay Set per local OLSRv2 interface. Each Relay Set 1002 records the OLSRv2 interface addresses of symmetric 1-hop neighbors, 1003 such that the node is to forward messages received from those 1004 neighbors' OLSRv2 interfaces, on that local OLSRv2 interface, if not 1005 otherwise excluded from forwarding that message (e.g. by it having 1006 been previously forwarded): 1008 {RY_neighbor_iface_addr} 1010 7. Packet Processing and Message Forwarding 1012 On receiving a packet, as defined in [packetbb], a node examines the 1013 packet header and each of the message headers. If the message type 1014 is known to the node, the message is processed locally according to 1015 the specification for that message type. The message is also 1016 independently evaluated for forwarding. 1018 7.1. Actions when Receiving an OLSRv2 Packet 1020 On receiving a packet, a node MUST perform the following tasks: 1022 1. The packet MAY be fully parsed on reception, or the packet and 1023 its messages MAY be parsed only as required. (It is possible to 1024 parse the packet header, or determine its absence, without 1025 parsing any messages. It is possible to divide the packet into 1026 messages without fully parsing the message headers. It is 1027 possible to determine whether a message is to be forwarded, and 1028 to forward it, without parsing its body. It is possible to 1029 determine whether a message is to be processed without parsing 1030 its body.) 1032 2. If parsing fails at any point the relevant entity (packet or 1033 message) MUST be silently discarded, other parts of the packet 1034 (up to the whole packet) MAY be silently discarded. 1036 3. Otherwise: 1038 1. If the packet header is present and it contains a packet TLV 1039 block, then each TLV in it is processed according to its type 1040 if recognized, otherwise the TLV is ignored. 1042 2. Otherwise each message in the packet, if any, is treated 1043 according to Section 7.2. 1045 7.2. Actions when Receiving an OLSRv2 Message 1047 A node MUST perform the following tasks for each received message: 1049 1. If the message header cannot be correctly parsed according to the 1050 specification in [packetbb], or if the node recognizes from the 1051 originator address of the message that the message is one which 1052 the receiving node itself originated (i.e. is the current 1053 originator address of the node, or is an O_orig_addr in an 1054 Originator Tuple) then the message MUST be silently discarded. 1056 2. Otherwise: 1058 1. If the message is a HELLO message, then the message is 1059 processed according to Section 10. 1061 2. Otherwise: 1063 1. Define the "dependent message type" of the message to 1064 equal the message type if the mistypedep bit of the 1065 message semantics octet in the message header is set 1066 ('1'), or to equal 0 otherwise. 1068 2. If the message is of a known type, including being a TC 1069 message, then the message is considered for processing 1070 according to Section 7.3, AND; 1072 3. If for the message: 1074 - is present and > 1, AND; 1076 - is not present or < 255 1078 then the message is considered for forwarding according 1079 to Section 7.4. 1081 7.3. Message Considered for Processing 1083 If a message (the "current message") is considered for processing, 1084 then the following tasks MUST be performed: 1086 1. If a Processed Tuple exists with: 1088 * P_type == the dependent message type of the current message, 1089 AND; 1091 * P_orig_addr == the originator address of the current message, 1092 AND; 1094 * P_seq_number == the message sequence number of the current 1095 message; 1097 then the current message MUST NOT be processed. 1099 2. Otherwise: 1101 1. Create a Processed Tuple with: 1103 + P_type = the dependent message type of the current 1104 message; 1106 + P_orig_addr = the originator address of the current 1107 message; 1109 + P_seq_number = the sequence number of the current message; 1111 + P_time = current time + P_HOLD_TIME. 1113 2. Process the current message according to its type. 1115 7.4. Message Considered for Forwarding 1117 If a message is considered for forwarding, and it is either of a 1118 message type defined in this document (i.e. is a TC message) or of an 1119 unknown message type, then it MUST use the following algorithm. A 1120 message of a message type not defined in this document MAY, in an 1121 extension to this protocol, specify the use of this, or another 1122 algorithm. (Such an other algorithm MAY use the Received Set for the 1123 receiving interface, it SHOULD use the Forwarded Set similarly to the 1124 following algorithm.) 1126 If a message (the "current message") is considered for forwarding 1127 according to this algorithm, the following tasks MUST be performed: 1129 1. If the sending interface address (the source address of the IP 1130 datagram containing the current message) does not match (taking 1131 into account any address prefix) an OLSRv2 interface address in 1132 an L_neighbor_iface_addr_list of a Link Tuple, with L_status == 1133 SYMMETRIC, in the Link Set for the OLSRv2 interface on which the 1134 current message was received (the "receiving interface") then the 1135 current message MUST be silently discarded. 1137 2. Otherwise: 1139 1. If a Received Tuple exists in the Received Set for the 1140 receiving interface, with: 1142 + RX_type == the dependent message type of the current 1143 message, AND; 1145 + RX_orig_addr == the originator address of the current 1146 message, AND; 1148 + RX_seq_number == the sequence number of the current 1149 message; 1151 then the current message MUST be silently discarded. 1153 2. Otherwise: 1155 1. Create a Received Tuple in the Received Set for the 1156 receiving interface with: 1158 - RX_type = the dependent message type of the current 1159 message; 1161 - RX_orig_addr = originator address of the current 1162 message; 1164 - RX_seq_number = sequence number of the current 1165 message; 1167 - RX_time = current time + RX_HOLD_TIME. 1169 2. If a Forwarded Tuple exists with: 1171 - F_type == the dependent message type of the current 1172 message, AND; 1174 - F_orig_addr == the originator address of the current 1175 message, AND; 1177 - F_seq_number == the sequence number of the current 1178 message. 1180 then the current message MUST be silently discarded. 1182 3. Otherwise if the sending interface address matches 1183 (taking account of any address prefix) an 1184 RY_neighbor_iface_addr in the Relay Set for the receiving 1185 interface, then: 1187 1. Create a Forwarded Tuple with: 1189 o F_type = the dependent message type of the current 1190 message; 1192 o F_orig_addr = originator address of the current 1193 message; 1195 o F_seq_number = sequence number of the current 1196 message; 1198 o F_time = current time + F_HOLD_TIME. 1200 2. The message header of the current message is modified 1201 by: 1203 o decrement in the message header by 1; 1205 o increment in the message header by 1. 1207 3. For each OLSRv2 interface of the node, include the 1208 message in a packet to be transmitted on that OLSRv2 1209 interface, as described in Section 8. This packet 1210 may contain other forwarded messages and/or messages 1211 generated by this node. Forwarded messages may be 1212 jittered as described in [RFC5148]. The value of 1213 MAXJITTER used in jittering a forwarded message MAY 1214 be based on information in that message (in 1215 particular any INTERVAL_TIME or VALIDITY_TIME TLVs in 1216 that message) or otherwise SHOULD be with a maximum 1217 delay of F_MAXJITTER. A node MAY modify the jitter 1218 applied to a message in order to more efficiently 1219 combine messages in packets, as long as the maximum 1220 jitter is not exceeded. 1222 8. Packets and Messages 1224 Nodes using OLSRv2 exchange information through messages. One or 1225 more messages sent by a node at the same time SHOULD be combined into 1226 a single packet. These messages may have originated at the sending 1227 node, or have originated at another node and are forwarded by the 1228 sending node. Messages with different originating nodes MAY be 1229 combined in the same packet. Messages from other protocols defined 1230 using [packetbb] MAY be combined in the same packet. 1232 The packet and message format used by OLSRv2 is defined in 1233 [packetbb], where: 1235 o OLSRv2 packets MAY include packet TLVs, however OLSRv2 itself does 1236 not specify any packet TLVs. 1238 o All references in this specification to TLVs that do not indicate 1239 a type extension, assume Type Extension == 0. TLVs in processed 1240 messages with a type extension which is neither zero as so 1241 assumed, nor a specifically indicated non-zero type extension, are 1242 ignored. 1244 Other options defined in [packetbb] may be freely used, in particular 1245 any other values of , , or consistent with their specifications. 1248 The remainder of this section defines, within the framework of 1249 [packetbb], message types and TLVs specific to OLSRv2. 1251 8.1. HELLO Messages 1253 A HELLO message in OLSRv2 is generated as specified in [nhdp]. 1254 Additionally, an OLSRv2 node: 1256 o MUST include TLV(s) with Type == MPR associated with all OLSRv2 1257 interface addresses that: 1259 * are included in the HELLO message associated with a TLV with 1260 Type == LINK_STATUS and Value == SYMMETRIC; AND 1262 * are included in a Neighbor Tuple with N_mpr == true. 1264 If there is more than one copy of such an address in the HELLO 1265 message, then this applies to the specific copy of the address 1266 with which the LINK_STATUS TLV is associated. 1268 o MUST NOT include any TLVs with Type == MPR associated with any 1269 other addresses. 1271 o MAY include a message TLV with Type == MPR_WILLING, indicating the 1272 node's willingness to be selected as an MPR. 1274 8.1.1. HELLO Message TLVs 1276 In a HELLO message, a node MUST include an MPR_WILLING message TLV as 1277 specified in Table 1, unless WILLINGNESS == WILL_DEFAULT (in which 1278 case it MAY be included). A node MUST NOT include more than one 1279 MPR_WILLING message TLV. 1281 +-------------+--------+--------------------------------------------+ 1282 | Type | Value | Value | 1283 | | Length | | 1284 +-------------+--------+--------------------------------------------+ 1285 | MPR_WILLING | 8 bits | Node parameter WILLINGNESS; unused bits | 1286 | | | (based on the maximum willingness value | 1287 | | | WILL_ALWAYS) are RESERVED and SHOULD be | 1288 | | | set to zero. | 1289 +-------------+--------+--------------------------------------------+ 1291 Table 1 1293 If a node does not advertise an MPR_WILLING TLV in a HELLO message, 1294 then the node MUST be assumed to have WILLINGNESS equal to 1295 WILL_DEFAULT. 1297 8.1.2. HELLO Message Address Block TLVs 1299 In a HELLO message, a node MAY include MPR address block TLV(s) as 1300 specified in Table 2. 1302 +------+--------------+-------+ 1303 | Type | Value Length | Value | 1304 +------+--------------+-------+ 1305 | MPR | 0 bits | None. | 1306 +------+--------------+-------+ 1308 Table 2 1310 8.2. TC Messages 1312 A TC message MUST contain: 1314 o , and elements in its 1315 message header, as specified in [packetbb]. 1317 o A element in its message header if the message 1318 contains either a VALIDITY_TIME or an INTERVAL_TIME TLV indicating 1319 more than one time value according to distance. 1321 o A single message TLV with Type == CONT_SEQ_NUM, and Type Extension 1322 == COMPLETE or Type Extension == INCOMPLETE, as specified in 1323 Section 8.2.1 (for complete and incomplete TC messages, 1324 respectively). 1326 o A message TLV with Type == VALIDITY_TIME, as specified in 1327 [timetlv]. The options included in [timetlv] for representing 1328 zero and infinite times MUST NOT be used. 1330 o All of the node's interface addresses. These MUST be included in 1331 the message's address blocks, unless: 1333 * the node has a single interface, with a single interface 1334 address with maximum prefix length, and 1336 * that address is the node's originator address. 1338 In this exceptional case, the address will be included as the 1339 message's originator address, and MAY be omitted from the 1340 message's address blocks. 1342 o TLV(s) with Type == LOCAL_IF and Value == UNSPEC_IF associated 1343 with all of the node's interface addresses. 1345 o If the TC message is complete, all addresses in the Advertised 1346 Address Set and all addresses in the Local Attached Network Set, 1347 the latter (only) with associated GATEWAY address block TLV(s), as 1348 specified in Section 8.2.2. 1350 A TC message SHOULD have the mistypedep bit of , as 1351 defined in [packetbb], cleared ('0'). 1353 A TC message MAY contain: 1355 o If the TC message is incomplete, any addresses in the Advertised 1356 Address Set and any addresses in the Local Attached Network Set, 1357 the latter (only) with associated GATEWAY address block TLV(s), as 1358 specified in Section 8.2.2. 1360 o A message TLV with Type == INTERVAL_TIME, as specified in 1361 [timetlv]. The options included in [timetlv] for representing 1362 zero and infinite times MUST NOT be used. 1364 8.2.1. TC Message TLVs 1366 In a TC message, a node MUST include a single CONT_SEQ_NUM message 1367 TLV, as specified in Table 3, and with Type Extension == COMPLETE or 1368 Type Extension == INCOMPLETE, according to whether the TC message is 1369 complete or incomplete. 1371 +--------------+------------+---------------------------------------+ 1372 | Type | Value | Value | 1373 | | Length | | 1374 +--------------+------------+---------------------------------------+ 1375 | CONT_SEQ_NUM | 8 bits | The ANSN contained in the Advertised | 1376 | | | Neighbor Set. | 1377 +--------------+------------+---------------------------------------+ 1379 Table 3 1381 8.2.2. TC Message Address Block TLVs 1383 In a TC message, a node MAY include GATEWAY address block TLV(s) as 1384 specified in Table 4. 1386 +---------+--------------+-------------------------------------+ 1387 | Type | Value Length | Value | 1388 +---------+--------------+-------------------------------------+ 1389 | GATEWAY | 8 bits | Number of hops to attached network. | 1390 +---------+--------------+-------------------------------------+ 1392 Table 4 1394 GATEWAY address block TLV(s) MUST be associated with all attached 1395 network addresses, and MUST NOT be associated with any other 1396 addresses. 1398 9. HELLO Message Generation 1400 An OLSRv2 HELLO message is composed and generated as defined in 1401 [nhdp], with the following additions: 1403 o A message TLV with Type == MPR_WILLING and Value == the node 1404 parameter WILLINGNESS MUST be included, unless WILLINGNESS == 1405 WILL_DEFAULT (in which case it MAY be included). 1407 o For each address which is included in the message with an 1408 associated TLV with Type == LINK_STATUS and Value == SYMMETRIC, 1409 and is of an MPR (i.e. the address is in the 1410 N_neighbor_iface_addr_list of a Neighbor Tuple with N_mpr == 1411 true), an address block TLV with Type == MPR MUST be included. 1412 This TLV MUST be associated with the same copy of the address as 1413 is the TLV with Type == LINK_STATUS. 1415 o For each address which is included in the message and is not 1416 associated with a TLV with Type == LINK_STATUS and Value == 1417 SYMMETRIC, or is not of an MPR (i.e. the address is not in the 1418 N_neighbor_iface_addr_list of a Neighbor Tuple with N_mpr == 1419 true), an address block TLV with Type == MPR MUST NOT be 1420 associated with any copy of this address. 1422 o An additional HELLO message MAY be sent when the node's set of 1423 MPRs changes, in addition to the cases specified in [nhdp], and 1424 subject to the same constraints. 1426 9.1. HELLO Message: Transmission 1428 HELLO messages are included in packets as specified in [packetbb]. 1429 These packets may contain other messages, including TC messages. 1431 10. HELLO Message Processing 1433 Subsequent to the processing of HELLO messages, as specified in 1434 [nhdp], the node MUST identify the Neighbor Tuple which was created 1435 or updated by the processing specified in [nhdp] (the "current 1436 Neighbor Tuple") and update N_willingness as described in 1437 Section 10.1 and N_mpr_selector as described in Section 10.2. 1438 Following these, the node MUST also perform the processing defined in 1439 Section 10.3. 1441 10.1. Updating Willingness 1443 N_willingness in the current Neighbor Tuple is updated as follows: 1445 1. If the HELLO message contains a message TLV with Type == 1446 MPR_WILLING then N_willingness is set to the value of that TLV; 1448 2. Otherwise, N_willingness is set to WILL_DEFAULT. 1450 10.2. Updating MPR Selectors 1452 N_mpr_selector is updated as follows: 1454 1. If a node finds any of its local OLSRv2 interface addresses with 1455 an associated TLV with Type == MPR in the HELLO message 1456 (indicating that the originator node has selected the receiving 1457 node as an MPR), then N_mpr_selector in the current Neighbor 1458 Tuple is set true. 1460 2. Otherwise, if a node finds any of its own interface addresses 1461 with an associated TLV with Type == LINK_STATUS and Value == 1462 SYMMETRIC in the HELLO message, then N_mpr_selector in the 1463 current Neighbor Tuple is set false. 1465 10.3. Symmetric 1-Hop and 2-Hop Neighborhood Changes 1467 A node MUST also perform the following: 1469 1. If N_symmetric of a Neighbor Tuple changes from true to false, 1470 then N_mpr_selector of that Neighbor Tuple MUST be set false. 1472 2. The set of MPRs of a node MUST be recalculated if: 1474 * a Link Tuple is added with L_status == SYMMETRIC, OR; 1476 * a Link Tuple with L_status == SYMMETRIC is removed, OR; 1477 * a Link Tuple with L_status == SYMMETRIC changes to having 1478 L_status == HEARD or L_status == LOST, OR; 1480 * a Link Tuple with L_status == HEARD or L_status == LOST 1481 changes to having L_status == SYMMETRIC, OR; 1483 * a 2-Hop Tuple is added or removed, OR; 1485 * the N_willingness of a Neighbor Tuple with N_symmetric == true 1486 changes from WILL_NEVER to any other value, OR; 1488 * the N_willingness of a Neighbor Tuple with N_symmetric == true 1489 and N_mpr == true changes to WILL_NEVER from any other value, 1490 OR; 1492 * the N_willingness of a Neighbor Tuple with N_symmetric == true 1493 and N_mpr == false changes to WILL_ALWAYS from any other 1494 value. 1496 3. Otherwise the set of MPRs of a node MAY be recalculated if the 1497 N_willingness of a Neighbor Tuple with N_symmetric == true 1498 changes in any other way; it SHOULD be recalculated if N_mpr == 1499 false and this is an increase in N_willingness or if N_mpr == 1500 true and this is a decrease in N_willingness. 1502 If the set of MPRs of a node is recalculated, this MUST be as 1503 described in Section 14. Before that calculation, the N_mpr of all 1504 Neighbor Tuples are set false. After that calculation the N_mpr of 1505 all Neighbor Tuples representing symmetric 1-hop neighbors which are 1506 chosen as MPRs, are set true. 1508 11. TC Message Generation 1510 A node with one or more OLSRv2 interfaces, and with a non-empty 1511 Advertised Neighbor Set or a non-empty Local Attached Network Set 1512 MUST generate TC messages. A node with an empty Advertised Neighbor 1513 Set and empty Local Attached Network Set SHOULD also generate "empty" 1514 TC messages for a period A_HOLD_TIME after it last generated a non- 1515 empty TC message. TC messages (non-empty and empty) are generated 1516 according to the following: 1518 1. The message hop count, if included, MUST be set to zero. 1520 2. The message hop limit MUST be set to a value greater than 1. A 1521 node MAY use the same hop limit TC_HOP_LIMIT in all TC messages, 1522 or use different values of the hop limit TC_HOP_LIMIT in TC 1523 messages, see Section 5.6. 1525 3. The message MUST contain a message TLV with Type == CONT_SEQ_NUM 1526 and Value == ANSN from the Advertised Neighbor Set. If the TC 1527 message is complete then this message TLV MUST have Type 1528 Extension == COMPLETE, otherwise it MUST have Type Extension == 1529 INCOMPLETE. 1531 4. The message MUST contain a message TLV with Type == 1532 VALIDITY_TIME, as specified in [timetlv]. If all TC messages are 1533 sent with the same hop limit then this TLV MUST have Value == 1534 T_HOLD_TIME. If TC messages are sent with different hop limits 1535 (more than one value of TC_HOP_LIMIT) then this TLV MUST specify 1536 times which vary with the number of hops distance appropriate to 1537 the chosen pattern of TC message hop limits, as specified in 1538 [timetlv], these times SHOULD be appropriate multiples of 1539 T_HOLD_TIME. 1541 5. The message MAY contain a message TLV with Type == INTERVAL_TIME, 1542 as specified in [timetlv]. If all TC messages are sent with the 1543 same hop limit then this TLV MUST have Value == TC_INTERVAL. If 1544 TC messages are sent with different hop limits, then this TLV 1545 MUST specify times which vary with the number of hops distance 1546 appropriate to the chosen pattern of TC message hop limits, as 1547 specified in [timetlv], these times SHOULD be appropriate 1548 multiples of TC_INTERVAL. 1550 6. Unless the node has a single interface, with a single interface 1551 address with maximum prefix length, and that address is the 1552 node's originator address, the message MUST contain all of the 1553 node's interface addresses (i.e. all addresses in an 1554 I_local_iface_addr_list) in its address blocks. 1556 7. All addresses of the node's interfaces that are included in an 1557 address block MUST be associated with a TLV with Type == LOCAL_IF 1558 and Value == UNSPEC_IF. 1560 8. A complete message MUST include, and an incomplete message MAY 1561 include, in its address blocks: 1563 1. Each A_neighbor_iface_addr from the Advertised Neighbor Set; 1565 2. AL_net_addr from each Local Attached Neighbor Tuple, each 1566 associated with a TLV with Type == GATEWAY and Value == 1567 AL_dist. 1569 11.1. TC Message: Transmission 1571 Complete TC messages are generated and transmitted periodically on 1572 all OLSRv2 interfaces, with a default interval between two 1573 consecutive TC transmissions by the same node of TC_INTERVAL. 1575 TC messages MAY be generated in response to a change of contents, 1576 indicated by a change in ANSN. In this case a node MAY send a 1577 complete TC message, and if so MAY re-start its TC message schedule. 1578 Alternatively a node MAY send an incomplete TC message with at least 1579 the new content in its address blocks. Note that a node cannot 1580 report removal of advertised content using an incomplete TC message. 1582 When sending a TC message in response to a change of contents, a node 1583 must respect a minimum interval of TC_MIN_INTERVAL between generated 1584 TC messages. Sending an incomplete TC message MUST NOT cause the 1585 interval between complete TC messages to be increased, and thus a 1586 node MUST NOT send an incomplete TC message if within TC_MIN_INTERVAL 1587 of the next scheduled complete TC message. 1589 The generation of TC messages, whether scheduled or triggered by a 1590 change of contents MAY be jittered as described in [RFC5148]. The 1591 values of MAXJITTER used SHOULD be: 1593 o TP_MAXJITTER for periodic TC message generation; 1595 o TT_MAXJITTER for responsive TC message generation. 1597 TC messages are included in packets as specified in [packetbb]. 1598 These packets MAY contain other messages, including HELLO messages 1599 and TC messages with different originator addresses. TC messages are 1600 forwarded according to the specification in Section 7.4. 1602 12. TC Message Processing 1604 When, according to Section 7.3, a TC message is to be "processed 1605 according to its type", this means that: 1607 o If any address associated with a TLV with Type == LOCAL_IF is one 1608 of the receiving node's current or recently used interface 1609 addresses (i.e. is in any I_local_iface_addr_list in the Local 1610 Interface Set or is equal to any IR_local_iface_addr in the 1611 Removed Interface Address Set), then the TC message MUST be 1612 discarded. 1614 o If the TC message does not contain exactly one message TLV with 1615 Type == CONT_SEQ_NUM and Type Extension == COMPLETE or Type 1616 Extension == INCOMPLETE, then the TC message MUST be discarded. 1618 o If the TC message contains a message TLV with Type == CONT_SEQ_NUM 1619 and Type Extension == COMPLETE, then processing according to 1620 Section 12.1 and then according to Section 12.2 is carried out. 1622 o If the TC message contains a message TLV with Type == CONT_SEQ_NUM 1623 and Type Extension == INCOMPLETE, then only processing according 1624 to Section 12.1 is carried out. 1626 12.1. Initial TC Message Processing 1628 For the purposes of this section: 1630 o "originator address" refers to the originator address in the TC 1631 message header. 1633 o "validity time" is calculated from the VALIDITY_TIME message TLV 1634 in the TC message according to the specification in [timetlv]. 1635 All information in the TC message has the same validity time. 1637 o "ANSN" is defined as being the value of the message TLV with Type 1638 == CONT_SEQ_NUM. 1640 o "sending address list" refers to the list of addresses in all 1641 address blocks which have associated TLV(s) with Type == LOCAL_IF 1642 and Value == UNSPEC_IF. If the sending address list is otherwise 1643 empty, then the message's originator address is added to the 1644 sending address list, with maximum prefix length. 1646 o Comparisons of sequence numbers are carried out as specified in 1647 Section 18. 1649 The TC message is processed as follows: 1651 1. The Advertising Remote Node Set is updated according to 1652 Section 12.1.1; if the TC message is indicated as discarded in 1653 that processing then the following steps are not carried out. 1655 2. The Topology Set is updated according to Section 12.1.2. 1657 3. The Attached Network Set is updated according to Section 12.1.3. 1659 12.1.1. Populating the Advertising Remote Node Set 1661 The node MUST update its Advertising Remote Node Set as follows: 1663 1. If there is an Advertising Remote Node Tuple with: 1665 * AR_orig_addr == originator address; AND 1667 * AR_seq_number > ANSN 1669 then the TC message MUST be discarded. 1671 2. Otherwise: 1673 1. If there is no Advertising Remote Node Tuple such that: 1675 + AR_orig_addr == originator address; 1677 then create an Advertising Remote Node Tuple with: 1679 + AR_orig_addr = originator address. 1681 2. This Advertising Remote Node Tuple (existing or new, the 1682 "current tuple") is then modified as follows: 1684 + AR_seq_number = ANSN; 1686 + AR_time = current time + validity time. 1688 + AR_iface_addr_list = sending address list 1690 3. For each other Advertising Remote Node Tuple (with a 1691 different AR_orig_addr, the "other tuple") whose 1692 AR_iface_addr_list contains any address in the 1693 AR_iface_addr_list of the current tuple: 1695 1. remove all Topology Tuples with T_orig_addr == 1696 AR_orig_addr of the other tuple; 1698 2. remove all Attached Network Tuples with AN_orig_addr == 1699 AR_orig_addr of the other tuple; 1701 3. remove the other tuple. 1703 12.1.2. Populating the Topology Set 1705 The node MUST update its Topology Set as follows: 1707 1. For each address (henceforth advertised address) in an address 1708 block which does not have an associated TLV with Type == 1709 LOCAL_IF, or an associated TLV with Type == GATEWAY: 1711 1. If there is no Topology Tuple such that: 1713 + T_dest_iface_addr == advertised address; AND 1715 + T_orig_addr == originator address 1717 then create a new Topology Tuple with: 1719 + T_dest_iface_addr = advertised address; 1721 + T_orig_addr = originator address. 1723 2. This Topology Tuple (existing or new) is then modified as 1724 follows: 1726 + T_seq_number = ANSN; 1728 + T_time = current time + validity time. 1730 12.1.3. Populating the Attached Network Set 1732 The node MUST update its Attached Network Set as follows: 1734 1. For each address (henceforth network address) in an address block 1735 which does not have an associated TLV with Type == LOCAL_IF, and 1736 does have an associated TLV with Type == GATEWAY: 1738 1. If there is no Attached Network Tuple such that: 1740 + AN_net_addr == network address; AND 1742 + AN_orig_addr == originator address 1744 then create a new Attached Network Tuple with: 1746 + AN_net_addr = network address; 1748 + AN_orig_addr = originator address 1750 2. This Attached Network Tuple (existing or new) is then 1751 modified as follows: 1753 + AN_dist = the value of the associated GATEWAY TLV; 1755 + AN_seq_number = ANSN; 1757 + AN_time = current time + validity time. 1759 12.2. Completing TC Message Processing 1761 The TC message is processed as follows: 1763 1. The Topology Set is updated according to Section 12.2.1. 1765 2. The Attached Network Set is updated according to Section 12.2.2. 1767 12.2.1. Purging the Topology Set 1769 The Topology Set MUST be updated as follows: 1771 1. Any Topology Tuples with: 1773 * T_orig_addr == originator address; AND 1775 * T_seq_number < ANSN 1777 MUST be removed. 1779 12.2.2. Purging the Attached Network Set 1781 The Attached Network Set MUST be updated as follows: 1783 1. Any Attached Network Tuples with: 1785 * AN_orig_addr == originator address; AND 1787 * AN_seq_number < ANSN 1789 MUST be removed. 1791 13. Information Base Changes 1793 1. The Originator Set in the Local Information Base MUST be updated 1794 when the node changes originator address. If there is no 1795 Originator Tuple with: 1797 * O_orig_addr == old originator address 1799 then create an Originator Tuple with: 1801 * O_orig_addr = old originator address 1803 This Originator Tuple (existing or new) is then modified as 1804 follows: 1806 * O_time = current time + O_HOLD_TIME 1808 2. The Topology Information Base MUST be changed when an Advertising 1809 Remote Node Tuple expires (AR_time is reached). The following 1810 changes are required before the Advertising Remote Node Tuple is 1811 removed: 1813 1. All Topology Tuples with: 1815 + T_orig_addr == AR_orig_addr of the Advertising Remote Node 1816 Tuple 1818 are removed. 1820 2. All Attached Network Tuples with: 1822 + AN_orig_addr == AR_orig_addr of the Advertising Remote 1823 Node Tuple 1825 are removed. 1827 14. Selecting MPRs 1829 Each node MUST select, from among its willing symmetric 1-hop 1830 neighbors, a subset of nodes as MPRs. MPRs are used to flood control 1831 messages from a node into the network, while reducing the number of 1832 retransmissions that will occur in a region. Thus, the concept of 1833 MPR flooding is an optimization of a classical flooding mechanism. 1834 MPRs MAY also be used to reduce the shared topology information in 1835 the network. Consequently, while it is not essential that the set of 1836 MPRs is minimal, keeping the number of MPRs small ensures that the 1837 overhead of OLSRv2 is kept at a minimum. 1839 A node MUST select MPRs for each of its OLSRv2 interfaces, but then 1840 forms the union of those sets as its single set of MPRs. This union 1841 MUST include all symmetric 1-hop neighbors with willingness 1842 WILL_ALWAYS. Only this overall set of MPRs is relevant, the recorded 1843 and used MPR relationship is one of nodes, not interfaces. Nodes MAY 1844 select their MPRs by any process which satisfies the conditions which 1845 follow. Nodes can freely interoperate whether they use the same or 1846 different MPR selection algorithms. 1848 For each OLSRv2 interface a node MUST select a set of MPRs. This set 1849 MUST have the properties that: 1851 o All of the selected MPRs are willing symmetric 1-hop neighbors, 1852 AND; 1854 o If the selecting node sends a message on that OLSRv2 interface, 1855 and that message is successfully forwarded by all of the selected 1856 MPRs for that interface, then all symmetric strict 2-hop neighbors 1857 of the selecting node through that OLSRv2 interface will receive 1858 that message on a symmetric link. 1860 Note that it is always possible to select a valid set of MPRs. The 1861 set of all willing symmetric 1-hop neighbors of a node is a (maximal) 1862 valid set of MPRs for that node. However a node SHOULD NOT select a 1863 symmetric 1-hop neighbor with willingness not equal to WILL_ALWAYS as 1864 an MPR if there are no symmetric strict 2-hop neighbors with a 1865 symmetric link to that symmetric 1-hop neighbor. Thus a node with no 1866 symmetric 1-hop neighbors with willingness WILL_ALWAYS and with no 1867 symmetric strict 2-hop neighbors SHOULD NOT select any MPRs. 1869 A node MAY select its MPRs for each OLSRv2 interface independently, 1870 or it MAY coordinate its MPR selections across its OLSRv2 interfaces, 1871 as long as the required condition is satisfied for each OLSRv2 1872 interface. Each node MAY select its MPRs independently from the MPR 1873 selection by other nodes, or it MAY, for example, give preference to 1874 nodes that either are, or are not, already selected as MPRs by other 1875 nodes. 1877 When selecting MPRs for each OLSRv2 interface independently, this MAY 1878 be done using information from the Link Set and 2-Hop Set of that 1879 OLSRv2 interface, and the Neighbor Set of the node (specifically the 1880 N_willingness elements). 1882 The selection of MPRs (overall, not per OLSRv2 interface) is recorded 1883 in the Neighbor Set of the node (using the N_mpr elements). A 1884 selected MPR MUST be a willing symmetric 1-hop neighbor (i.e. the 1885 corresponding N_symmetric == true, and the corresponding 1886 N_willingness is not equal to WILL_NEVER). 1888 A node MUST recalculate its MPRs whenever the currently selected set 1889 of MPRs does not still satisfy the required conditions. It MAY 1890 recalculate its MPRs if the current set of MPRs is still valid, but 1891 could be more efficient. It is sufficient to recalculate a node's 1892 MPRs when there is a change to any of the node's Link Sets affecting 1893 the symmetry of any link (addition or removal of a Link Tuple with 1894 L_status == SYMMETRIC, or change of any L_status to or from 1895 SYMMETRIC), any change to any of the node's 2-Hop Sets, or a change 1896 of the N_willingness (to or from WILL_NEVER or to WILL_ALWAYS is 1897 sufficient) of any Neighbor Tuple with N_symmetric == true. 1899 An algorithm that creates a set of MPRs that satisfies the required 1900 conditions is given in Appendix B. 1902 15. Populating Derived Sets 1904 The Relay Sets and the Advertised Neighbor Set of a node are denoted 1905 derived sets, since updates to these sets are not directly a function 1906 of message exchanges, but rather are derived from updates to other 1907 sets, in particular to the MPR selector status of other nodes 1908 recorded in the Neighbor Set. 1910 15.1. Populating the Relay Set 1912 The Relay Set for an OLSRv2 interface contains the set of OLSRv2 1913 interface addresses of those symmetric 1-hop neighbors for which this 1914 OLSRv2 interface is to relay broadcast traffic. This set MUST 1915 contain only addresses of OLSRv2 interfaces with which this OLSRv2 1916 interface has a symmetric link. This set MUST include all such 1917 addresses of all such OLSRv2 interfaces of nodes which are MPR 1918 selectors of this node. 1920 The Relay Set for an OLSRv2 interface of this node is thus created 1921 by: 1923 1. For each Link Tuple in the Link Set for this OLSRv2 interface 1924 with L_status == SYMMETRIC, and the corresponding Neighbor Tuple 1925 with N_neighbor_iface_addr_list containing 1926 L_neighbor_iface_addr_list: 1928 1. All addresses from L_neighbor_iface_addr_list MUST be 1929 included in the Relay Set of this OLSRv2 interface if 1930 N_mpr_selector == true, and otherwise MAY be so included. 1932 15.2. Populating the Advertised Neighbor Set 1934 The Advertised Neighbor Set of a node contains all interface 1935 addresses of those symmetric 1-hop neighbors to which the node 1936 advertises a link in its TC messages. This set MUST include all 1937 addresses in all MPR selector of this node. 1939 The Advertised Neighbor Set for this node is thus created by: 1941 1. For each Neighbor Tuple with N_symmetric == true: 1943 1. All addresses from N_neighbor_iface_addr_list MUST be 1944 included in the Advertised Neighbor Set if N_mpr_selector == 1945 true, and otherwise MAY be so included. 1947 Whenever address(es) are added to or removed from the Advertised 1948 Neighbor Set, its ANSN MUST be incremented. 1950 16. Routing Set Calculation 1952 The Routing Set of a node is populated with Routing Tuples that 1953 represent paths from that node to all destinations in the network. 1954 These paths are calculated based on the Network Topology Graph, which 1955 is constructed from information in the Information Bases, obtained 1956 via HELLO and TC message exchange. 1958 16.1. Network Topology Graph 1960 The Network Topology Graph is formed from information from the node's 1961 Link Sets, Neighbor Set, Topology Set and Attached Network Set. The 1962 Network Topology Graph SHOULD also use information from the node's 1963 2-Hop Sets. The Network Topology Graph forms that node's topological 1964 view of the network in form of a directed graph, containing the 1965 following arcs: 1967 o Local symmetric links - all arcs X -> Y such that: 1969 * X is an address in the I_local_iface_addr_list of a Local 1970 Interface Tuple of this node, AND; 1972 * Y is an address in the L_neighbor_iface_addr_list of a Link 1973 Tuple in the corresponding (to the OLSRv2 interface of that 1974 I_local_iface_addr_list) Link Set which has L_status == 1975 SYMMETRIC. 1977 o 2-hop symmetric links - all arcs Y -> Z such that: 1979 * Y is an address in the L_neighbor_iface_addr_list of a Link 1980 Tuple, in any of the node's Link Sets, which has L_status == 1981 SYMMETRIC, AND; 1983 * the Neighbor Tuple with Y in its N_neighbor_iface_addr_list has 1984 N_willingness not equal to WILL_NEVER, AND; 1986 * Z is the N2_2hop_iface_addr of a 2-Hop Tuple in the 2-Hop Set 1987 corresponding to the OLSRv2 interface of the chosen Link Set. 1989 o Advertised symmetric links - all arcs U -> V such that there 1990 exists a Topology Tuple and a corresponding Advertising Remote 1991 Node Tuple (i.e. with AR_orig_addr == T_orig_addr) with: 1993 * U is in the AR_iface_addr_list of the Advertising Remote Node 1994 Tuple, AND; 1996 * V is the T_dest_iface_addr of the Topology Tuple. 1998 o Symmetric 1-hop neighbor addresses - all arcs Y -> W such that: 2000 * Y is, and W is not, an address in the 2001 L_neighbor_iface_addr_list of a Link Tuple, in any of the 2002 node's Link Sets, which has L_status == SYMMETRIC, AND; 2004 * W and Y are included in the same N_neighbor_iface_addr_list 2005 (i.e. the one in the Neighbor Tuple whose 2006 N_neighbor_iface_addr_list contains the 2007 L_neighbor_iface_addr_list that includes Y). 2009 o Attached network addresses - all arcs U -> T such that there 2010 exists an Attached Network Tuple and a corresponding Advertising 2011 Remote Node Tuple (i.e. with AR_orig_addr == AN_orig_addr) with: 2013 * U is in the AR_iface_addr_list of the Advertising Remote Node 2014 Tuple, AND; 2016 * T is the AN_net_addr of the Attached Network Tuple. 2018 All links in the first three cases above have a hop count of one, the 2019 symmetric 1-hop neighbor addresses have a hop count of zero, and the 2020 attached network addresses have a hop count given by the appropriate 2021 value of AN_dist. 2023 16.2. Populating the Routing Set 2025 The Routing Set MUST contain the shortest paths for all destinations 2026 from all local OLSRv2 interfaces using the Network Topology Graph. 2027 This calculation MAY use any algorithm, including any means of 2028 choosing between paths of equal length. 2030 Using the notation of Section 16.1, each path will have as its first 2031 arc a local symmetric link X -> Y. There will be a path for each 2032 terminating Y, Z, V, W and T which can be connected to local OLSRv2 2033 interface address X using the indicated arcs. The corresponding 2034 Routing Tuple for this path will have: 2036 o R_dest_addr = the terminating Y, Z, V, W or T; 2038 o R_next_iface_addr = the first arc's Y; 2040 o R_dist = the total hop count of the path; 2042 o R_local_iface_addr = the first arc's X. 2044 An example algorithm for calculating the Routing Set of a node is 2045 given in Appendix C. 2047 16.3. Routing Set Updates 2049 The Routing Set MUST be updated when changes in the Neighborhood 2050 Information Base or the Topology Information Base indicate a change 2051 of the known symmetric links and/or attached networks in the MANET. 2052 It is sufficient to consider only changes which affect at least one 2053 of: 2055 o The Link Set of any OLSRv2 interface, and to consider only Link 2056 Tuples which have, or just had, L_status == SYMMETRIC (including 2057 removal of such Link Tuples). 2059 o The Neighbor Set of the node, and to consider only Neighbor Tuples 2060 that have, or just had, N_symmetric == true. 2062 o The 2-Hop Set of any OLSRv2 interface. 2064 o The Advertising Remote Node Set of the node. 2066 o The Topology Set of the node. 2068 o The Attached Network Set of the node. 2070 Updates to the Routing Set do not generate or trigger any messages to 2071 be transmitted. The state of the Routing Set SHOULD, however, be 2072 reflected in the IP routing table by adding and removing entries from 2073 the IP routing table as appropriate. 2075 17. Proposed Values for Parameters and Constants 2077 OLSRv2 uses all parameters and constants defined in [nhdp] and 2078 additional parameters and constants defined in this document. All 2079 but one (RX_HOLD_TIME) of these additional parameters are node 2080 parameters as defined in [nhdp]. These proposed values of the 2081 additional parameters are appropriate to the case where all 2082 parameters (including those defined in [nhdp]) have a single value. 2083 Proposed values for parameters defined in [nhdp] are given in that 2084 document. 2086 17.1. Local History Time Parameters 2088 o O_HOLD_TIME = 30 seconds 2090 17.2. Message Interval Parameters 2092 o TC_INTERVAL = 5 seconds 2094 o TC_MIN_INTERVAL = TC_INTERVAL/4 2096 17.3. Advertised Information Validity Time Parameters 2098 o T_HOLD_TIME = 3 x TC_INTERVAL 2100 o A_HOLD_TIME = T_HOLD_TIME 2102 17.4. Received Message Validity Time Parameters 2104 o RX_HOLD_TIME = 30 seconds 2106 o P_HOLD_TIME = 30 seconds 2108 o F_HOLD_TIME = 30 seconds 2110 17.5. Jitter Time Parameters 2112 o TP_MAXJITTER = HP_MAXJITTER 2114 o TT_MAXJITTER = HT_MAXJITTER 2116 o F_MAXJITTER = TT_MAXJITTER 2118 17.6. Hop Limit Parameter 2120 o TC_HOP_LIMIT = 255 2122 17.7. Willingness Parameter and Constants 2124 o WILLINGNESS = WILL_DEFAULT 2126 o WILL_NEVER = 0 2128 o WILL_DEFAULT = 3 2130 o WILL_ALWAYS = 7 2132 18. Sequence Numbers 2134 Sequence numbers are used in OLSRv2 with the purpose of discarding 2135 "old" information, i.e. messages received out of order. However with 2136 a limited number of bits for representing sequence numbers, wrap- 2137 around (that the sequence number is incremented from the maximum 2138 possible value to zero) will occur. To prevent this from interfering 2139 with the operation of OLSRv2, the following MUST be observed when 2140 determining the ordering of sequence numbers. 2142 The term MAXVALUE designates in the following one more than the 2143 largest possible value for a sequence number. For a 16 bit sequence 2144 number (as are those defined in this specification) MAXVALUE is 2145 65536. 2147 The sequence number S1 is said to be "greater than" the sequence 2148 number S2 if: 2150 o S1 > S2 AND S1 - S2 < MAXVALUE/2 OR 2152 o S2 > S1 AND S2 - S1 > MAXVALUE/2 2154 When sequence numbers S1 and S2 differ by MAXVALUE/2 their ordering 2155 cannot be determined. In this case, which should not occur, either 2156 ordering may be assumed. 2158 Thus when comparing two messages, it is possible - even in the 2159 presence of wrap-around - to determine which message contains the 2160 most recent information. 2162 19. Security Considerations 2164 Currently, OLSRv2 does not specify any special security measures. As 2165 a proactive routing protocol, OLSRv2 makes a target for various 2166 attacks. The various possible vulnerabilities are discussed in this 2167 section. 2169 19.1. Confidentiality 2171 Being a proactive protocol, OLSRv2 periodically MPR floods 2172 topological information to all nodes in the network. Hence, if used 2173 in an unprotected wireless network, the network topology is revealed 2174 to anyone who listens to OLSRv2 control messages. 2176 In situations where the confidentiality of the network topology is of 2177 importance, regular cryptographic techniques, such as exchange of 2178 OLSRv2 control traffic messages encrypted by PGP [RFC4880] or 2179 encrypted by some shared secret key, can be applied to ensure that 2180 control traffic can be read and interpreted by only those authorized 2181 to do so. 2183 19.2. Integrity 2185 In OLSRv2, each node is injecting topological information into the 2186 network through transmitting HELLO messages and, for some nodes, TC 2187 messages. If some nodes for some reason, malicious or malfunction, 2188 inject invalid control traffic, network integrity may be compromised. 2189 Therefore, message authentication is recommended. 2191 Different such situations may occur, for instance: 2193 1. a node generates TC messages, advertising links to non-neighbor 2194 nodes; 2196 2. a node generates TC messages, pretending to be another node; 2198 3. a node generates HELLO messages, advertising non-neighbor nodes; 2200 4. a node generates HELLO messages, pretending to be another node; 2202 5. a node forwards altered control messages; 2204 6. a node does not forward control messages; 2206 7. a node does not select multipoint relays correctly; 2208 8. a node forwards broadcast control messages unaltered, but does 2209 not forward unicast data traffic; 2211 9. a node "replays" previously recorded control traffic from another 2212 node. 2214 Authentication of the originator node for control messages (for 2215 situations 2, 4 and 5) and on the individual links announced in the 2216 control messages (for situations 1 and 3) may be used as a 2217 countermeasure. However to prevent nodes from repeating old (and 2218 correctly authenticated) information (situation 9) temporal 2219 information is required, allowing a node to positively identify such 2220 delayed messages. 2222 In general, digital signatures and other required security 2223 information may be transmitted as a separate OLSRv2 message type, or 2224 signatures and security information may be transmitted within the 2225 OLSRv2 HELLO and TC messages, using the TLV mechanism. Either option 2226 permits that "secured" and "unsecured" nodes can coexist in the same 2227 network, if desired, 2229 Specifically, the authenticity of entire OLSRv2 control packets can 2230 be established through employing IPsec authentication headers, 2231 whereas authenticity of individual links (situations 1 and 3) require 2232 additional security information to be distributed. 2234 An important consideration is that all control messages in OLSRv2 are 2235 transmitted either to all nodes in the neighborhood (HELLO messages) 2236 or broadcast to all nodes in the network (TC messages). 2238 For example, a control message in OLSRv2 is always a point-to- 2239 multipoint transmission. It is therefore important that the 2240 authentication mechanism employed permits that any receiving node can 2241 validate the authenticity of a message. As an analogy, given a block 2242 of text, signed by a PGP private key, then anyone with the 2243 corresponding public key can verify the authenticity of the text. 2245 19.3. Interaction with External Routing Domains 2247 OLSRv2 does, through the use of TC messages, provide a basic 2248 mechanism for injecting external routing information to the OLSRv2 2249 domain. Appendix A also specifies that routing information can be 2250 extracted from the topology table or the routing table of OLSRv2 and, 2251 potentially, injected into an external domain if the routing protocol 2252 governing that domain permits. 2254 Other than as described in Appendix A, when operating nodes 2255 connecting OLSRv2 to an external routing domain, care MUST be taken 2256 not to allow potentially insecure and untrustworthy information to be 2257 injected from the OLSRv2 domain to external routing domains. Care 2258 MUST be taken to validate the correctness of information prior to it 2259 being injected as to avoid polluting routing tables with invalid 2260 information. 2262 A recommended way of extending connectivity from an existing routing 2263 domain to an OLSRv2 routed MANET is to assign an IP prefix (under the 2264 authority of the nodes/gateways connecting the MANET with the exiting 2265 routing domain) exclusively to the OLSRv2 MANET area, and to 2266 configure the gateways statically to advertise routes to that IP 2267 sequence to nodes in the existing routing domain. 2269 20. IANA Considerations 2271 20.1. Message Types 2273 OLSRv2 defines one message type, which must be allocated from the 2274 "Assigned Message Types" repository of [packetbb]. 2276 +------+------+-----------------------------------------+ 2277 | Name | Type | Description | 2278 +------+------+-----------------------------------------+ 2279 | TC | TBD1 | Topology Control (MANET-wide signaling) | 2280 +------+------+-----------------------------------------+ 2282 Table 5 2284 20.2. TLV Types 2286 OLSRv2 defines two message TLV types, which must be allocated from 2287 the "Assigned message TLV Types" repository of [packetbb]. 2289 +--------------+------+----------------+----------------------------+ 2290 | Name | Type | Type extension | Description | 2291 +--------------+------+----------------+----------------------------+ 2292 | MPR_WILLING | TBD2 | 0 | Specifies the originating | 2293 | | | | node's willingness to act | 2294 | | | | as a relay and to partake | 2295 | | | | in network formation | 2296 | | | | | 2297 | | | 1-255 | RESERVED | 2298 | | | | | 2299 | CONT_SEQ_NUM | TBD3 | 0 (COMPLETE) | Specifies a content | 2300 | | | | sequence number for this | 2301 | | | | complete message | 2302 | | | | | 2303 | | | 1 (INCOMPLETE) | Specifies a content | 2304 | | | | sequence number for this | 2305 | | | | incomplete message | 2306 | | | | | 2307 | | | 2-255 | RESERVED | 2308 +--------------+------+----------------+----------------------------+ 2310 Table 6 2312 Type extensions indicated as RESERVED may be allocated by standards 2313 action, as specified in [RFC2434]. 2315 OLSRv2 defines two Address Block TLV types, which must be allocated 2316 from the "Assigned address block TLV Types" repository of [packetbb]. 2318 +---------+------+-----------+--------------------------------------+ 2319 | Name | Type | Type | Description | 2320 | | | extension | | 2321 +---------+------+-----------+--------------------------------------+ 2322 | MPR | TBD4 | 0 | Specifies that a given address is of | 2323 | | | | a node selected as an MPR | 2324 | | | | | 2325 | | | 1-255 | RESERVED | 2326 | | | | | 2327 | GATEWAY | TBD5 | 0 | Specifies that a given address is | 2328 | | | | reached via a gateway on the | 2329 | | | | originating node | 2330 | | | | | 2331 | | | 1-255 | RESERVED | 2332 +---------+------+-----------+--------------------------------------+ 2334 Table 7 2336 Type extensions indicated as RESERVED may be allocated by standards 2337 action, as specified in [RFC2434]. 2339 21. References 2341 21.1. Normative References 2343 [packetbb] Clausen, T., Dean, J., Dearlove, C., and C. Adjih, 2344 "Generalized MANET Packet/Message Format", work in 2345 progress draft-ietf-manet-packetbb-12.txt, March 2008. 2347 [timetlv] Clausen, T. and C. Dearlove, "Representing multi-value 2348 time in MANETs", Work In 2349 Progress draft-ietf-manet-timetlv-04.txt, November 2007. 2351 [RFC5148] Clausen, T., Dearlove, C., and B. Adamson, "Jitter 2352 considerations in MANETs", RFC 5148, February 2008. 2354 [nhdp] Clausen, T., Dean, J., and C. Dearlove, "MANET 2355 Neighborhood Discovery Protocol (NHDP)", work in 2356 progress draft-ietf-manet-nhdp-06.txt, March 2008. 2358 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 2359 Requirement Levels", RFC 2119, BCP 14, March 1997. 2361 [RFC2434] Narten, T. and H. Alvestrand, "Guidelines for Writing an 2362 IANA Considerations Section in RFCs", RFC 2434, BCP 26, 2363 October 1998. 2365 21.2. Informative References 2367 [RFC3626] Clausen, T. and P. Jacquet, "The Optimized Link State 2368 Routing Protocol", RFC 3626, October 2003. 2370 [RFC4880] Callas, J., Donnerhacke, L., Finney, H., and R. Thayer, 2371 "OpenPGP message format", RFC 4880, November 2007. 2373 [HIPERLAN] ETSI, "ETSI STC-RES10 Committee. Radio equipment and 2374 systems: HIPERLAN type 1, functional specifications ETS 2375 300-652", June 1996. 2377 [HIPERLAN2] Jacquet, P., Minet, P., Muhlethaler, P., and N. 2378 Rivierre, "Increasing reliability in cable free radio 2379 LANs: Low level forwarding in HIPERLAN.", 1996. 2381 [MPR] Qayyum, A., Viennot, L., and A. Laouiti, "Multipoint 2382 relaying: An efficient technique for flooding in mobile 2383 wireless networks.", 2001. 2385 [RFC2501] Macker, J. and S. Corson, "Mobile Ad hoc Networking 2386 (MANET): Routing Protocol Performance Issues and 2387 Evaluation Considerations", RFC 2501, January 1999. 2389 [FSR] Pei, G., Gerla, M., and T. Chen, "Fisheye state routing 2390 in mobile ad hoc networks", 2000. 2392 [FSLS] Santivanez, C., Ramanathan, R., and I. Stavrakakis, 2393 "Making link-state routing scale for ad hoc networks", 2394 2000. 2396 Appendix A. Node Configuration 2398 OLSRv2 does not make any assumption about node addresses, other than 2399 that each node is assumed to have at least one unique and routable IP 2400 address for each interface that it has which participates in the 2401 MANET. 2403 When applicable, a recommended way of connecting an OLSRv2 network to 2404 an existing IP routing domain is to assign an IP prefix (under the 2405 authority of the nodes/gateways connecting the MANET with the routing 2406 domain) exclusively to the OLSRv2 area, and to configure the gateways 2407 statically to advertise routes to that IP sequence to nodes in the 2408 existing routing domain. 2410 Appendix B. Example Algorithm for Calculating MPRs 2412 The following specifies an algorithm which MAY be used to select 2413 MPRs. MPRs are calculated per OLSRv2 interface, but then a single 2414 set of MPRs is formed from the union of the MPRs for all OLSRv2 2415 interfaces. (As noted in Section 14 a node MAY improve on this, by 2416 coordination between OLSRv2 interfaces.) A node's MPRs are recorded 2417 using the element N_mpr in Neighbor Tuples. 2419 If using this algorithm then the following steps MUST be executed in 2420 order for a node to select its MPRs: 2422 1. Set N_mpr = false in all Neighbor Tuples; 2424 2. For each Neighbor Tuple with N_symmetric == true and 2425 N_willingness == WILL_ALWAYS, set N_mpr = true; 2427 3. For each OLSRv2 interface of the node, use the algorithm in 2428 Appendix B.2. Note that this sets N_mpr = true for some Neighbor 2429 Tuples, these nodes are already selected as MPRs when using the 2430 algorithm for following OLSRv2 interfaces. 2432 4. OPTIONALLY, consider each selected MPR in turn, and if the set of 2433 selected MPRs without that node still satisfies the necessary 2434 conditions, for all OLSRv2 interfaces, then that node MAY be 2435 removed from the set of MPRs. This process MAY be repeated until 2436 no MPRs are removed. Nodes MAY be considered in order of 2437 increasing N_willingness. 2439 Symmetric 1-hop neighbor nodes with N_willingness == WILL_NEVER MUST 2440 NOT be selected as MPRs, and MUST be ignored in the following 2441 algorithm, as MUST be symmetric 2-hop neighbor nodes which are also 2442 symmetric 1-hop neighbor nodes (i.e. when considering 2-Hop Tuples, 2443 ignore any 2-Hop Tuples whose N2_2hop_iface_addr is in the 2444 N_neighbor_iface_addr_list of any Neighbor Tuple, or whose 2445 N2_neighbor_iface_addr_list is included in the 2446 N_neighbor_iface_addr_list of any Neighbor Tuple with N_willingness 2447 == WILL_NEVER). 2449 B.1. Terminology 2451 The following terminology will be used when selecting MPRs for the 2452 OLSRv2 interface I: 2454 N(I) - The set of symmetric 1-hop neighbors which have a symmetric 2455 link to I. 2457 N2(I) - The set of addresses of interfaces of a node with a 2458 symmetric link to a node in N(I); this MAY be restricted to 2459 considering only information received over I (in which case N2(I) 2460 is the set of N2_2hop_iface_addr in 2-Hop Tuples in the 2-Hop Set 2461 for OLSRv2 interface I). 2463 Connected to I via Y - An address A in N2(I) is connected to I via a 2464 node Y in N(I) if A is an address of an interface of a symmetric 2465 1-hop neighbor of Y (i.e. A is the N2_2hop_iface_addr in a 2-Hop 2466 Tuple in the 2-Hop Set for OLSRv2 interface I, and whose 2467 N2_neighbor_iface_addr_list is contained in the set of interface 2468 addresses of Y). 2470 D(Y, I) - For a node Y in N(I), the number of addresses in N2(I) 2471 which are connected to I via Y. 2473 R(Y, I): - For a node Y in N(I), the number of addresses in N2(I) 2474 which are connected to I via Y, but are not connected to I via any 2475 node which has already been selected as an MPR. 2477 B.2. MPR Selection Algorithm for each OLSRv2 Interface 2479 When selecting MPRs for the OLSRv2 interface I: 2481 1. For each address A in N2(I) for which there is only one node Y in 2482 N(I) such that A is connected to I via Y, select that node Y as 2483 an MPR (i.e. set N_mpr = true in the Neighbor Tuple corresponding 2484 to Y). 2486 2. While there exists any node Y in N(I) with R(Y, I) > 0: 2488 1. Select a node Y in N(I) with R(Y, I) > 0 in the following 2489 order of priority: 2491 + greatest N_willingness in the Neighbor Tuple corresponding 2492 to Y, THEN; 2494 + greatest R(Y, I), THEN; 2496 + greatest D(Y, I), THEN; 2498 + N_mpr_selector is equal to true, if possible, THEN; 2500 + any choice. 2502 2. Select Y as an MPR (i.e. set N_mpr = true in the Neighbor 2503 Tuple corresponding to Y). 2505 Appendix C. Example Algorithm for Calculating the Routing Set 2507 The following procedure is given as an example for calculating the 2508 Routing Set using a variation of Dijkstra's algorithm. First all 2509 Routing Tuples are removed, and then the procedures in the following 2510 sections are applied in turn. 2512 C.1. Add Local Symmetric Links 2514 1. For each Local Interface Tuple in the Local Interface Set: 2516 1. For each address A in I_local_iface_addr_list: 2518 1. For each Link Tuple in the Link Set for this local 2519 interface, with L_status == SYMMETRIC: 2521 1. For each address, B, in that Link Tuple's 2522 L_neighbor_iface_addr_list, add a new Routing Tuple 2523 with: 2525 o R_dest_addr = B; 2527 o R_next_iface_addr = B; 2529 o R_dist = 1; 2531 o R_local_iface_addr = A. 2533 2. For each Neighbor Tuple, for which there is an address B in 2534 N_neighbor_iface_addr_list, for which there is a Routing Tuple 2535 (the "previous Routing Tuple") with R_dest_addr == B: 2537 1. For each address C in N_neighbor_iface_addr_list for which 2538 there is no Routing Tuple with R_dest_addr == C, add a 2539 Routing Tuple with: 2541 + R_dest_addr = C; 2543 + R_next_iface_addr = B; 2545 + R_dist = 1; 2547 + R_local_iface_addr = R_local_iface_addr of the previous 2548 Routing Tuple. 2550 C.2. Add Remote Symmetric Links 2552 The following procedure, which adds Routing Tuples for destination 2553 nodes h+1 hops away, MUST be executed for each value of h, starting 2554 with h = 1 and incrementing by 1 for each iteration. The execution 2555 MUST stop if no new Routing Tuples are added in an iteration. 2557 1. For each Topology Tuple, if: 2559 * T_dest_iface_addr is not equal to R_dest_addr of any Routing 2560 Tuple, AND; 2562 * for the Advertising Remote Node Tuple with AR_orig_addr == 2563 T_orig_addr, there is an address in the AR_iface_addr_list 2564 which is equal to the R_dest_addr of a Routing Tuple (the 2565 "previous Routing Tuple") whose R_dist == h 2567 then add a new Routing Tuple, with: 2569 * R_dest_addr = T_dest_iface_addr; 2571 * R_next_iface_addr = R_next_iface_addr of the previous Routing 2572 Tuple; 2574 * R_dist = h+1; 2576 * R_local_iface_addr = R_local_iface_addr of the previous 2577 Routing Tuple. 2579 More than one Topology Tuple may be usable to select the next hop 2580 R_next_iface_addr for reaching the address R_dest_addr. Ties 2581 should be broken such that nodes with greater willingness are 2582 preferred, and between nodes of equal willingness, MPR selectors 2583 are preferred over non-MPR selectors. 2585 2. After the above iteration has completed, if h == 1, for each 2586 2-Hop Neighbor Tuple where: 2588 * N2_2hop_iface_addr is not equal to R_dest_addr of any Routing 2589 Tuple, AND; 2591 * The Neighbor Tuple whose N_neighbor_iface_addr_list contains 2592 N2_neighbor_iface_addr_list has N_willingness not equal to 2593 WILL_NEVER 2595 select a Routing Tuple (the "previous Routing Tuple") whose 2596 R_dest_addr is contained in N2_neighbor_iface_addr_list, and add 2597 a new Routing Tuple with: 2599 * R_dest_addr = N2_2hop_iface_addr; 2601 * R_next_iface_addr = R_next_iface_addr of the previous Routing 2602 Tuple; 2604 * R_dist = 2; 2606 * R_local_iface_addr = R_local_iface_addr of the previous 2607 Routing Tuple. 2609 More than one 2-Hop Neighbor Tuple may be usable to select the 2610 next hop R_next_iface_addr for reaching the address R_dest_addr. 2611 Ties should be broken such that nodes with greater willingness 2612 are preferred, and between nodes of equal willingness, MPR 2613 selectors are preferred over non-MPR selectors. 2615 C.3. Add Attached Networks 2617 1. For each Attached Network Tuple, if for the Advertising Remote 2618 Node Tuple with AR_orig_addr == AN_orig_addr, there is an address 2619 in the AR_iface_addr_list which is equal to the R_dest_addr of a 2620 Routing Tuple (the "previous Routing Tuple"), then: 2622 1. If there is no Routing Tuple with R_dest_addr == AN_net_addr, 2623 then add a new Routing Tuple with: 2625 + R_dest_addr = AN_net_addr; 2627 + R_next_iface_addr = R_next_iface_addr of the previous 2628 Routing Tuple; 2630 + R_dist = (R_dist of the previous Routing Tuple) + AN_dist; 2632 + R_local_iface_addr = R_local_iface_addr of the previous 2633 Routing Tuple. 2635 2. Otherwise if the Routing Tuple with R_dest_addr == 2636 AN_net_addr (the "current Routing Tuple") has R_dist > 2637 (R_dist of the previous Routing Tuple) + AN_dist, then modify 2638 the current Routing Tuple by: 2640 + R_next_iface_addr = R_next_iface_addr of the previous 2641 Routing Tuple; 2643 + R_dist = (R_dist of the previous Routing Tuple) + AN_dist; 2645 + R_local_iface_addr = R_local_iface_addr of the previous 2646 Routing Tuple. 2648 Appendix D. Example Message Layout 2650 An example TC message, using IPv4 (four octet) addresses, is as 2651 follows. The overall message length is 65 octets. 2653 The message has semantics octet 30, and hence all required message 2654 header fields. It has a message TLV block with content length 13 2655 octets containing three TLVs. The first two TLVs are validity and 2656 interval times for the message. The third TLV is the content 2657 sequence number TLV used to carry the 2 octet ANSN, and (with default 2658 type extension zero, i.e. COMPLETE) indicating that the TC message 2659 is complete. Each TLV uses a TLV with semantics value 8, indicating 2660 that it has a value, but no type extension or start and stop indexes. 2661 The first two TLVs have a value length of 1 octet, the last has a 2662 value length of 2 octets. 2664 The message has two address blocks. The first address block contains 2665 6 addresses, with semantics octet 1, hence with a head section, (with 2666 length 2 octets) but no tail section, and hence mid sections with 2667 length two octets. The following TLV block (content length 6 octets) 2668 contains a single LOCAL_IF TLV (semantics value 12) indicating that 2669 the first three addresses (indexes 0 to 2) are associated with the 2670 value (length 1 octet) UNSPEC_IF, i.e. they are the originating 2671 node's local interface addresses. The remaining three addresses have 2672 no associated TLV, they are the interface addresses of advertised 2673 neighbors. 2675 The second address block contains 1 address, with semantics octet 13 2676 indicating that there is a head section (with length 2 octets), that 2677 the tail section (length 2 octets) consists of zero valued octets 2678 (not included), and that there is a single prefix length, which is 2679 16. The network address is thus Head.0.0/16. The following TLV 2680 block (content length 8 octets) includes one TLV that indicates that 2681 the originating node is a gateway to this network, at a given number 2682 of hops distance (value length 1 octet). The TLV semantics value of 2683 8 indicates that no indexes are needed. 2685 0 1 2 3 2686 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2687 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2688 | TC |0 0 0 1 1 1 1 0|0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 1| 2689 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2690 | Originator Address | 2691 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2692 | Hop Limit | Hop Count | Message Sequence Number | 2693 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2694 |0 0 0 0 0 0 0 0 0 0 0 0 1 1 0 1| VALIDITY_TIME |0 0 0 0 1 0 0 0| 2695 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2696 |0 0 0 0 0 0 0 1| Value | INTERVAL_TIME |0 0 0 0 1 0 0 0| 2697 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2698 |0 0 0 0 0 0 0 1| Value | CONT_SEQ_NUM |0 0 0 0 1 0 0 0| 2699 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2700 |0 0 0 0 0 0 1 0| Value (ANSN) |0 0 0 0 0 1 1 0| 2701 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2702 |0 0 0 0 0 0 0 1|0 0 0 0 0 0 1 0| Head | 2703 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2704 | Mid | Mid | 2705 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2706 | Mid | Mid | 2707 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2708 | Mid | Mid | 2709 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2710 |0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 0| LOCAL_IF |0 0 0 0 1 1 0 0| 2711 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2712 |0 0 0 0 0 0 0 0|0 0 0 0 0 0 1 0|0 0 0 0 0 0 0 1| UNSPEC_IF | 2713 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2714 |0 0 0 0 0 0 0 1|0 0 0 0 1 1 0 1|0 0 0 0 0 0 1 0| Head | 2715 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2716 | Head (cont) |0 0 0 0 0 0 1 0|0 0 0 1 0 0 0 0|0 0 0 0 0 0 0 0| 2717 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2718 |0 0 0 0 0 1 0 0| GATEWAY |0 0 0 0 1 0 0 0|0 0 0 0 0 0 0 1| 2719 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2720 | Number Hops | 2721 +-+-+-+-+-+-+-+-+ 2723 Appendix E. Constraints 2725 Any process which updates the Local Information Base, the 2726 Neighborhood Information Base or the Topology Information Base MUST 2727 ensure that all constraints specified in this appendix are 2728 maintained, as well as those specified in [nhdp]. 2730 In each Originator Tuple: 2732 o O_orig_addr MUST NOT equal any other O_orig_addr. 2734 o O_orig_addr MUST NOT equal this node's originator address. 2736 In each Local Attached Network Tuple: 2738 o AL_net_addr MUST NOT equal any other AL_net_addr. 2740 o AL_net_addr MUST NOT be in the I_local_iface_addr_list of any 2741 Local Interface Tuple or be equal to the IR_local_iface_addr of 2742 any Removed Interface Address Tuple. 2744 o AL_dist MUST NOT be less than zero. 2746 In each Link Tuple: 2748 o L_neighbor_iface_addr_list MUST NOT contain the AL_net_addr of any 2749 Local Attached Network Tuple. 2751 o If L_status == SYMMETRIC and the Neighbor Tuple whose 2752 N_neighbor_iface_addr_list contains L_neighbor_iface_addr_list has 2753 N_mpr_selector == true, then, for each address in this 2754 L_neighbor_iface_addr_list, there MUST be an equal 2755 RY_neighbor_iface_addr in the Relay Set associated with the same 2756 OLSRv2 interface. 2758 In each Neighbor Tuple: 2760 o N_neighbor_iface_addr_list MUST NOT contain the AL_net_addr of any 2761 Local Attached Network Tuple. 2763 o If N_willingness MUST be in the range from WILL_NEVER to 2764 WILL_ALWAYS, inclusive. 2766 o If N_mpr == true, then N_symmetric MUST be true and N_willingness 2767 MUST NOT equal WILL_NEVER. 2769 o If N_symmetric == true and N_mpr == false, then N_willingness MUST 2770 NOT equal WILL_ALWAYS. 2772 o If N_mpr_selector == true, then N_symmetric MUST be true. 2774 o If N_mpr_selector == true, then, for each address in this 2775 N_neighbor_iface_addr_list, there MUST be an equal 2776 A_neighbor_iface_addr in the Advertised Neighbor Set. 2778 In each Lost Neighbor Tuple: 2780 o NL_neighbor_iface_addr MUST NOT equal the AL_net_addr of any Local 2781 Attached Network Tuple. 2783 In each 2-Hop Tuple: 2785 o N2_2hop_iface_addr MUST NOT equal the AL_net_addr of any Local 2786 Attached Network Tuple. 2788 In each Received Tuple: 2790 o RX_orig_addr MUST NOT equal this node's originator address or any 2791 O_orig_addr. 2793 o Each ordered triple (RX_type, RX_orig_addr, RX_seq_number) MUST 2794 NOT equal the corresponding triple in any other Received Tuple in 2795 the same Received Set. 2797 In each Processed Tuple: 2799 o P_orig_addr MUST NOT equal this node's originator address or any 2800 O_orig_addr. 2802 o Each ordered triple (P_type, P_orig_addr, P_seq_number) MUST NOT 2803 equal the corresponding triple in any other Processed Tuple. 2805 In each Forwarded Tuple: 2807 o F_orig_addr MUST NOT equal this node's originator address or any 2808 O_orig_addr. 2810 o Each ordered triple (F_type, F_orig_addr, F_seq_number) MUST NOT 2811 equal the corresponding triple in any other Forwarded Tuple. 2813 In each Relay Tuple: 2815 o RY_neighbor_iface_addr MUST NOT equal the RY_neighbor_iface_addr 2816 in any other Relay Tuple in the same Relay Set. 2818 o RY_neighbor_iface_addr MUST be in the L_neighbor_iface_addr_list 2819 of a Link Tuple with L_status == SYMMETRIC. 2821 In the Advertised Neighbor Set: 2823 o Each A_neighbor_iface_addr MUST NOT equal any other 2824 A_neighbor_iface_addr. 2826 o Each A_neighbor_iface_addr MUST be in the 2827 N_neighbor_iface_addr_list of a Neighbor Tuple with N_symmetric == 2828 true. 2830 In each Advertising Remote Node Tuple: 2832 o AR_orig_addr MUST NOT equal this node's originator address or any 2833 O_orig_addr. 2835 o AR_orig_addr MUST NOT equal the AR_orig_addr in any other ANSN 2836 History Tuple. 2838 o AR_iface_addr_list MUST NOT be empty. 2840 o AR_iface_addr_list MUST NOT contain any duplicated addresses. 2842 o AR_iface_addr_list MUST NOT contain any address which is in the 2843 I_local_iface_addr_list of any Local Interface Tuple or be equal 2844 to the IR_local_iface_addr of any Removed Interface Address Tuple. 2846 o AR_iface_addr_list MUST NOT contain any address which is the 2847 AL_net_addr of any Local Attached Network Tuple. 2849 In each Topology Tuple: 2851 o T_dest_iface_addr MUST NOT be in the I_local_iface_addr_list of 2852 any Local Interface Tuple or be equal to the IR_local_iface_addr 2853 of any Removed Interface Address Tuple. 2855 o T_dest_iface_addr MUST NOT equal the AL_net_addr of any Local 2856 Attached Network Tuple. 2858 o There MUST be an Advertising Remote Node Tuple with AR_orig_addr 2859 == T_orig_addr. 2861 o T_dest_iface_addr MUST NOT be in the AR_iface_addr_list of the 2862 Advertising Remote Node Tuple with AR_orig_addr == T_orig_addr. 2864 o T_seq_number MUST NOT be greater than AR_seq_number of the 2865 Advertising Remote Node Tuple with AR_orig_addr == T_orig_addr. 2867 o The ordered pair (T_dest_iface_addr, T_orig_addr) MUST NOT equal 2868 the corresponding pair in any other Topology Tuple. 2870 In each Attached Network Tuple: 2872 o AN_net_addr MUST NOT be in the I_local_iface_addr_list of any 2873 Local Interface Tuple or be equal to the IR_local_iface_addr of 2874 any Removed Interface Address Tuple. 2876 o AN_net_addr MUST NOT equal the AL_net_addr of any Local Attached 2877 Network Tuple. 2879 o There MUST be an Advertising Remote Node Tuple with AR_orig_addr 2880 == AN_orig_addr. 2882 o AN_seq_number MUST NOT be greater than AR_seq_number of the 2883 Advertising Remote Node Tuple with AR_orig_addr == AN_orig_addr. 2885 o AN_dist MUST NOT be less than zero. 2887 o The ordered pair (AN_net_addr, AN_orig_addr) MUST NOT equal the 2888 corresponding pair in any other Attached Network Tuple. 2890 Appendix F. Flow and Congestion Control 2892 Due to its proactive nature, the OLSRv2 protocol has a natural 2893 control over the flow of its control traffic. Nodes transmit control 2894 messages at predetermined rates specified and bounded by message 2895 intervals. 2897 OLSRv2 employs [nhdp] for local signaling, embedding MPR selection 2898 advertisement through a simple address block TLV, and node 2899 willingness advertisement (if any) as a single message TLV. OLSRv2 2900 local signaling, therefore, shares the characteristics and 2901 constraints of [nhdp]. 2903 Furthermore, MPR flooding greatly reduces signaling overhead from 2904 from link state information dissemination in two ways. First, the 2905 amount of link state information for a node to declare is reduced to 2906 only contain that node's MPR selectors. This reduces the size of a 2907 link state declaration as compared to declaring full link state 2908 information. In particular some nodes may not need to declare any 2909 such information. Second, using MPR flooding, the cost of 2910 distributing link state information throughout the network is greatly 2911 reduced, as compared to when using classic flooding, since only MPRs 2912 need to forward link state declaration messages. In dense networks, 2913 the reduction of control traffic can be of several orders of 2914 magnitude compared to routing protocols using classical flooding 2915 [MPR]. This feature naturally provides more bandwidth for useful 2916 data traffic and pushes further the frontier of congestion. 2918 Since the control traffic is continuous and periodic, it keeps the 2919 quality of the links used in routing more stable. However, using 2920 certain OLSRv2 options, some control messages (HELLO messages or TC 2921 messages) may be intentionally sent in advance of their deadline in 2922 order to increase the responsiveness of the protocol to topology 2923 changes. This may cause a small, temporary, and local increase of 2924 control traffic, however this is at all times bounded by the use of 2925 minimum message intervals. 2927 Appendix G. Contributors 2929 This specification is the result of the joint efforts of the 2930 following contributors -- listed alphabetically. 2932 o Cedric Adjih, INRIA, France, 2934 o Emmanuel Baccelli, INRIA , France, 2936 o Thomas Heide Clausen, LIX, France, 2938 o Justin Dean, NRL, USA, 2940 o Christopher Dearlove, BAE Systems, UK, 2941 2943 o Satoh Hiroki, Hitachi SDL, Japan, 2945 o Philippe Jacquet, INRIA, France, 2947 o Monden Kazuya, Hitachi SDL, Japan, 2949 o Kenichi Mase, Niigata University, Japan, 2951 o Ryuji Wakikawa, KEIO University, Japan, 2953 Appendix H. Acknowledgements 2955 The authors would like to acknowledge the team behind OLSRv1, 2956 specified in RFC3626, including Anis Laouiti (INT, Paris), Pascale 2957 Minet (INRIA, France), Laurent Viennot (INRIA, France), and Amir 2958 Qayyum (M.A. Jinnah University, Islamabad) for their contributions. 2960 The authors would like to gratefully acknowledge the following people 2961 for intense technical discussions, early reviews and comments on the 2962 specification and its components: Li Li (CRC), Louise Lamont (CRC), 2963 Joe Macker (NRL), Alan Cullen (BAE Systems), Khaldoun Al Agha (LRI), 2964 Richard Ogier (SRI), Song-Yean Cho (LIX), Shubhranshu Singh (Samsung 2965 AIT), Charles E. Perkins, and the entire IETF MANET working group. 2967 Authors' Addresses 2969 Thomas Heide Clausen 2970 LIX, Ecole Polytechnique, France 2972 Phone: +33 6 6058 9349 2973 EMail: T.Clausen@computer.org 2974 URI: http://www.ThomasClausen.org/ 2976 Christopher Dearlove 2977 BAE Systems Advanced Technology Centre 2979 Phone: +44 1245 242194 2980 EMail: chris.dearlove@baesystems.com 2981 URI: http://www.baesystems.com/ 2983 Philippe Jacquet 2984 Project Hipercom, INRIA 2986 Phone: +33 1 3963 5263 2987 EMail: philippe.jacquet@inria.fr 2989 The OLSRv2 Design Team 2990 MANET Working Group 2992 Full Copyright Statement 2994 Copyright (C) The IETF Trust (2008). 2996 This document is subject to the rights, licenses and restrictions 2997 contained in BCP 78, and except as set forth therein, the authors 2998 retain all their rights. 3000 This document and the information contained herein are provided on an 3001 "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS 3002 OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY, THE IETF TRUST AND 3003 THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS 3004 OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF 3005 THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED 3006 WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. 3008 Intellectual Property 3010 The IETF takes no position regarding the validity or scope of any 3011 Intellectual Property Rights or other rights that might be claimed to 3012 pertain to the implementation or use of the technology described in 3013 this document or the extent to which any license under such rights 3014 might or might not be available; nor does it represent that it has 3015 made any independent effort to identify any such rights. 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