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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: August 28, 2008 BAE Systems Advanced Technology 6 Centre 7 P. Jacquet 8 Project Hipercom, INRIA 9 The OLSRv2 Design Team 10 MANET Working Group 11 February 25, 2008 13 The Optimized Link State Routing Protocol version 2 14 draft-ietf-manet-olsrv2-05 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 August 28, 2008. 41 Copyright Notice 43 Copyright (C) The IETF Trust (2008). 45 Abstract 47 This document describes version 2 of the Optimized Link State Routing 48 (OLSRv2) protocol for mobile ad hoc networks. The protocol embodies 49 an optimization of the classical link state algorithm tailored to the 50 requirements of a mobile ad hoc network (MANET). 52 The key optimization of OLSRv2 is that of multipoint relays, 53 providing an efficient mechanism for network-wide broadcast of link 54 state information (i.e. reducing the cost of performing a network- 55 wide link state broadcast). A secondary optimization is that OLSRv2 56 employs partial link state information: each node maintains 57 information about all destinations, but only a subset of links. 58 Consequently, only selected nodes diffuse link state advertisements 59 (thus reducing the number of network-wide link state broadcasts) and 60 these advertisements contain only a subset of links (thus reducing 61 the size of network-wide link state broadcasts). The partial link 62 state information thus obtained still allows each OLSRv2 node to at 63 all times maintain optimal (in terms of number of hops) routes to all 64 destinations in the network. 66 OLSRv2 imposes minimum requirements on the network by not requiring 67 sequenced or reliable transmission of control traffic. Furthermore, 68 the only interaction between OLSRv2 and the IP stack is routing table 69 management. 71 OLSRv2 is particularly suitable for large and dense networks as the 72 technique of MPRs works well in this context. 74 Table of Contents 76 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 6 77 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 7 78 3. Applicability Statement . . . . . . . . . . . . . . . . . . . 9 79 4. Protocol Overview and Functioning . . . . . . . . . . . . . . 10 80 5. Protocol Parameters and Constants . . . . . . . . . . . . . . 13 81 5.1. Local History Times . . . . . . . . . . . . . . . . . . . 13 82 5.2. Message Intervals . . . . . . . . . . . . . . . . . . . . 13 83 5.3. Advertised Information Validity Times . . . . . . . . . . 14 84 5.4. Received Message Validity Times . . . . . . . . . . . . . 15 85 5.5. Jitter . . . . . . . . . . . . . . . . . . . . . . . . . . 16 86 5.6. Hop Limit Parameter . . . . . . . . . . . . . . . . . . . 16 87 5.7. Willingness . . . . . . . . . . . . . . . . . . . . . . . 16 88 5.8. Parameter Change Constraints . . . . . . . . . . . . . . . 17 89 6. Information Bases . . . . . . . . . . . . . . . . . . . . . . 19 90 6.1. Local Information Base . . . . . . . . . . . . . . . . . . 19 91 6.1.1. Originator Set . . . . . . . . . . . . . . . . . . . . 20 92 6.1.2. Local Attached Network Set . . . . . . . . . . . . . . 20 93 6.2. Node Information Base . . . . . . . . . . . . . . . . . . 20 94 6.3. Topology Information Base . . . . . . . . . . . . . . . . 21 95 6.3.1. Advertised Neighbor Set . . . . . . . . . . . . . . . 21 96 6.3.2. Advertising Remote Node Set . . . . . . . . . . . . . 21 97 6.3.3. Topology Set . . . . . . . . . . . . . . . . . . . . . 22 98 6.3.4. Attached Network Set . . . . . . . . . . . . . . . . . 22 99 6.3.5. Routing Set . . . . . . . . . . . . . . . . . . . . . 23 100 6.4. Processing and Forwarding Information Base . . . . . . . . 23 101 6.4.1. Received Set . . . . . . . . . . . . . . . . . . . . . 23 102 6.4.2. Processed Set . . . . . . . . . . . . . . . . . . . . 24 103 6.4.3. Forwarded Set . . . . . . . . . . . . . . . . . . . . 24 104 6.4.4. Relay Set . . . . . . . . . . . . . . . . . . . . . . 25 105 7. Packet Processing and Message Forwarding . . . . . . . . . . . 26 106 7.1. Actions when Receiving an OLSRv2 Packet . . . . . . . . . 26 107 7.2. Actions when Receiving an OLSRv2 Message . . . . . . . . . 26 108 7.3. Message Considered for Processing . . . . . . . . . . . . 27 109 7.4. Message Considered for Forwarding . . . . . . . . . . . . 28 110 8. Packets and Messages . . . . . . . . . . . . . . . . . . . . . 31 111 8.1. HELLO Messages . . . . . . . . . . . . . . . . . . . . . . 31 112 8.1.1. HELLO Message TLVs . . . . . . . . . . . . . . . . . . 32 113 8.1.2. HELLO Message Address Block TLVs . . . . . . . . . . . 32 114 8.2. TC Messages . . . . . . . . . . . . . . . . . . . . . . . 32 115 8.2.1. TC Message TLVs . . . . . . . . . . . . . . . . . . . 33 116 8.2.2. TC Message Address Block TLVs . . . . . . . . . . . . 34 117 9. HELLO Message Generation . . . . . . . . . . . . . . . . . . . 35 118 9.1. HELLO Message: Transmission . . . . . . . . . . . . . . . 35 119 10. HELLO Message Processing . . . . . . . . . . . . . . . . . . . 36 120 10.1. Updating Willingness . . . . . . . . . . . . . . . . . . . 36 121 10.2. Updating MPR Selectors . . . . . . . . . . . . . . . . . . 36 122 10.3. Symmetric 1-Hop and 2-Hop Neighborhood Changes . . . . . . 36 123 11. TC Message Generation . . . . . . . . . . . . . . . . . . . . 38 124 11.1. TC Message: Transmission . . . . . . . . . . . . . . . . . 39 125 12. TC Message Processing . . . . . . . . . . . . . . . . . . . . 41 126 12.1. Initial TC Message Processing . . . . . . . . . . . . . . 41 127 12.1.1. Populating the Advertising Remote Node Set . . . . . . 42 128 12.1.2. Populating the Topology Set . . . . . . . . . . . . . 43 129 12.1.3. Populating the Attached Network Set . . . . . . . . . 43 130 12.2. Completing TC Message Processing . . . . . . . . . . . . . 44 131 12.2.1. Purging the Topology Set . . . . . . . . . . . . . . . 44 132 12.2.2. Purging the Attached Network Set . . . . . . . . . . . 44 133 13. Information Base Changes . . . . . . . . . . . . . . . . . . . 45 134 14. Selecting MPRs . . . . . . . . . . . . . . . . . . . . . . . . 46 135 15. Populating Derived Sets . . . . . . . . . . . . . . . . . . . 48 136 15.1. Populating the Relay Set . . . . . . . . . . . . . . . . . 48 137 15.2. Populating the Advertised Neighbor Set . . . . . . . . . . 48 138 16. Routing Set Calculation . . . . . . . . . . . . . . . . . . . 49 139 16.1. Network Topology Graph . . . . . . . . . . . . . . . . . . 49 140 16.2. Populating the Routing Set . . . . . . . . . . . . . . . . 50 141 16.3. Routing Set Updates . . . . . . . . . . . . . . . . . . . 51 142 17. Proposed Values for Parameters and Constants . . . . . . . . . 52 143 17.1. Local History Time Parameters . . . . . . . . . . . . . . 52 144 17.2. Message Interval Parameters . . . . . . . . . . . . . . . 52 145 17.3. Advertised Information Validity Time Parameters . . . . . 52 146 17.4. Received Message Validity Time Parameters . . . . . . . . 52 147 17.5. Jitter Time Parameters . . . . . . . . . . . . . . . . . . 52 148 17.6. Hop Limit Parameter . . . . . . . . . . . . . . . . . . . 52 149 17.7. Willingness Parameter and Constants . . . . . . . . . . . 53 150 18. Sequence Numbers . . . . . . . . . . . . . . . . . . . . . . . 54 151 19. Security Considerations . . . . . . . . . . . . . . . . . . . 55 152 19.1. Confidentiality . . . . . . . . . . . . . . . . . . . . . 55 153 19.2. Integrity . . . . . . . . . . . . . . . . . . . . . . . . 55 154 19.3. Interaction with External Routing Domains . . . . . . . . 56 155 20. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 58 156 20.1. Message Types . . . . . . . . . . . . . . . . . . . . . . 58 157 20.2. TLV Types . . . . . . . . . . . . . . . . . . . . . . . . 58 158 21. References . . . . . . . . . . . . . . . . . . . . . . . . . . 60 159 21.1. Normative References . . . . . . . . . . . . . . . . . . . 60 160 21.2. Informative References . . . . . . . . . . . . . . . . . . 60 161 Appendix A. Node Configuration . . . . . . . . . . . . . . . . . 62 162 Appendix B. Example Algorithm for Calculating MPRs . . . . . . . 63 163 B.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 63 164 B.2. MPR Selection Algorithm for each OLSRv2 Interface . . . . 64 165 Appendix C. Example Algorithm for Calculating the Routing Set . . 65 166 C.1. Add Local Symmetric Links . . . . . . . . . . . . . . . . 65 167 C.2. Add Remote Symmetric Links . . . . . . . . . . . . . . . . 66 168 C.3. Add Attached Networks . . . . . . . . . . . . . . . . . . 67 169 Appendix D. Example Message Layout . . . . . . . . . . . . . . . 68 170 Appendix E. Constraints . . . . . . . . . . . . . . . . . . . . . 70 171 Appendix F. Flow and Congestion Control . . . . . . . . . . . . . 74 172 Appendix G. Contributors . . . . . . . . . . . . . . . . . . . . 75 173 Appendix H. Acknowledgements . . . . . . . . . . . . . . . . . . 76 174 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 77 175 Intellectual Property and Copyright Statements . . . . . . . . . . 78 177 1. Introduction 179 The Optimized Link State Routing protocol version 2 (OLSRv2) is an 180 update to OLSRv1 as published in RFC3626 [7]. Compared to RFC3626, 181 OLSRv2 retains the same basic mechanisms and algorithms, while 182 providing a more flexible signaling framework and some simplification 183 of the messages being exchanged. Also, OLSRv2 accommodates either 184 IPv4 and IPv6 addresses in a compact manner. 186 OLSRv2 is developed for mobile ad hoc networks. It operates as a 187 table driven, proactive protocol, i.e. it exchanges topology 188 information with other nodes in the network regularly. Each node 189 selects a set of its neighbor nodes as "MultiPoint Relays" (MPRs). 190 Control traffic may be flooded through the network using hop by hop 191 forwarding, but where a node only needs to forward control traffic 192 directly received from its MPR selectors (nodes which have selected 193 it as an MPR). This mechanism, denoted "MPR flooding", provides an 194 efficient mechanism for global information exchange within the MANET 195 by reducing the number of transmissions required. 197 Nodes selected as MPRs also have a special responsibility when 198 declaring link state information in the network. A sufficient 199 requirement for OLSRv2 to provide shortest (lowest hop count) path 200 routes to all destinations is that nodes declare link state 201 information for their MPR selectors, if any. Additional available 202 link state information may be transmitted, e.g. for redundancy. 203 Thus, as well as being used to facilitate MPR flooding, use of MPRs 204 allows the reduction of the number and size of link state messages, 205 and MPRs are used as intermediate nodes in multi-hop routes. 207 A node selects MPRs from among its one hop neighbors connected by 208 "symmetric", i.e. bi-directional, links. Therefore, selecting routes 209 through MPRs automatically avoids the problems associated with data 210 packet transfer over uni-directional links (such as the problem of 211 not getting link layer acknowledgments at each hop, for link layers 212 employing this technique). 214 OLSRv2 is developed to work independently from other protocols. 215 (Parts of OLSRv2 have been published separately as [1], [2], [3] and 216 [4] for wider use.) Likewise, OLSRv2 makes no assumptions about the 217 underlying link layer. However, OLSRv2 may use link layer 218 information and notifications when available and applicable, as 219 described in [4]. 221 OLSRv2, as OLSRv1, inherits its concept of forwarding and relaying 222 from HIPERLAN (a MAC layer protocol) which is standardized by ETSI 223 [9], [10]. 225 2. Terminology 227 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 228 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 229 document are to be interpreted as described in RFC2119 [5]. 231 MANET specific terminology is to be interpreted as described in [1] 232 and [4]. 234 Additionally, this document uses the following terminology: 236 Node - A MANET router which implements the Optimized Link State 237 Routing protocol version 2 as specified in this document. 239 Willingness - The willingness of a node is a nummerical value 240 between WILL_NEVER and WILL_ALWAYS (both inclusive), which 241 represents the nodes willingess to be selected as an MPR. A node 242 with willingness greater than WILL_NEVER is said to be a "willing 243 node". 245 OLSRv2 interface - A MANET interface, running OLSRv2. Note that all 246 references to MANET interfaces in [4] refer to OLSRv2 interfaces 247 when using [4] as part of OLSRv2. 249 Symmetric strict 2-hop neighbor - A symmetric 2-hop neighbor which 250 is not a symmetric 1-hop neighbor and is not a 2-hop neighbor only 251 through a symmetric 1-hop neighbor with willingness WILL_NEVER. A 252 node Z is a symmetric strict 2-hop neighbor of a node X if it is 253 not a symmetric 1-hop neighbor of node X and if there is a node Y 254 with willingness not equal to WILL_NEVER and such that there is a 255 symmetric link from node X to node Y, and a symmetric link from 256 node Y to node Z. A node Z is a symmetric strict 2-hop neighbor of 257 a node X by an OLSRv2 interface I of node X if in addition the 258 link from node X to node Y uses interface I. 260 Symmetric strict 2-hop neighborhood - The set of the symmetric 261 strict 2-hop neighbors of a node. 263 Multipoint relay (MPR) - A node which is selected by its symmetric 264 1-hop neighbor, node X, to "re-transmit" all the broadcast 265 messages that it receives from node X, provided that the message 266 is not a duplicate, and that the hop limit field of the message is 267 greater than one. 269 MPR selector - A node which has selected its symmetric 1-hop 270 neighbor, node X, as one of its MPRs is an MPR selector of node X. 272 MPR flooding - The optimized global information exchange mechanism, 273 employed by this protocol, in which a message is relayed by only a 274 reduced subset of the nodes in the network. 276 3. Applicability Statement 278 OLSRv2 is a proactive routing protocol for mobile ad hoc networks 279 (MANETs) [12]. The larger and more dense a network, the more 280 optimization can be achieved by using MPRs compared to the classic 281 link state algorithm. OLSRv2 enables hop-by-hop routing, i.e. each 282 node using its local information provided by OLSRv2 to route packets. 284 As OLSRv2 continuously maintains routes to all destinations in the 285 network, the protocol is beneficial for traffic patterns where the 286 traffic is random and sporadic between a large subset of nodes, and 287 where the [source, destination] pairs are changing over time. No 288 additional control traffic need be generated in this case since 289 routes are maintained for all known destinations at all times. Also, 290 since routes are maintained continuously, traffic is subject to no 291 delays due to buffering or to route discovery. 293 OLSRv2 supports nodes which have multiple interfaces which 294 participate in the MANET using OLSRv2. As described in [4], each 295 OLSRv2 interface may have one or more network addresses (which may 296 have prefix lengths). OLSRv2, additionally, supports nodes which 297 have non-OLSRv2 interfaces which may be local or can serve as 298 gateways towards other networks. 300 OLSRv2 uses the format specified in [1] for all messages and packets. 301 OLSRv2 is thereby able to allow for extensions via "external" and 302 "internal" extensibility. External extensibility allows a protocol 303 extension to specify and exchange new message types, which can be 304 forwarded and delivered correctly even by nodes which do not support 305 that extension. Internal extensibility allows a protocol extension 306 to define additional attributes to be carried embedded in the 307 standard OLSRv2 control messages detailed in this specification (or 308 any new message types defined by other protocol extensions) using the 309 TLV mechanism specified in [1], while still allowing nodes not 310 supporting that extension to forward messages including the extension 311 and to process messages ignoring the extension. 313 The OLSRv2 neighborhood discovery protocol using HELLO messages is 314 specified in [4]. This neighborhood discovery protocol serves to 315 ensure that each OLSRv2 node has available continuously updated 316 Information Bases describing the node's 1-hop and symmetric 2-hop 317 neighbors. This neighborhood discovery protocol, which also uses 318 [1], is extended in this document by the addition of MPR information. 320 OLSRv2 does not make any assumption about node addresses, other than 321 that each node is assumed to have at least one unique and routable IP 322 address for each interface that it has which participates in the 323 MANET. 325 4. Protocol Overview and Functioning 327 OLSRv2 is a proactive routing protocol for mobile ad hoc networks. 328 The protocol inherits the stability of a link state algorithm and has 329 the advantage of having routes immediately available when needed due 330 to its proactive nature. OLSRv2 is an optimization of the classical 331 link state protocol, tailored for mobile ad hoc networks. The main 332 tailoring and optimizations of OLSRv2 are: 334 o periodic, unacknowledged transmission of all control messages; 336 o MPR flooding for global link state information declaration; 338 o partial topology maintenance - each node knows only a subset of 339 the links in the network, sufficient for a minimum hop route to 340 all destinations. 342 The MPR flooding and partial topology maintenance are based on the 343 concept on MultiPoint Relays (MPRs), selected independently by nodes 344 based on the symmetric 1-hop and 2-hop neighbor information 345 maintained using [4]. 347 Using the message exchange format [1] and the neighborhood discovery 348 protocol [4], OLSRv2 also contains the following main components: 350 o A TLV, to be included within the HELLO messages of [4], allowing a 351 node to signal MPR selection. 353 o The optimized mechanism for global information exchange, denoted 354 "MPR flooding". 356 o A specification of global signaling, denoted TC (Topology Control) 357 messages. TC messages in OLSRv2 serve to: 359 * inject link state information into the entire network; 361 * inject addresses of hosts and networks for which they may serve 362 as a gateway into the entire network. 364 TC messages are emitted periodically, thereby allowing nodes to 365 continuously track global changes in the network. Incomplete TC 366 messages may be used to report additions to advertised information 367 without repeating unchanged information. Some TC messages may be 368 MPR flooded over only part of the network, allowing a node to 369 ensure that nearer nodes are kept more up to date than distant 370 nodes, such as is used in Fisheye State Routing [13] and Fuzzy- 371 sighted link-state routing [14]. 373 Each node in the network selects a set of MPRs. The MPRs of a node X 374 may be any subset of the willing nodes in node X's symmetric 1-hop 375 neighborhood such that every node in the symmetric strict 2-hop 376 neighborhood of node X has a symmetric link to at least one of node 377 X's MPRs. The MPRs of a node may thus be said to "cover" the node's 378 symmetric strict 2-hop neighborhood. Each node also maintains 379 information about the set of symmetric 1-hop neighbors that have 380 selected it as an MPR, its MPR selectors. 382 As long as the condition above is satisfied, any algorithm selecting 383 MPRs is acceptable in terms of implementation interoperability. 384 However if smaller sets of MPRs are selected then the greater the 385 efficiency gains that are possible. An analysis and examples of MPR 386 selection algorithms is given in [11]. 388 A node may independently determine and advertise its willingness to 389 be selected as an MPR. A node may advertise that it always should be 390 selected as an MPR or that it should never be selected as an MPR. In 391 the latter case, the node will neither relay control messages, nor 392 will that node be included as an intermediate node in any routing 393 table calculations. Use of variable willingness is most effective in 394 dense networks. 396 In OLSRv2, actual efficiency gains are based on the sizes of each 397 node's Relay Set, the set of symmetric 1-hop neighbors for which it 398 is to relay broadcast traffic, and its Advertised Neighbor Set, the 399 set of symmetric 1-hop neighbors for which it is to advertise link 400 state information into the network in TC messages. Each of these 401 sets MUST contain all MPR selectors, and MAY contain additional 402 nodes. If the Advertised Neighbor Set is empty, TC messages are not 403 generated by that node, unless needed for gateway reporting, or for a 404 short period to accelerate the removal of unwanted links. 406 OLSRv2 is designed to work in a completely distributed manner and 407 does not depend on any central entity. The protocol does not require 408 reliable transmission of control messages: each node sends control 409 messages periodically, and can therefore sustain a reasonable loss of 410 some such messages. Such losses may occur frequently in radio 411 networks due to collisions or other transmission problems. OLSRv2 412 MAY use "jitter", randomized adjustments to message transmission 413 times, to reduce the incidence of collisions [3]. 415 OLSRv2 does not require sequenced delivery of messages. Each TC 416 message contains a sequence number which is incremented for each 417 message. Thus the recipient of a TC message can, if required, easily 418 identify which information is more recent - even if messages have 419 been re-ordered while in transmission. 421 OLSRv2 does not require any changes to the format of IP packets, any 422 existing IP stack can be used as is: OLSRv2 only interacts with 423 routing table management. OLSR sends its control messages as 424 described in [1] and [4]. 426 5. Protocol Parameters and Constants 428 The parameters and constants used in this specification are those 429 defined in [4] plus those defined in this section. The separation in 430 [4] into interface parameters, node parameters and constants is also 431 used in OLSRv2, however all but one (RX_HOLD_TIME) of the parameters 432 added by OLSRv2 are node parameters. They may be classified into the 433 following categories: 435 o Local history times 437 o Message intervals 439 o Advertised information validity times 441 o Received message validity times 443 o Jitter times 445 o Hop limits 447 o Willingness 449 In addition constants for particular cases of a node's willingness to 450 be an MPR are defined. These parameters and constants are detailed 451 in the following sections. As for the parameters in [4], parameters 452 defined in this document may be changed dynamically by a node, and 453 need not be the same on different nodes, or on different interfaces 454 (for interface parameters). 456 5.1. Local History Times 458 The following parameter manages the time for which local information 459 is retained: 461 O_HOLD_TIME - is used to define the time for which a recently used 462 and replaced originator address is used to recognise the node's 463 own messages. 465 The following constraint applies to this parameter: 467 o O_HOLD_TIME >= 0 469 5.2. Message Intervals 471 The following interface parameters regulate TC message transmissions 472 by a node. TC messages are usually sent periodically, but MAY also 473 be sent in response to changes in the node's Advertised Neighbor Set 474 and Local Attached Network Set. With a larger value of parameter 475 TC_INTERVAL, and a smaller value of parameter TC_MIN_INTERVAL, TC 476 messages may more often be transmitted in response to changes in a 477 highly dynamic network. However because a node has no knowledge of, 478 for example, nodes remote to it joining the network, TC messages MUST 479 NOT be sent purely responsively. 481 TC_INTERVAL - is the maximum time between the transmission of two 482 successive TC messages by this node. When no TC messages are sent 483 in response to local network changes (by design, or because the 484 local network is not changing) then TC messages SHOULD be sent at 485 a regular interval TC_INTERVAL, possibly modified by jitter as 486 specified in [3]. 488 TC_MIN_INTERVAL - is the minimum interval between transmission of 489 two successive TC messages by this node. (This minimum interval 490 MAY be modified by jitter, as specified in [3].) 492 The following constraints apply to these parameters: 494 o TC_INTERVAL > 0 496 o TC_MIN_INTERVAL >= 0 498 o TC_INTERVAL >= TC_MIN_INTERVAL 500 o If INTERVAL_TIME TLVs as defined in [2] are included in TC 501 messages, then TC_INTERVAL MUST be representable as described in 502 [2]. 504 5.3. Advertised Information Validity Times 506 The following parameters manage the validity time of information 507 advertised in TC messages: 509 T_HOLD_TIME - is used to define the minimum value in the 510 VALIDITY_TIME TLV included in all TC messages sent by this node. 511 If a single value of parameter TC_HOP_LIMIT (see Section 5.6) is 512 used then this will be the only value in that TLV. 514 A_HOLD_TIME - is the period during which TC messages are sent after 515 they no longer have any advertised information to report, but are 516 sent in order to accelerate outdated information removal by other 517 nodes. 519 The following constraints apply to these parameters: 521 o T_HOLD_TIME > 0 523 o A_HOLD_TIME >= 0 525 o T_HOLD_TIME >= TC_INTERVAL 527 o If TC messages can be lost then both T_HOLD_TIME and A_HOLD_TIME 528 SHOULD be significantly greater than TC_INTERVAL; a value >= 3* 529 TC_INTERVAL is RECOMMENDED. 531 o T_HOLD_TIME MUST be representable as described in [2]. 533 5.4. Received Message Validity Times 535 The following parameters manage the validity time of recorded 536 received message information: 538 RX_HOLD_TIME - is an interface parameter, and is the period after 539 receipt of a message by the appropriate OLSRv2 interface of this 540 node for which that information is recorded, in order that the 541 message is recognized as having been previously received on this 542 OLSRv2 interface. 544 P_HOLD_TIME - is the period after receipt of a message which is 545 processed by this node for which that information is recorded, in 546 order that the message is not processed again if received again. 548 F_HOLD_TIME - is the period after receipt of a message which is 549 forwarded by this node for which that information is recorded, in 550 order that the message is not forwarded again if received again. 552 The following constraints apply to these parameters: 554 o RX_HOLD_TIME > 0 556 o P_HOLD_TIME > 0 558 o F_HOLD_TIME > 0 560 o All of these parameters SHOULD be greater than the maximum 561 difference in time that a message may take to traverse the MANET, 562 taking into account any message forwarding jitter as well as 563 propagation, queuing, and processing delays. 565 5.5. Jitter 567 If jitter, as defined in [3], is used then these parameters are as 568 follows: 570 TP_MAXJITTER - represents the value of MAXJITTER used in [3] for 571 periodically generated TC messages sent by this node. 573 TT_MAXJITTER - represents the value of MAXJITTER used in [3] for 574 externally triggered TC messages sent by this node. 576 F_MAXJITTER - represents the default value of MAXJITTER used in [3] 577 for messages forwarded by this node. However before using 578 F_MAXJITTER a node MAY attempt to deduce a more appropriate value 579 of MAXJITTER, for example based on any INTERVAL_TIME or 580 VALIDITY_TIME TLVs contained in the message to be forwarded. 582 For constraints on these parameters see [3]. 584 5.6. Hop Limit Parameter 586 The parameter TC_HOP_LIMIT is the hop limit set in each TC message. 587 TC_HOP_LIMIT MAY be a single fixed value, or MAY be different in TC 588 messages sent by the same node. However each other node SHOULD see a 589 regular pattern of TC messages, in order that meaningful values of 590 INTERVAL_TIME and VALIDITY_TIME TLVs at each hop count distance can 591 be included as defined in [2]. Thus the pattern of TC_HOP_LIMIT 592 SHOULD be defined to have this property. For example the repeating 593 pattern (255 4 4) satisfies this property (having period TC_INTERVAL 594 at hop counts up to 4, inclusive, and 3 x TC_INTERVAL at hop counts 595 greater than 4), but the repeating pattern (255 255 4 4) does not 596 satisfy this property. 598 The following constraints apply to this parameter: 600 o The maximum value of TC_HOP_LIMIT >= the network diameter in hops, 601 a value of 255 is RECOMMENDED. 603 o All values of TC_HOP_LIMIT >= 2. 605 5.7. Willingness 607 Each node has a WILLINGNESS parameter, which MUST be in the range 608 WILL_NEVER to WILL_ALWAYS, inclusive, and represents its willingness 609 to be an MPR, and hence its willingness to forward messages and be an 610 intermediate node on routes. If a node has WILLINGNESS == WILL_NEVER 611 it does not perform these tasks. A MANET using OLSRv2 with too many 612 nodes with WILLINGNESS == WILL_NEVER will not function; it MUST be 613 ensured, by administrative or other means, that this does not happen. 615 Nodes MAY have different WILLINGNESS values; however the three 616 constants WILL_NEVER, WILL_DEFAULT and WILL_ALWAYS MUST have the 617 values defined in Section 5.7. (Use of WILLINGNESS == WILL_DEFAULT 618 allows a node to avoid including a WILLINGNESS TLV in its TC 619 messages, use of WILLINGNESS == WILL_ALWAYS means that a node will 620 always be selected as an MPR by all symmetric 1-hop neighbors.) 622 The following constraints apply to this parameter: 624 o WILLINGNESS >=; WILL_NEVER 626 o WILLINGNESS <=; WILL_ALWAYS 628 5.8. Parameter Change Constraints 630 This section presents guidelines, applicable if protocol parameters 631 are changed dynamically. 633 TC_INTERVAL 635 * If the TC_INTERVAL for a node increases, then the next TC 636 message generated by this node MUST be generated according to 637 the previous, shorter, TC_INTERVAL. Additional subsequent TC 638 messages MAY be generated according to the previous, shorter, 639 TC_INTERVAL. 641 * If the TC_INTERVAL for a node decreases, then the following TC 642 messages from this node MUST be generated according to the 643 current, shorter, TC_INTERVAL. 645 RX_HOLD_TIME 647 * If RX_HOLD_TIME for an OLSRv2 interface changes, then RX_time 648 for all Received Tuples for that OLSRv2 interface MAY be 649 changed. 651 P_HOLD_TIME 653 * If P_HOLD_TIME changes, then P_time for all Processed Tuples 654 MAY be changed. 656 F_HOLD_TIME 658 * If F_HOLD_TIME changes, then F_time for all Forwarded Tuples 659 MAY be changed. 661 TP_MAXJITTER 663 * If TP_MAXJITTER changes, then the periodic TC message schedule 664 on this node MAY be changed immediately. 666 TT_MAXJITTER 668 * If TT_MAXJITTER changes, then externally triggered TC messages 669 on this node MAY be rescheduled. 671 F_MAXJITTER 673 * If F_MAXJITTER changes, then TC messages waiting to be 674 forwarded with a delay based on this parameter MAY be 675 rescheduled. 677 TC_HOP_LIMIT 679 * If TC_HOP_LIMIT changes, and the node uses multiple values 680 after the change, then message intervals and validity times 681 included in TC messages MUST be respected. The simplest way to 682 do this is to start any new repeating pattern of TC_HOP_LIMIT 683 values with its largest value. 685 6. Information Bases 687 Each node maintains the Information Bases described in the following 688 sections. These are used for describing the protocol in this 689 document. An implementation of this protocol MAY maintain this 690 information in the indicated form, or in any other organization which 691 offers access to this information. Regardless of how information is 692 organised, from the time at which a tuple is indicated to be expired, 693 the information contained herein MUST be ignored in any further 694 processing. 696 The purpose of OLSRv2 is to determine the Routing Set, which may be 697 used to update IP's Routing Table, providing "next hop" routing 698 information for IP datagrams. OLSRv2 maintains the following 699 Information Bases: 701 Local Information Base - as defined in [4], extended by the addition 702 of a Local Attached Network Set, defined in Section 6.1.2. 704 Interface Information Bases - as defined in [4], one Interface 705 Information Base for each OLSRv2 interface. 707 Node Information Base - as defined in [4], extended by the addition 708 of three elements to each Neighbor Tuple, as defined in 709 Section 6.2. 711 Topology Information Base - this information base is specific to 712 OLSRv2, and is defined in Section 6.3. 714 Processing and Forwarding Information Base - this information base 715 is specific to OLSRv2, and is defined in Section 6.4. 717 All addresses, other than originator addresses, recorded in the 718 Information Bases MUST all be recorded with prefix lengths, in order 719 to allow comparison with addresses received in HELLO and TC messages. 721 The ordering of sequence numbers, when considering which is the 722 greater, is as defined in Section 18. 724 6.1. Local Information Base 726 The Local Information Base as defined in [4] is extended by the 727 addition of an Originator Set, defined in Section 6.1.1, and a Local 728 Attached Network Set, defined in Section 6.1.2. 730 6.1.1. Originator Set 732 A node's Originator Set records addresses that were recently 733 originator addresses. If a node's originator address is immutable 734 then this set is always empty and MAY be omitted. It consists of 735 Originator Tuples: 737 (O_orig_addr, O_time) 739 where: 741 O_orig_addr is a recently used originator address; 743 O_time specifies the time at which this Tuple expires and MUST be 744 removed. 746 6.1.2. Local Attached Network Set 748 A node's Local Attached Network Set records its local non-OLSRv2 749 interfaces that can act as gateways to other networks. The Local 750 Attached Network Set is not modified by this protocol. This protocol 751 MAY respond to changes to the Local Attached Network Set, which MUST 752 reflect corresponding changes in the node's status. It consists of 753 Local Attached Network Tuples: 755 (AL_net_addr, AL_dist) 757 where: 759 AL_net_addr is the network address of an attached network which can 760 be reached via this node. 762 AL_dist is the number of hops to the network with address 763 AL_net_addr from this node. 765 Attached networks local to this node SHOULD be treated as local non- 766 MANET interfaces, and added to the Local Interface Set, as specified 767 in [4], rather than being added to the Local Attached Network Set. 769 An attached network MAY also be attached to other nodes. 771 It is not the responsibility of OLSRv2 to maintain routes to networks 772 recorded in the Local Attached Network Set. 774 6.2. Node Information Base 776 Each Neighbor Tuple in the Neighbor Set has these additional 777 elements: 779 N_willingness is the node's willingness to be selected as an MPR, in 780 the range from WILL_NEVER to WILL_ALWAYS, both inclusive; 782 N_mpr is a boolean flag, describing if the neighbor is selected as 783 an MPR by this node; 785 N_mpr_selector is a boolean flag, describing if this neighbor has 786 selected this node as an MPR, i.e. is an MPR selector of this 787 node. 789 6.3. Topology Information Base 791 The Topology Information Base stores information required for the 792 generation and processing of TC messages, and received in TC 793 messages. The Advertised Neighbor Set contains interface addresses 794 of symmetric 1-hop neighbors which are to be reported in TC messages. 795 The Advertising Remote Node Set, the Topology Set and the Attached 796 Network Set record information received in TC messages. 798 Additionally, a Routing Set is maintained, derived from the 799 information recorded in the Neighborhood Information Base, Topology 800 Set, Attached Network Set and Advertising Remote Node Set. 802 6.3.1. Advertised Neighbor Set 804 A node's Advertised Neighbor Set contains interface addresses of 805 symmetric 1-hop neighbors which are to be advertised through TC 806 messages: 808 {A_neighbor_iface_addr} 810 In addition, an Advertised Neighbor Set Sequence Number (ANSN) is 811 maintained. Each time the Advertised Neighbor Set is updated, the 812 ANSN MUST be incremented. The ANSN MUST also be incremented if there 813 is a change to the set of Local Attached Network Tuples that are to 814 be advertised in the node's TC messages. 816 6.3.2. Advertising Remote Node Set 818 A node's Advertising Remote Node Set records information describing 819 each remote node in the network that transmits TC messages. It 820 consists of Advertising Remote Node Tuples: 822 (AR_orig_addr, AR_seq_number, AR_iface_addr_list, AR_time) 824 where: 826 AR_orig_addr is the originator address of a received TC message, 827 note that this does not include a prefix length; 829 AR_seq_number is the greatest ANSN in any TC message received which 830 originated from the node with originator address AR_orig_addr; 832 AR_iface_addr_list is the list of the interface addresses of the 833 node with originator address AR_orig_addr; 835 AR_time is the time at which this Tuple expires and MUST be removed. 837 6.3.3. Topology Set 839 A node's Topology Set records topology information about the network. 840 It consists of Topology Tuples: 842 (T_dest_iface_addr, T_orig_addr, T_seq_number, T_time) 844 where: 846 T_dest_iface_addr is an interface address of a destination node, 847 which may be reached in one hop from the node with originator 848 address T_orig_addr; 850 T_orig_addr is the originator address of a node which is the last 851 hop on a path towards the node with interface address 852 T_dest_iface_addr, note that this does not include a prefix 853 length; 855 T_seq_number is the greatest received ANSN associated with the 856 information contained in this Tuple; 858 T_time specifies the time at which this Tuple expires and MUST be 859 removed. 861 6.3.4. Attached Network Set 863 A node's Attached Network Set records information about networks 864 attached to other nodes. It consists of Attached Network Tuples: 866 (AN_net_addr, AN_orig_addr, AN_dist, AN_seq_number, AN_time) 868 where: 870 AN_net_addr is the network address of an attached network, which may 871 be reached via the node with originator address AN_orig_addr; 873 AN_orig_addr is the originator address of a node which can act as 874 gateway to the network with address AN_net_addr, note that this 875 does not include a prefix length; 877 AN_dist is the number of hops to the network with address 878 AN_net_addr from the node with originator address AN_orig_addr; 880 AN_seq_number is the greatest received ANSN associated with the 881 information contained in this Tuple; 883 AN_time specifies the time at which this Tuple expires and MUST be 884 removed. 886 6.3.5. Routing Set 888 A node's Routing Set records the selected path to each destination 889 for which a route is known. It consists of Routing Tuples: 891 (R_dest_addr, R_next_iface_addr, R_dist, R_local_iface_addr) 893 where: 895 R_dest_addr is the address of the destination, either the address of 896 an interface of a destination node, or the network address of an 897 attached network; 899 R_next_iface_addr is the OLSRv2 interface address of the "next hop" 900 on the selected path to the destination; 902 R_dist is the number of hops on the selected path to the 903 destination; 905 R_local_iface_addr is the address of the local OLSRv2 interface over 906 which a packet MUST be sent to reach the destination by the 907 selected path. 909 6.4. Processing and Forwarding Information Base 911 The Processing and Forwarding Information Base records information 912 required to ensure that a message is processed at most once and is 913 forwarded at most once per OLSRv2 interface of a node. 915 6.4.1. Received Set 917 A node has a Received Set per local OLSRv2 interface. Each Received 918 Set records the signatures of messages which have been received over 919 that OLSRv2 interface. Each consists of Received Tuples: 921 (RX_type, RX_orig_addr, RX_seq_number, RX_time) 923 where: 925 RX_type is the received message type, or zero if the received 926 message sequence number is not type-specific; 928 RX_orig_addr is the originator address of the received message; 930 RX_seq_number is the message sequence number of the received 931 message; 933 RX_time specifies the time at which this Tuple expires and MUST be 934 removed. 936 6.4.2. Processed Set 938 A node's Processed Set records signatures of messages which have been 939 processed by the node. It consists of Processed Tuples: 941 (P_type, P_orig_addr, P_seq_number, P_time) 943 where: 945 P_type is the processed message type, or zero if the processed 946 message sequence number is not type-specific; 948 P_orig_addr is the originator address of the processed message; 950 P_seq_number is the message sequence number of the processed 951 message; 953 P_time specifies the time at which this Tuple expires and MUST be 954 removed. 956 6.4.3. Forwarded Set 958 A node's Forwarded Set records signatures of messages which have been 959 processed by the node. It consists of Forwarded Tuples: 961 (F_type, F_orig_addr, F_seq_number, F_time) 963 where: 965 F_type is the forwarded message type, or zero if the forwarded 966 message sequence number is not type-specific; 968 F_orig_addr is the originator address of the forwarded message; 970 F_seq_number is the message sequence number of the forwarded 971 message; 973 F_time specifies the time at which this Tuple expires and MUST be 974 removed. 976 6.4.4. Relay Set 978 A node has a Relay Set per local OLSRv2 interface. Each Relay Set 979 records the OLSRv2 interface addresses of symmetric 1-hop neighbors, 980 such that the node is to forward messages received from those 981 neighbors' OLSRv2 interfaces, on that local OLSRv2 interface, if not 982 otherwise excluded from forwarding that message (e.g. by it having 983 been previously forwarded): 985 {RY_neighbor_iface_addr} 987 7. Packet Processing and Message Forwarding 989 On receiving a packet, as defined in [1], a node examines the packet 990 header and each of the message headers. If the message type is known 991 to the node, the message is processed locally according to the 992 specifications for that message type. The message is also 993 independently evaluated for forwarding. 995 7.1. Actions when Receiving an OLSRv2 Packet 997 On receiving a packet, a node MUST perform the following tasks: 999 1. The packet MAY be fully parsed on reception, or the packet and 1000 its messages MAY be parsed only as required. (It is possible to 1001 parse the packet header, or determine its absence, without 1002 parsing any messages. It is possible to divide the packet into 1003 messages without even fully parsing their headers. It is 1004 possible to determine whether a message is to be forwarded, and 1005 to forward it, without parsing its body. It is possible to 1006 determine whether a message is to be processed without parsing 1007 its body.) 1009 2. If parsing fails at any point the relevant entity (packet or 1010 message) MUST be silently discarded, other parts of the packet 1011 (up to the whole packet) MAY be silently discarded. 1013 3. Otherwise if the packet header is present and it contains a 1014 packet TLV block, then each TLV in it is processed according to 1015 its type if recognized, otherwise the TLV is ignored. 1017 4. Otherwise each message in the packet, if any, is treated 1018 according to Section 7.2. 1020 7.2. Actions when Receiving an OLSRv2 Message 1022 A node MUST perform the following tasks for each received message: 1024 1. If the message header cannot be correctly parsed according to the 1025 specification in [1], or if the node recognizes from the 1026 originator address of the message that the message is one which 1027 the receiving node itself originated (i.e. is the current 1028 originator address of the node, or is an O_orig_addr in an 1029 Originator Tuple) then the message MUST be silently discarded. 1031 2. Otherwise: 1033 1. If the message is a HELLO message, then the message is 1034 processed according to Section 10. 1036 2. Otherwise: 1038 1. If the message is of a known type, including being a TC 1039 message, then the message is considered for processing 1040 according to Section 7.3, AND; 1042 2. If for the message: 1044 - is present and > 1, AND; 1046 - is not present or < 255 1048 then the message is considered for forwarding according 1049 to Section 7.4. 1051 7.3. Message Considered for Processing 1053 If a message (the "current message") is considered for processing, 1054 then the following tasks MUST be performed: 1056 1. If a Processed Tuple exists with: 1058 * P_type == the message type of the current message, or 0 if the 1059 typedep bit in the message semantics octet in the message 1060 header of the current message is cleared ('0'), AND; 1062 * P_orig_addr == the originator address of the current message, 1063 AND; 1065 * P_seq_number == the message sequence number of the current 1066 message; 1068 then the current message MUST NOT be processed. 1070 2. Otherwise: 1072 1. Create a Processed Tuple with: 1074 + P_type = the message type of the current message, or 0 if 1075 the typedep bit in the message semantics octet in the 1076 message header of the current message is cleared ('0'); 1078 + P_orig_addr = the originator address of the current 1079 message; 1081 + P_seq_number = the sequence number of the current message; 1082 + P_time = current time + P_HOLD_TIME. 1084 2. Process the current message according to its type. 1086 7.4. Message Considered for Forwarding 1088 If a message is considered for forwarding, and it is either of a 1089 message type defined in this document (i.e. is a TC message) or of an 1090 unknown message type, then it MUST use the following algorithm. A 1091 message of a message type not defined in this document MAY, in an 1092 extension to this protocol, specify the use of this, or another 1093 algorithm. (Such an other algorithm MAY use the Received Set for the 1094 receiving interface, it SHOULD use the Forwarded Set similarly to the 1095 following algorithm.) 1097 If a message (the "current message") is considered for forwarding 1098 according to this algorithm, the following tasks MUST be performed: 1100 1. If the sending interface address (the source address of the IP 1101 datagram containing the current message) does not match (taking 1102 into account any address prefix of) an OLSRv2 interface address 1103 in an L_neighbor_iface_addr_list of a Link Tuple, with L_status 1104 == SYMMETRIC, in the Link Set for the OLSRv2 interface on which 1105 the current message was received (the "receiving interface") then 1106 the current message MUST be silently discarded. 1108 2. Otherwise: 1110 1. If a Received Tuple exists in the Received Set for the 1111 receiving interface, with: 1113 + RX_type == the message type of the current message, or 0 1114 if the typedep bit in the message semantics octet in the 1115 message header of the current message is cleared ('0'), 1116 AND; 1118 + RX_orig_addr == the originator address of the current 1119 message, AND; 1121 + RX_seq_number == the sequence number of the current 1122 message; 1124 then the current message MUST be silently discarded. 1126 2. Otherwise: 1128 1. Create a Received Tuple in the Received Set for the 1129 receiving interface with: 1131 - RX_type = the message type of the current message, or 1132 0 if the typedep bit in the message semantics octet in 1133 the message header of the current message is cleared 1134 ('0'); 1136 - RX_orig_addr = originator address of the current 1137 message; 1139 - RX_seq_number = sequence number of the current 1140 message; 1142 - RX_time = current time + RX_HOLD_TIME. 1144 2. If a Forwarded Tuple exists with: 1146 - F_type == the message type of the current message, or 1147 0 if the typedep bit in the message semantics octet in 1148 the message header of the current message is cleared 1149 ('0'); 1151 - F_orig_addr == the originator address of the current 1152 message, AND; 1154 - F_seq_number == the sequence number of the current 1155 message. 1157 then the current message MUST be silently discarded. 1159 3. Otherwise if the sending interface address matches 1160 (taking account of any address prefix of) an 1161 RY_neighbor_iface_addr in the Relay Set for the receiving 1162 interface, then: 1164 1. Create a Forwarded Tuple with: 1166 o F_type = the message type of the current message, 1167 or 0 if the typedep bit in the message semantics 1168 octet in the message header of the current message 1169 is cleared ('0'); 1171 o F_orig_addr = originator address of the current 1172 message; 1174 o F_seq_number = sequence number of the current 1175 message; 1177 o F_time = current time + F_HOLD_TIME. 1179 2. The message header of the current message is modified 1180 by: 1182 o decrement in the message header by 1; 1184 o increment in the message header by 1. 1186 3. For each OLSRv2 interface of the node, include the 1187 message in a packet to be transmitted on that OLSRv2 1188 interface, as described in Section 8. This packet 1189 may contain other forwarded messages and/or messages 1190 generated by this node. Forwarded messages may be 1191 jittered as described in [3]. The value of MAXJITTER 1192 used in jittering a forwarded message MAY be based on 1193 information in that message (in particular any 1194 INTERVAL_TIME or VALIDITY_TIME TLVs in that message) 1195 or otherwise SHOULD be with maximum delay of 1196 F_MAXJITTER. A node MAY reduce the jitter applied to 1197 a message in order to more efficiently combine 1198 messages in packets. 1200 8. Packets and Messages 1202 Nodes using OLSRv2 exchange information through messages. One or 1203 more messages sent by a node at the same time SHOULD be combined into 1204 a single packet. These messages may have originated at the sending 1205 node, or have originated at another node and are forwarded by the 1206 sending node. Messages with different originating nodes MAY be 1207 combined in the same packet. Messages from other protocols defined 1208 using [1] MAY be combined in the same packet. 1210 The packet and message format used by OLSRv2 is defined in [1], 1211 where: 1213 o OLSRv2 packets MAY include packet TLVs, however OLSRv2 itself does 1214 not specify any packet TLVs. 1216 o All references in this specification to TLVs that do not indicate 1217 a type extension, assume Type Extension == 0. TLVs in processed 1218 messages with a non-zero type extension, or with a type extension 1219 which is not specifically indicated, as appropriate, are ignored. 1221 Other options defined in [1] may be freely used, in particular any 1222 other values of , , or 1223 consistent with their specifications. 1225 The remainder of this section defines, within the framework of [1], 1226 message types and TLVs specific to OLSRv2. 1228 8.1. HELLO Messages 1230 A HELLO message in OLSRv2 is generated as specified in [4]. 1231 Additionally, an OLSRv2 node: 1233 o MUST include TLV(s) with Type == MPR associated with all OLSRv2 1234 interface addresses included in the HELLO message with a TLV with 1235 Type == LINK_STATUS and Value == SYMMETRIC if that address is also 1236 included in Neighbor Tuple with N_mpr == true. (If there is more 1237 than one copy of such an address in the HELLO message, then this 1238 applies to the specific copy of the address with which the 1239 LINK_STATUS TLV is associated.) 1241 o MUST NOT include any TLVs with Type == MPR associated with any 1242 other addresses. 1244 o MAY include a message TLV with Type == WILLINGNESS, indicating the 1245 node's willingness to be selected as an MPR. 1247 8.1.1. HELLO Message TLVs 1249 In a HELLO message, a node MAY include a WILLINGNESS message TLV as 1250 specified in Table 1. A node MUST NOT include more than one 1251 WILLINGNESS message TLV. 1253 +-------------+--------+--------------------------------------------+ 1254 | Name | Value | Value | 1255 | | Length | | 1256 +-------------+--------+--------------------------------------------+ 1257 | WILLINGNESS | 8 bits | The node's willingness to be selected as | 1258 | | | MPR; unused bits (based on the maximum | 1259 | | | willingness value WILL_ALWAYS) are | 1260 | | | RESERVED and SHOULD be set to zero. | 1261 +-------------+--------+--------------------------------------------+ 1263 Table 1 1265 A node's willingness to be selected as MPR ranges from WILL_NEVER 1266 (indicating that a node MUST NOT be selected as MPR by any node) to 1267 WILL_ALWAYS (indicating that a node MUST always be selected as MPR). 1269 If a node does not advertise a Willingness TLV in HELLO messages, 1270 then the node MUST be assumed to have a willingness of WILL_DEFAULT. 1272 8.1.2. HELLO Message Address Block TLVs 1274 In a HELLO message, a node MAY include MPR address block TLV(s) as 1275 specified in Table 2. 1277 +------+--------------+-------+ 1278 | Name | Value Length | Value | 1279 +------+--------------+-------+ 1280 | MPR | 0 bits | None. | 1281 +------+--------------+-------+ 1283 Table 2 1285 8.2. TC Messages 1287 A TC message MUST contain: 1289 o , and elements in its 1290 message header, as specified in [1]. 1292 o A element in its message header if the message 1293 contsins either a VALIDITY_TIME or an INTERVAL_TIME TLV indicating 1294 more than one time value according to distance. 1296 o A single message TLV with Type == CONT_SEQ_NUM, and Type Extension 1297 == COMPLETE or Type Extension == INCOMPLETE, as specified in 1298 Section 8.2.1. 1300 o A message TLV with Type == VALIDITY_TIME, as specified in [2]. 1301 The options included in [2] for representing zero and infinite 1302 times MUST NOT be used. 1304 o All of the node's interface addresses. These MUST be included in 1305 the message's address blocks, unless: 1307 * the node has a single interface, with a single interface 1308 address with maximum prefix length, and 1310 * that address is the node's originator address. 1312 In this exceptional case, the address will be included as the 1313 message's originator address. 1315 o TLV(s) with Type == LOCAL_IF and Value == UNSPEC_IF associated 1316 with all of the node's interface addresses. 1318 o A complete TC message MUST include all addresses in the Advertised 1319 Address Set and selected addresses in the Local Attached Network 1320 Set, the latter (only) with associated GATEWAY address block 1321 TLV(s), as specified in Section 8.2.2. 1323 A TC message SHOULD have the mistypedep bit of , as 1324 defined in [1] cleared ('0'). 1326 A TC message MAY contain: 1328 o A message TLV with Type == INTERVAL_TIME, as specified in [2]. 1329 The options included in [2] for representing zero and infinite 1330 times MUST NOT be used. 1332 8.2.1. TC Message TLVs 1334 In a TC message, a node MUST include a single CONT_SEQ_NUM message 1335 TLV, as specified in Table 3, and with Type Extension == COMPLETE or 1336 Type Extension == INCOMPLETE. 1338 +--------------+------------+---------------------------------------+ 1339 | Name | Value | Value | 1340 | | Length | | 1341 +--------------+------------+---------------------------------------+ 1342 | CONT_SEQ_NUM | 8 bits | The ANSN contained in the Advertised | 1343 | | | Neighbor Set. | 1344 +--------------+------------+---------------------------------------+ 1346 Table 3 1348 8.2.2. TC Message Address Block TLVs 1350 In a TC message, a node MAY include GATEWAY address block TLV(s) as 1351 specified in Table 4. 1353 +---------+--------------+-------------------------------------+ 1354 | Name | Value Length | Value | 1355 +---------+--------------+-------------------------------------+ 1356 | GATEWAY | 8 bits | Number of hops to attached network. | 1357 +---------+--------------+-------------------------------------+ 1359 Table 4 1361 9. HELLO Message Generation 1363 An OLSRv2 HELLO message is composed as defined in [4], with the 1364 following additions: 1366 o A message TLV with Type == WILLINGNESS and Value == the node's 1367 willingness to act as an MPR, MAY be included. 1369 o For each address which is included in the message with an 1370 associated TLV with Type == LINK_STATUS and Value == SYMMETRIC, 1371 and is of an MPR (i.e. the address is in the 1372 N_neighbor_iface_addr_list of a Neighbor Tuple with N_mpr == 1373 true), an address block TLV with Type == MPR MUST be included; 1374 this TLV MUST be associated with the same copy of the address as 1375 is the TLV with Type == LINK_STATUS. 1377 o For each address which is included in the message and is not 1378 associated with a TLV with Type == LINK_STATUS and Value == 1379 SYMMETRIC, or is not of an MPR (i.e. the address is not in the 1380 N_neighbor_iface_addr_list of a Neighbor Tuple with N_mpr == 1381 true), an address block TLV with Type == MPR MUST NOT be 1382 associated with this address. 1384 9.1. HELLO Message: Transmission 1386 HELLO messages are included in packets as specified in [1]. These 1387 packets may contain other messages, including TC messages. 1389 10. HELLO Message Processing 1391 Subsequent to the processing of HELLO messages, as specified in [4], 1392 the node MUST identify the Neighbor Tuple which was created or 1393 updated by the processing specified in [4] (the "current Neighbor 1394 Tuple") and update N_willingness as described in Section 10.1 and 1395 N_mpr_selector as described in Section 10.2. 1397 10.1. Updating Willingness 1399 N_willingness in the current Neighbor Tuple is updated as follows: 1401 1. if the HELLO message contains a message TLV with Type == 1402 WILLINGNESS then N_willingness is set to the value of that TLV; 1404 2. otherwise, N_willingness is set to WILL_DEFAULT. 1406 10.2. Updating MPR Selectors 1408 N_mpr_selector is updated as follows: 1410 1. If a node finds one of its local OLSRv2 interface addresses with 1411 an associated TLV with Type == MPR in the HELLO message 1412 (indicating that the originator node has selected the receiving 1413 node as an MPR), then N_mpr_selector in the current Neighbor 1414 Tuple is set true. 1416 2. Otherwise, if a node finds one of its own interface addresses 1417 with an associated TLV with Type == LINK_STATUS and Value == 1418 SYMMETRIC in the HELLO message, then N_mpr_selector in the 1419 current Neighbor Tuple is set false. 1421 10.3. Symmetric 1-Hop and 2-Hop Neighborhood Changes 1423 A node MUST also perform the following: 1425 1. If N_symmetric of a Neighbor Tuple changes from true to false, 1426 then N_mpr_selector of that Neighbor Tuple MUST be set false. 1428 2. The set of MPRs of a node MUST be recalculated if: 1430 * a Link Tuple is added with L_status == SYMMETRIC, OR; 1432 * a Link Tuple with L_status == SYMMETRIC is removed, OR; 1434 * a Link Tuple with L_status == SYMMETRIC changes to having 1435 L_status == HEARD or L_status == LOST, OR; 1437 * a Link Tuple with L_status == HEARD or L_status == LOST 1438 changes to having L_status == SYMMETRIC, OR; 1440 * a 2-Hop Tuple is added or removed, OR; 1442 * the N_willingness of a Neighbor Tuple with N_symmetric == true 1443 changes from WILL_NEVER to any other value, OR; 1445 * the N_willingness of a Neighbor Tuple with N_symmetric == true 1446 and N_mpr == true changes to WILL_NEVER from any other value, 1447 OR; 1449 * the N_willingness of a Neighbor Tuple with N_symmetric == true 1450 and N_mpr == false changes to WILL_ALWAYS from any other 1451 value. 1453 3. Otherwise the set of MPRs of a node MAY be recalculated if the 1454 N_willingness of a Neighbor Tuple with N_symmetric == true 1455 changes in any other way; it SHOULD be recalculated if N_mpr == 1456 false and this is an increase in N_willingness or if N_mpr == 1457 true and this is a decrease in N_willingness. 1459 If the set of MPRs of a node is recalculated, this MUST be as 1460 described in Section 14. Before that calculation the N_mpr of all 1461 Neighbor Tuples are set false, after that calculation the N_mpr of 1462 all Neighbor Tuples representing symmetric 1-hop neighbors which are 1463 chosen as MPRs, are set true. 1465 A node MAY recognize the previous set of MPRs in the calculation of a 1466 new set of MPRs in order to minimise unnecessary changes to this set. 1468 An additional HELLO message MAY be sent when the node's set of MPRs 1469 changes, in addition to the cases specified in [4], and subject to 1470 the same constraints. 1472 11. TC Message Generation 1474 A node with one or more OLSRv2 interfaces, and with a non-empty 1475 Advertised Neighbor Set or a non-empty Local Attached Network Set 1476 MUST generate TC messages. A node with an empty Advertised Neighbor 1477 Set and and empty Local Attached Network Set SHOULD also generate 1478 "empty" TC messages for a period A_HOLD_TIME after it last generated 1479 a non-empty TC message. TC messages (non-empty and empty) are 1480 generated according to the following: 1482 1. The message hop count, if included, MUST be set to zero. 1484 2. The message hop limit MUST be set to a value greater than 1. A 1485 node MAY: 1487 * use the same hop limit TC_HOP_LIMIT in all TC messages, this 1488 MUST be at least equal to the network diameter in hops; OR 1490 * use different values of the hop limit TC_HOP_LIMIT in TC 1491 messages, this MUST regularly include messages with hop limit 1492 as defined above, other, lower, hop limits SHOULD use a 1493 regular pattern with a regular message interval at any given 1494 number of hops distance. 1496 3. The message MUST contain a message TLV with Type == CONT_SEQ_NUM 1497 and Value == ANSN from the Advertised Neighbor Set. If the TC 1498 message is complete then this message TLV MUST have Type 1499 Extension == COMPLETE, otherwise it MUST have Type Extension == 1500 INCOMPLETE. 1502 4. The message MUST contain a message TLV with Type == 1503 VALIDITY_TIME, as specified in [2]. If all TC messages are sent 1504 with the same hop limit then this TLV MUST have Value == 1505 T_HOLD_TIME. If TC messages are sent with different hop limits 1506 (more than one value of TC_HOP_LIMIT) then this TLV MUST specify 1507 times which vary with the number of hops distance appropriate to 1508 the chosen pattern of TC message hop limits, as specified in [2], 1509 these times SHOULD be appropriate multiples of T_HOLD_TIME. 1511 5. The message MAY contain a message TLV with Type == INTERVAL_TIME, 1512 as specified in [2]. If all TC messages are sent with the same 1513 hop limit then this TLV MUST have Value == TC_INTERVAL. If TC 1514 messages are sent with different hop limits, then this TLV MUST 1515 specify times which vary with the number of hops distance 1516 appropriate to the chosen pattern of TC message hop limits, as 1517 specified in [2], these times SHOULD be appropriate multiples of 1518 TC_INTERVAL. 1520 6. Unless the node has a single interface, with a single interface 1521 address with maximum prefix length, and that address is the 1522 node's originator address, the message MUST contain all of the 1523 node's interface addresses (i.e. all addresses in an 1524 I_local_iface_addr_list) in its address blocks. 1526 7. All addresses of the node's interfaces included in an address 1527 block MUST be associated with a TLV with Type == LOCAL_IF and 1528 Value == UNSPEC_IF. 1530 8. The message MUST include in its address blocks: 1532 1. A_neighbor_iface_addr from each Advertised Neighbor Tuple; 1534 2. AL_net_addr from each Local Attached Neighbor Tuple, each 1535 associated with a TLV with Type == GATEWAY and Value == 1536 AL_dist. 1538 11.1. TC Message: Transmission 1540 Complete TC messages are generated and transmitted periodically on 1541 all OLSRv2 interfaces, with a default interval between two 1542 consecutive TC transmissions by the same node of TC_INTERVAL. 1544 TC messages MAY be generated in response to a change of contents, 1545 indicated by a change in ANSN. In this case a node MAY send a 1546 complete TC message, and if so MAY re-start its TC message schedule. 1547 Alternatively a node MAY send an incomplete TC message with only new 1548 content in its address blocks. Note that a node cannot report 1549 removal of advertised content using an incomplete TC message. 1551 When sending a TC message in response to a change of contents, a node 1552 must respect a minimum interval of TC_MIN_INTERVAL between generated 1553 TC messages. Sending an incomplete TC message MUST NOT cause the 1554 interval between complete TC messages to be increased, and thus a 1555 node MUST NOT send an incomplete TC message if within TC_MIN_INTERVAL 1556 of the next scheduled complete TC message. 1558 The generation of TC messages, whether scheduled or triggered by a 1559 change of contents MAY be jittered as described in [3]. The values 1560 of MAXJITTER used SHOULD be: 1562 o TP_MAXJITTER for periodic TC message generation; 1564 o TT_MAXJITTER for triggered TC message generation. 1566 TC messages are included in packets as specified in [1]. These 1567 packets MAY contain other messages, including HELLO messages and TC 1568 messages with different originator addresses. TC messages are 1569 forwarded according to the specification in Section 7.4. 1571 12. TC Message Processing 1573 When according to Section 7.3 a TC message is to be processed 1574 according to its type, this means that: 1576 o If any address associated with a TLV with Type == LOCAL_IF is one 1577 of the receiving node's current or recently used interface 1578 addresses (i.e. is in any I_local_iface_addr_list in the Local 1579 Interface Set or is equal to any IR_local_iface_addr in the 1580 Removed Interface Address Set), then the TC message MUST be 1581 discarded. 1583 o If the TC message does not contain exactly one message TLV with 1584 Type == CONT_SEQ_NUM and Type Extension == COMPLETE or Type 1585 Extension == INCOMPLETE, then the TC message MUST be discarded. 1587 o If the TC message contains a message TLV with Type == CONT_SEQ_NUM 1588 and Type Extension == COMPLETE, then processing according to 1589 Section 12.1 and then according to Section 12.2 is carried out. 1591 o If the TC message contains a message TLV with Type == CONT_SEQ_NUM 1592 and Type Extension == INCOMPLETE, then only processing according 1593 to Section 12.1 is carried out. 1595 12.1. Initial TC Message Processing 1597 For the purposes of this section: 1599 o "originator address" refers to the originator address in the TC 1600 message header. 1602 o "validity time" is calculated from the VALIDITY_TIME message TLV 1603 in the TC message according to the specification in [2]. All 1604 information in the TC message has the same validity time. 1606 o "ANSN" is defined as being the value of the message TLV with Type 1607 == CONT_SEQ_NUM. 1609 o "sending address list" refers to the list of addresses in all 1610 address blocks which have associated TLV with Type == LOCAL_IF and 1611 Value == UNSPEC_IF. If the sending address list is otherwise 1612 empty, then the message's originator address is added to the 1613 sending address list, with maximum prefix length. 1615 o Comparisons of sequence numbers are carried out as specified in 1616 Section 18. 1618 The TC message is processed as follows: 1620 1. The Advertising Remote Node Set is updated according to 1621 Section 12.1.1; if the TC message is indicated as discarded in 1622 that processing then the following steps are not carried out. 1624 2. The Topology Set is updated according to Section 12.1.2. 1626 3. The Attached Network Set is updated according to Section 12.1.3. 1628 12.1.1. Populating the Advertising Remote Node Set 1630 The node MUST update its Advertising Remote Node Set as follows: 1632 1. If there is an Advertising Remote Node Tuple with: 1634 * AR_orig_addr == originator address; AND 1636 * AR_seq_number > ANSN 1638 then the TC message MUST be discarded. 1640 2. Otherwise: 1642 1. If there is no Advertising Remote Node Tuple such that: 1644 + AR_orig_addr == originator address; 1646 then create an Advertising Remote Node Tuple with: 1648 + AR_orig_addr = originator address. 1650 2. This Advertising Remote Node Tuple (existing or new, the 1651 "current tuple") is then modified as follows: 1653 + AR_seq_number = ANSN; 1655 + AR_time = current time + validity time. 1657 + AR_iface_addr_list = sending address list 1659 3. For each other Advertising Remote Node Tuple (with a 1660 different AR_orig_addr, the "other tuple") whose 1661 AR_iface_addr_list contains any address in the 1662 AR_iface_addr_list of the current tuple: 1664 1. remove all Topology Tuples with T_orig_addr == 1665 AR_orig_addr of the other tuple; 1667 2. remove all Attached Network Tuples with AN_orig_addr == 1668 AR_orig_addr of the other tuple; 1670 3. remove the other tuple. 1672 12.1.2. Populating the Topology Set 1674 The node MUST update its Topology Set as follows: 1676 1. For each address (henceforth advertised address) in an address 1677 block which does not have an associated TLV with Type == 1678 LOCAL_IF, or an associated TLV with Type == GATEWAY: 1680 1. If there is no Topology Tuple such that: 1682 + T_dest_iface_addr == advertised address; AND 1684 + T_orig_addr == originator address 1686 then create a new Topology Tuple with: 1688 + T_dest_iface_addr = advertised address; 1690 + T_orig_addr = originator address. 1692 2. This Topology Tuple (existing or new) is then modified as 1693 follows: 1695 + T_seq_number = ANSN; 1697 + T_time = current time + validity time. 1699 12.1.3. Populating the Attached Network Set 1701 The node MUST update its Attached Network Set as follows: 1703 1. For each address (henceforth network address) in an address block 1704 which does not have an associated TLV with Type == LOCAL_IF, and 1705 does have an associated TLV with Type == GATEWAY: 1707 1. If there is no Attached Network Tuple such that: 1709 + AN_net_addr == network address; AND 1711 + AN_orig_addr == originator address 1713 then create a new Attached Network Tuple with: 1715 + AN_net_addr = network address; 1717 + AN_orig_addr = originator address 1719 2. This Attached Network Tuple (existing or new) is then 1720 modified as follows: 1722 + AN_dist = the value of the associated GATEWAY TLV; 1724 + AN_seq_number = ANSN; 1726 + AN_time = current time + validity time. 1728 12.2. Completing TC Message Processing 1730 The TC message is processed as follows: 1732 1. The Topology Set is updated according to Section 12.2.1. 1734 2. The Attached Network Set is updated according to Section 12.2.2. 1736 12.2.1. Purging the Topology Set 1738 The Topology Set MUST be updated as follows: 1740 Any Topology Tuples with: 1742 o T_orig_addr == originator address; AND 1744 o T_seq_number < ANSN 1746 MUST be removed. 1748 12.2.2. Purging the Attached Network Set 1750 The Attached Network Set MUST be updated as follows: 1752 1. Any Attached Network Tuples with: 1754 * AN_orig_addr == originator address; AND 1756 * AN_seq_number < ANSN 1758 MUST be removed. 1760 13. Information Base Changes 1762 The Originator Set in the Local Information Base MUST be updated when 1763 the node changes originator address. If there is no Originator Tuple 1764 with: 1766 o O_orig_addr == old originator address 1768 then create an Originator Tuple with: 1770 o O_orig_addr = old originator address 1772 This Originator Tuple (existing or new) is then modified as follows: 1774 o O_time = current time + O_HOLD_TIME 1776 The Topology Information Base MUST be changed when an Advertising 1777 Remote Node Tuple expires (AR_time is reached). The following 1778 changes are required before the Advertising Remote Node Tuple is 1779 removed: 1781 1. All Topology Tuples with: 1783 * T_orig_addr == AR_orig_addr of the Advertising Remote Node 1784 Tuple 1786 are removed. 1788 2. All Attached Network Tuples with: 1790 * AN_orig_addr == AR_orig_addr of the Advertising Remote Node 1791 Tuple 1793 are removed. 1795 14. Selecting MPRs 1797 Each node MUST select, from among its symmetric 1-hop neighbors, a 1798 subset of nodes as MPRs. MPRs are used to flood control messages 1799 from a node into the network, while reducing the number of 1800 retransmissions that will occur in a region. Thus, the concept of 1801 MPR flooding is an optimization of a classical flooding mechanism. 1802 MPRs MAY also be used to reduce the shared topology information in 1803 the network. Consequently, while it is not essential that the set of 1804 MPRs is minimal, keeping the number of MPRs small ensures that the 1805 overhead of OLSRv2 is kept at a minimum. 1807 A node MUST select MPRs for each of its OLSRv2 interfaces, but then 1808 forms the union of those sets as its single set of MPRs. This union 1809 MUST include all symmetric 1-hop neighbors with willingness 1810 WILL_ALWAYS. Only this overall set of MPRs is relevant and recorded, 1811 the MPR relationship is one of nodes, not interfaces. Nodes MAY 1812 select their MPRs by any process which satisfies the conditions which 1813 follow. Nodes can freely interoperate whether they use the same or 1814 different MPR selection algorithms. 1816 For each OLSRv2 interface a node MUST select a set of MPRs which have 1817 the property that none of them have willingness WILL_NEVER, and that 1818 if the node successfully sends a message on that OLSRv2 interface, 1819 and that message is then successfully forwarded by all of the 1820 selected MPRs, that all symmetric strict 2-hop neighbors of the node 1821 by that OLSRv2 interface will receive that message on a symmetric 1822 link. 1824 Note that it is always possible to select a valid set of MPRs, the 1825 set of all symmetric 1-hop neighbors of a node which do not have 1826 willingness WILL_NEVER is a (maximal) valid set of MPRs. A node 1827 SHOULD NOT select a symmetric 1-hop neighbor with willingness not 1828 equal to WILL_ALWAYS as an MPR if there are no symmetric strict 2-hop 1829 neighbors with a symmetric link to that symmetric 1-hop neighbor. 1830 Thus a node with no symmetric 1-hop neighbors with willingness 1831 WILL_ALWAYS and no symmetric strict 2-hop neighbors SHOULD NOT select 1832 any MPRs. 1834 A node MAY select its MPRs for each OLSRv2 interface independently, 1835 or it MAY coordinate its MPR selections across its OLSRv2 interfaces, 1836 as long as the required condition is satisfied for each OLSRv2 1837 interface. Each node MAY select its MPRs independently from the MPR 1838 selection by other nodes, or it MAY, for example, give preference to 1839 nodes that either are, or are not, already selected as MPRs by other 1840 nodes. 1842 The set of MPRs for each OLSRv2 interface can be selected using 1843 information from the Link Set and 2-Hop Set of that OLSRv2 interface, 1844 and the Neighbor Set of the node (specifically the N_willingness 1845 elements). The selection of MPRs (overall, not per OLSRv2 interface) 1846 is recorded in the Neighbor Set of the node (using the N_mpr 1847 elements). A selected MPR MUST be in the node's symmetric 1-hop 1848 neighborhood (i.e. the corresponding N_symmetric == true) and MUST 1849 NOT have the corresponding N_willingness == WILL_NEVER. 1851 A node MUST recalculate its MPRs whenever the currently selected set 1852 of MPRs does not still satisfy the required conditions. It MAY 1853 recalculate its MPRs if the current set of MPRs is still valid, but 1854 could be more efficient. It is sufficient to recalculate a node's 1855 MPRs when there is a change to any of the node's Link Sets affecting 1856 the symmetry of any link (addition or removal of a Link Tuple with 1857 L_status == SYMMETRIC, or change of any L_status to or from 1858 SYMMETRIC), any change to any of the node's 2-Hop Sets, or a change 1859 of the N_willingness (to or from WILL_NEVER or to WILL_ALWAYS is 1860 sufficient) of any Neighbor Tuple with N_symmetric == true. 1862 An algorithm that creates a set of MPRs that satisfies the required 1863 conditions is given in Appendix B. 1865 15. Populating Derived Sets 1867 The Relay Sets and the Advertised Neighbor Set of a node are denoted 1868 derived sets, since updates to these sets are not directly a function 1869 of message exchanges, but rather are derived from updates to other 1870 sets, in particular to the MPR selector status of other nodes 1871 recorded in the Neighbor Set. 1873 15.1. Populating the Relay Set 1875 The Relay Set for an OLSRv2 interface contains the set of OLSRv2 1876 interface addresses of those symmetric 1-hop neighbors for which this 1877 OLSRv2 interface is to relay broadcast traffic. This set MUST 1878 contain only addresses of OLSRv2 interfaces with which this OLSRv2 1879 interface has a symmetric link. This set MUST include all such 1880 addresses of all such OLSRv2 interfaces of nodes which are MPR 1881 selectors of this node. The Relay Set for an OLSRv2 interface of 1882 this node is thus created by: 1884 1. For each Link Tuple in the Link Set for this OLSRv2 interface 1885 with L_status == SYMMETRIC, and the corresponding Neighbor Tuple 1886 with N_neighbor_iface_addr_list containing 1887 L_neighbor_iface_addr_list: 1889 1. All addresses from L_neighbor_iface_addr_list MUST be 1890 included in the Relay Set of this OLSRv2 interface if 1891 N_mpr_selector == true, and otherwise MAY be so included. 1893 15.2. Populating the Advertised Neighbor Set 1895 The Advertised Neighbor Set of a node contains all interface 1896 addresses of those symmetric 1-hop neighbors to which the node 1897 advertises a link in its TC messages. This set MUST include all 1898 addresses in all MPR selector of this node. The Advertised Neighbor 1899 Set for this node is thus created by: 1901 1. For each Neighbor Tuple with N_symmetric == true: 1903 1. All addresses from N_neighbor_iface_addr_list MUST be 1904 included in the Advertised Neighbor Set if N_mpr_selector == 1905 true, and otherwise MAY be so included. 1907 Whenever address(es) are added to or removed from the Advertised 1908 Neighbor Set, its ANSN MUST be incremented. 1910 16. Routing Set Calculation 1912 The Routing Set of a node is populated with Routing Tuples that 1913 represent paths from that node to all destinations in the network. 1914 These paths are calculated based on the Network Topology Graph, which 1915 is constructed from information in the Information Bases, obtained 1916 via HELLO and TC message exchange. 1918 16.1. Network Topology Graph 1920 The Network Topology Graph is formed from information taken from the 1921 node's Link Sets, Neighbor Set, Topology Set and Attached Network 1922 Set. The Network Topology Graph SHOULD also use information taken 1923 from the node's 2-Hop Sets. The Network Topology Graph forms that 1924 node's topological view of the network in form of a directed graph, 1925 containing the following arcs: 1927 o Local symmetric links - all arcs X -> Y such that: 1929 * X is an address in the I_local_iface_addr_list of a Local 1930 Interface Tuple of this node, AND; 1932 * Y is an address in the L_neighbor_iface_addr_list of a Link 1933 Tuple in the corresponding (to the OLSRv2 interface of that 1934 I_local_iface_addr_list) Link Set which has L_status == 1935 SYMMETRIC. 1937 o 2-hop symmetric links - all arcs Y -> Z such that: 1939 * Y is an address in the L_neighbor_iface_addr_list of a Link 1940 Tuple, in any of the node's Link Sets, which has L_status == 1941 SYMMETRIC, AND; 1943 * the Neighbor Tuple with Y in its N_neighbor_iface_addr_list has 1944 N_willingness not equal to WILL_NEVER, AND; 1946 * Z is the N2_2hop_iface_addr of a 2-Hop Tuple in the 2-Hop Set 1947 corresponding to the OLSRv2 interface of the chosen Link Set. 1949 o Advertised symmetric links - all arcs U -> V such that there 1950 exists a Topology Tuple and a corresponding Advertising Remote 1951 Node Tuple (i.e. with AR_orig_addr == T_orig_addr) with: 1953 * U is in the AR_iface_addr_list of the Advertising Remote Node 1954 Tuple, AND; 1956 * V is the T_dest_iface_addr of the Topology Tuple. 1958 o Symmetric 1-hop neighbor addresses - all arcs Y -> W such that: 1960 * Y is, and W is not, an address in the 1961 L_neighbor_iface_addr_list of a Link Tuple, in any of the 1962 node's Link Sets, which has L_status == SYMMETRIC, AND; 1964 * W and Y are included in the same N_neighbor_iface_addr_list 1965 (i.e. the one in the Neighbor Tuple whose 1966 N_neighbor_iface_addr_list contains the 1967 L_neighbor_iface_addr_list that includes Y). 1969 o Attached network addresses - all arcs U -> T such that there 1970 exists an Attached Network Tuple and a corresponding Advertising 1971 Remote Node Tuple (i.e. with AR_orig_addr == AN_orig_addr) with: 1973 * U is in the AR_iface_addr_list of the Advertising Remote Node 1974 Tuple, AND; 1976 * T is the AN_net_addr of the Attached Network Tuple. 1978 All links in the first three cases above have a hop count of one, the 1979 symmetric 1-hop neighbor addresses have a hop count of zero, and the 1980 attached network addresses have a hop count given by the appropriate 1981 value of AN_dist. 1983 16.2. Populating the Routing Set 1985 The Routing Set MUST contain the shortest paths for all destinations 1986 from all local OLSRv2 interfaces using the Network Topology Graph. 1987 This calculation MAY use any algorithm, including any means of 1988 choosing between paths of equal length. 1990 Using the notation of Section 16.1, each path will have as its first 1991 arc a local symmetric link X -> Y. There will be a path for each 1992 terminating Y, Z, V, W and T which can be connected to local OLSRv2 1993 interface address X using the indicated arcs. The corresponding 1994 Routing Tuple for this path will have: 1996 o R_dest_addr = the terminating Y, Z, V, W or T; 1998 o R_next_iface_addr = the first arc's Y; 2000 o R_dist = the total hop count of the path; 2002 o R_local_iface_addr = the first arc's X. 2004 An example algorithm for calculating the Routing Set of a node is 2005 given in Appendix C. 2007 16.3. Routing Set Updates 2009 The Routing Set MUST be updated when changes in the Neighborhood 2010 Information Base or the Topology Information Base indicate a change 2011 of the known symmetric links and/or attached networks in the MANET. 2012 It is sufficient to consider only changes which affect at least one 2013 of: 2015 o The Link Set of any OLSRv2 interface, and to consider only Link 2016 Tuples which have, or just had, L_status == SYMMETRIC (including 2017 removal of such Link Tuples). 2019 o The Neighbor Set of the node, and to consider only Neighbor Tuples 2020 that have, or just had, N_symmetric == true. 2022 o The 2-Hop Set of any OLSRv2 interface. 2024 o The Advertising Remote Node Set of the node. 2026 o The Topology Set of the node. 2028 o The Attached Network Set of the node. 2030 Updates to the Routing Set do not generate or trigger any messages to 2031 be transmitted. The state of the Routing Set SHOULD, however, be 2032 reflected in the IP routing table by adding and removing entries from 2033 the IP routing table as appropriate. 2035 17. Proposed Values for Parameters and Constants 2037 OLSRv2 uses all parameters and constants defined in [4] and 2038 additional parameters and constants defined in this document. All 2039 but one (RX_HOLD_TIME) of these additional parameters are node 2040 parameters as defined in [4]. These proposed values of the 2041 additional parameters are appropriate to the case where all 2042 parameters (including those defined in [4]) have a single value. 2043 Proposed values for parameters defined in [4] are given in that 2044 document. 2046 17.1. Local History Time Parameters 2048 o O_HOLD_TIME = 30 seconds 2050 17.2. Message Interval Parameters 2052 o TC_INTERVAL = 5 seconds 2054 o TC_MIN_INTERVAL = TC_INTERVAL/4 2056 17.3. Advertised Information Validity Time Parameters 2058 o T_HOLD_TIME = 3 x TC_INTERVAL 2060 o A_HOLD_TIME = T_HOLD_TIME 2062 17.4. Received Message Validity Time Parameters 2064 o RX_HOLD_TIME = 30 seconds 2066 o P_HOLD_TIME = 30 seconds 2068 o F_HOLD_TIME = 30 seconds 2070 17.5. Jitter Time Parameters 2072 o TP_MAXJITTER = HP_MAXJITTER 2074 o TT_MAXJITTER = HT_MAXJITTER 2076 o F_MAXJITTER = TT_MAXJITTER 2078 17.6. Hop Limit Parameter 2080 o TC_HOP_LIMIT = 255 2082 17.7. Willingness Parameter and Constants 2084 o WILLINGNESS = WILL_DEFAULT 2086 o WILL_NEVER = 0 2088 o WILL_DEFAULT = 3 2090 o WILL_ALWAYS = 7 2092 18. Sequence Numbers 2094 Sequence numbers are used in OLSRv2 with the purpose of discarding 2095 "old" information, i.e. messages received out of order. However with 2096 a limited number of bits for representing sequence numbers, wrap- 2097 around (that the sequence number is incremented from the maximum 2098 possible value to zero) will occur. To prevent this from interfering 2099 with the operation of OLSRv2, the following MUST be observed when 2100 determining the ordering of sequence numbers. 2102 The term MAXVALUE designates in the following one more than the 2103 largest possible value for a sequence number. For a 16 bit sequence 2104 number (as are those defined in this specification) MAXVALUE is 2105 65536. 2107 The sequence number S1 is said to be "greater than" the sequence 2108 number S2 if: 2110 o S1 > S2 AND S1 - S2 < MAXVALUE/2 OR 2112 o S2 > S1 AND S2 - S1 > MAXVALUE/2 2114 When sequence numbers S1 and S2 differ by MAXVALUE/2 their ordering 2115 cannot be determined. In this case, which should not occur, either 2116 ordering may be assumed. 2118 Thus when comparing two messages, it is possible - even in the 2119 presence of wrap-around - to determine which message contains the 2120 most recent information. 2122 19. Security Considerations 2124 Currently, OLSRv2 does not specify any special security measures. As 2125 a proactive routing protocol, OLSRv2 makes a target for various 2126 attacks. The various possible vulnerabilities are discussed in this 2127 section. 2129 19.1. Confidentiality 2131 Being a proactive protocol, OLSRv2 periodically MPR floods 2132 topological information to all nodes in the network. Hence, if used 2133 in an unprotected wireless network, the network topology is revealed 2134 to anyone who listens to OLSRv2 control messages. 2136 In situations where the confidentiality of the network topology is of 2137 importance, regular cryptographic techniques, such as exchange of 2138 OLSRv2 control traffic messages encrypted by PGP [8] or encrypted by 2139 some shared secret key, can be applied to ensure that control traffic 2140 can be read and interpreted by only those authorized to do so. 2142 19.2. Integrity 2144 In OLSRv2, each node is injecting topological information into the 2145 network through transmitting HELLO messages and, for some nodes, TC 2146 messages. If some nodes for some reason, malicious or malfunction, 2147 inject invalid control traffic, network integrity may be compromised. 2148 Therefore, message authentication is recommended. 2150 Different such situations may occur, for instance: 2152 1. a node generates TC messages, advertising links to non-neighbor 2153 nodes; 2155 2. a node generates TC messages, pretending to be another node; 2157 3. a node generates HELLO messages, advertising non-neighbor nodes; 2159 4. a node generates HELLO messages, pretending to be another node; 2161 5. a node forwards altered control messages; 2163 6. a node does not forward control messages; 2165 7. a node does not select multipoint relays correctly; 2167 8. a node forwards broadcast control messages unaltered, but does 2168 not forward unicast data traffic; 2170 9. a node "replays" previously recorded control traffic from another 2171 node. 2173 Authentication of the originator node for control messages (for 2174 situations 2, 4 and 5) and on the individual links announced in the 2175 control messages (for situations 1 and 3) may be used as a 2176 countermeasure. However to prevent nodes from repeating old (and 2177 correctly authenticated) information (situation 9) temporal 2178 information is required, allowing a node to positively identify such 2179 delayed messages. 2181 In general, digital signatures and other required security 2182 information may be transmitted as a separate OLSRv2 message type, or 2183 signatures and security information may be transmitted within the 2184 OLSRv2 HELLO and TC messages, using the TLV mechanism. Either option 2185 permits that "secured" and "unsecured" nodes can coexist in the same 2186 network, if desired, 2188 Specifically, the authenticity of entire OLSRv2 control packets can 2189 be established through employing IPsec authentication headers, 2190 whereas authenticity of individual links (situations 1 and 3) require 2191 additional security information to be distributed. 2193 An important consideration is that all control messages in OLSRv2 are 2194 transmitted either to all nodes in the neighborhood (HELLO messages) 2195 or broadcast to all nodes in the network (TC messages). 2197 For example, a control message in OLSRv2 is always a point-to- 2198 multipoint transmission. It is therefore important that the 2199 authentication mechanism employed permits that any receiving node can 2200 validate the authenticity of a message. As an analogy, given a block 2201 of text, signed by a PGP private key, then anyone with the 2202 corresponding public key can verify the authenticity of the text. 2204 19.3. Interaction with External Routing Domains 2206 OLSRv2 does, through the use of TC messages, provide a basic 2207 mechanism for injecting external routing information to the OLSRv2 2208 domain. Appendix A also specifies that routing information can be 2209 extracted from the topology table or the routing table of OLSRv2 and, 2210 potentially, injected into an external domain if the routing protocol 2211 governing that domain permits. 2213 Other than as described in Appendix A, when operating nodes 2214 connecting OLSRv2 to an external routing domain, care MUST be taken 2215 not to allow potentially insecure and untrustworthy information to be 2216 injected from the OLSRv2 domain to external routing domains. Care 2217 MUST be taken to validate the correctness of information prior to it 2218 being injected as to avoid polluting routing tables with invalid 2219 information. 2221 A recommended way of extending connectivity from an existing routing 2222 domain to an OLSRv2 routed MANET is to assign an IP prefix (under the 2223 authority of the nodes/gateways connecting the MANET with the exiting 2224 routing domain) exclusively to the OLSRv2 MANET area, and to 2225 configure the gateways statically to advertise routes to that IP 2226 sequence to nodes in the existing routing domain. 2228 20. IANA Considerations 2230 20.1. Message Types 2232 OLSRv2 defines one message type, which must be allocated from the 2233 "Assigned Message Types" repository of [1]. 2235 +------+-------+-------------------------------------+ 2236 | Name | Value | Description | 2237 +------+-------+-------------------------------------+ 2238 | TC | TBD1 | Topology Control (global signaling) | 2239 +------+-------+-------------------------------------+ 2241 Table 5 2243 20.2. TLV Types 2245 OLSRv2 defines two message TLV types, which must be allocated from 2246 the "Assigned message TLV Types" repository of [1]. 2248 +--------------+------+----------------+----------------------------+ 2249 | Name | Type | Type extension | Description | 2250 +--------------+------+----------------+----------------------------+ 2251 | WILLINGNESS | TBD2 | 0 | Specifies the originating | 2252 | | | | node's willingness to act | 2253 | | | | as a relay and to partake | 2254 | | | | in network formation | 2255 | | | | | 2256 | | | 1-255 | RESERVED | 2257 | | | | | 2258 | CONT_SEQ_NUM | TBD3 | 0 (COMPLETE) | Specifies a content | 2259 | | | | sequence number for this | 2260 | | | | complete message | 2261 | | | | | 2262 | | | 1 (INCOMPLETE) | Specifies a content | 2263 | | | | sequence number for this | 2264 | | | | incomplete message | 2265 | | | | | 2266 | | | 2-255 | RESERVED | 2267 +--------------+------+----------------+----------------------------+ 2269 Table 6 2271 Type extensions indicated as RESERVED may be allocated by standards 2272 action, as specified in [6]. 2274 OLSRv2 defines two Address Block TLV types, which must be allocated 2275 from the "Assigned address block TLV Types" repository of [1]. 2277 +---------+------+-----------+--------------------------------------+ 2278 | Name | Type | Type | Description | 2279 | | | extension | | 2280 +---------+------+-----------+--------------------------------------+ 2281 | MPR | TBD4 | 0 | Specifies that a given address is of | 2282 | | | | a node selected as an MPR | 2283 | | | | | 2284 | | | 1-255 | RESERVED | 2285 | | | | | 2286 | GATEWAY | TBD5 | 0 | Specifies that a given address is | 2287 | | | | reached via a gateway on the | 2288 | | | | originating node | 2289 | | | | | 2290 | | | 1-255 | RESERVED | 2291 +---------+------+-----------+--------------------------------------+ 2293 Table 7 2295 Type extensions indicated as RESERVED may be allocated by standards 2296 action, as specified in [6]. 2298 21. References 2300 21.1. Normative References 2302 [1] Clausen, T., Dean, J., Dearlove, C., and C. Adjih, "Generalized 2303 MANET Packet/Message Format", work in 2304 progress draft-ietf-manet-packetbb-11.txt, November 2007. 2306 [2] Clausen, T. and C. Dearlove, "Representing multi-value time in 2307 MANETs", Work In Progress draft-ietf-manet-timetlv-04.txt, 2308 November 2007. 2310 [3] Clausen, T., Dearlove, C., and B. Adamson, "Jitter 2311 considerations in MANETs", Work In 2312 Progress draft-ietf-manet-jitter-04.txt, December 2007. 2314 [4] Clausen, T., Dean, J., and C. Dearlove, "MANET Neighborhood 2315 Discovery Protocol (NHDP)", work in 2316 progress draft-ietf-manet-nhdp-05.txt, December 2007. 2318 [5] Bradner, S., "Key words for use in RFCs to Indicate Requirement 2319 Levels", RFC 2119, BCP 14, March 1997. 2321 [6] Narten, T. and H. Alvestrand, "Guidelines for Writing an IANA 2322 Considerations Section in RFCs", RFC 2434, BCP 26, 2323 October 1998. 2325 21.2. Informative References 2327 [7] Clausen, T. and P. Jacquet, "The Optimized Link State Routing 2328 Protocol", RFC 3626, October 2003. 2330 [8] Callas, J., Donnerhacke, L., Finney, H., and R. Thayer, 2331 "OpenPGP message format", RFC 4880, November 2007. 2333 [9] ETSI, "ETSI STC-RES10 Committee. Radio equipment and systems: 2334 HIPERLAN type 1, functional specifications ETS 300-652", 2335 June 1996. 2337 [10] Jacquet, P., Minet, P., Muhlethaler, P., and N. Rivierre, 2338 "Increasing reliability in cable free radio LANs: Low level 2339 forwarding in HIPERLAN.", 1996. 2341 [11] Qayyum, A., Viennot, L., and A. Laouiti, "Multipoint relaying: 2342 An efficient technique for flooding in mobile wireless 2343 networks.", 2001. 2345 [12] Macker, J. and S. Corson, "Mobile Ad hoc Networking (MANET): 2347 Routing Protocol Performance Issues and Evaluation 2348 Considerations", RFC 2501, January 1999. 2350 [13] Pei, G., Gerla, M., and T. Chen, "Fisheye state routing in 2351 mobile ad hoc networks", 2000. 2353 [14] Santivanez, C., Ramanathan, R., and I. Stavrakakis, "Making 2354 link-state routing scale for ad hoc networks", 2000. 2356 Appendix A. Node Configuration 2358 OLSRv2 does not make any assumption about node addresses, other than 2359 that each node is assumed to have at least one unique and routable IP 2360 address for each interface that it has which participates in the 2361 MANET. 2363 When applicable, a recommended way of connecting an OLSRv2 network to 2364 an existing IP routing domain is to assign an IP prefix (under the 2365 authority of the nodes/gateways connecting the MANET with the routing 2366 domain) exclusively to the OLSRv2 area, and to configure the gateways 2367 statically to advertise routes to that IP sequence to nodes in the 2368 existing routing domain. 2370 Appendix B. Example Algorithm for Calculating MPRs 2372 The following specifies an algorithm which MAY be used to select 2373 MPRs. MPRs are calculated per OLSRv2 interface, but then a single 2374 set of MPRs is formed from the union of the MPRs for all OLSRv2 2375 interfaces. A node's MPRs are recorded using the element N_mpr in 2376 Neighbor Tuples. 2378 If using this algorithm then the following steps MUST be executed in 2379 order for a node to select its MPRs: 2381 1. Set N_mpr = false in all Neighbor Tuples; 2383 2. For each Neighbor Tuple with N_symmetric == true and 2384 N_willingness == WILL_ALWAYS, set N_mpr = true; 2386 3. For each OLSRv2 interface of the node, use the algorithm in 2387 Appendix B.2. Note that this sets N_mpr = true for some Neighbor 2388 Tuples, these nodes are already selected as MPRs when using the 2389 algorithm for following OLSRv2 interfaces. 2391 4. OPTIONALLY, consider each selected MPR in turn, and if the set of 2392 selected MPRs without that node still satisfies the necessary 2393 conditions, for all OLSRv2 interfaces, then that node MAY be 2394 removed from the set of MPRs. This process MAY be repeated until 2395 no MPRs are removed. Nodes MAY be considered in order of 2396 increasing N_willingness. 2398 Symmetric 1-hop neighbor nodes with N_willingness == WILL_NEVER MUST 2399 NOT be selected as MPRs, and MUST be ignored in the following 2400 algorithm, as MUST be symmetric 2-hop neighbor nodes which are also 2401 symmetric 1-hop neighbor nodes (i.e. when considering 2-Hop Tuples, 2402 ignore any 2-Hop Tuples whose N2_2hop_iface_addr is in the 2403 N_neighbor_iface_addr_list of any Neighbor Tuple, or whose 2404 N2_neighbor_iface_addr_list is included in the 2405 N_neighbor_iface_addr_list of any Neighbor Tuple with N_willingness 2406 == WILL_NEVER). 2408 B.1. Terminology 2410 The following terminology will be used when selecting MPRs for the 2411 OLSRv2 interface I: 2413 N(I) - The set of symmetric 1-hop neighbors which have a symmetric 2414 link to I. 2416 N2(I) - The set of addresses of interfaces of a node with a 2417 symmetric link to a node in N(I) (i.e. the set of 2418 N2_2hop_iface_addr in 2-Hop Tuples in the 2-Hop Set for OLSRv2 2419 interface I). 2421 Connected to I via Y - An address A in N2(I) is connected to I via a 2422 node Y in N(I) if A is an address of an interface of a symmetric 2423 1-hop neighbor of Y (i.e. A is the N2_2hop_iface_addr in a 2-Hop 2424 Tuple in the 2-Hop Set for OLSRv2 interface I, and whose 2425 N2_neighbor_iface_addr_list is contained in the set of interface 2426 addresses of Y). 2428 D(Y, I) - For a node Y in N(I), the number of addresses in N2(I) 2429 which are connected to I via Y. 2431 R(Y, I): - For a node Y in N(I), the number of addresses in N2(I) 2432 which are connected to I via Y, but are not connected to I via any 2433 node which has already been selected as an MPR. 2435 B.2. MPR Selection Algorithm for each OLSRv2 Interface 2437 When selecting MPRs for the OLSRv2 interface I: 2439 1. For each address A in N2(I) for which there is only one node Y in 2440 N(I) such that A is connected to I via Y, select that node Y as 2441 an MPR (i.e. set N_mpr = true in the Neighbor Tuple corresponding 2442 to Y). 2444 2. While there exists any node Y in N(I) with R(Y, I) > 0: 2446 1. Select a node Y in N(I) with R(Y, I) > 0 in the following 2447 order of priority: 2449 + greatest N_willingness in the Neighbor Tuple corresponding 2450 to Y, THEN; 2452 + greatest R(Y, I), THEN; 2454 + greatest D(Y, I), THEN; 2456 + N_mpr_selector is equal to true, if possible, THEN; 2458 + any choice. 2460 2. Select Y as an MPR (i.e. set N_mpr = true in the Neighbor 2461 Tuple corresponding to Y). 2463 Appendix C. Example Algorithm for Calculating the Routing Set 2465 The following procedure is given as an example for calculating the 2466 Routing Set using a variation of Dijkstra's algorithm. First all 2467 Routing Tuples are removed, and then the procedures in the following 2468 sections are applied in turn. 2470 C.1. Add Local Symmetric Links 2472 1. For each Local Interface Tuple in the Local Interface Set: 2474 1. For each address A in I_local_iface_addr_list: 2476 1. For each Link Tuple in the Link Set for this local 2477 interface, with L_status == SYMMETRIC: 2479 1. For each address, B, in that Link Tuple's 2480 L_neighbor_iface_addr_list, add a new Routing Tuple 2481 with: 2483 o R_dest_addr = B; 2485 o R_next_iface_addr = B; 2487 o R_dist = 1; 2489 o R_local_iface_addr = A. 2491 2. For each Neighbor Tuple, for which there is an address B in 2492 N_neighbor_iface_addr_list, for which there is a Routing Tuple 2493 (the "previous Routing Tuple") with R_dest_addr == B: 2495 1. For each address C in N_neighbor_iface_addr_list for which 2496 there is no Routing Tuple with R_dest_addr == C, add a 2497 Routing Tuple with: 2499 + R_dest_addr = C; 2501 + R_next_iface_addr = B; 2503 + R_dist = 1; 2505 + R_local_iface_addr = R_local_iface_addr of the previous 2506 Routing Tuple. 2508 C.2. Add Remote Symmetric Links 2510 The following procedure, which adds Routing Tuples for destination 2511 nodes h+1 hops away, MUST be executed for each value of h, starting 2512 with h = 1 and incrementing by 1 for each iteration. The execution 2513 MUST stop if no new Routing Tuples are added in an iteration. 2515 1. For each Topology Tuple, if: 2517 * T_dest_iface_addr is not equal to R_dest_addr of any Routing 2518 Tuple, AND; 2520 * for the Advertising Remote Node Tuple with AR_orig_addr == 2521 T_orig_addr, there is an address in the AR_iface_addr_list 2522 which is equal to the R_dest_addr of a Routing Tuple (the 2523 "previous Routing Tuple") whose R_dist == h 2525 then add a new Routing Tuple, with: 2527 * R_dest_addr = T_dest_iface_addr; 2529 * R_next_iface_addr = R_next_iface_addr of the previous Routing 2530 Tuple; 2532 * R_dist = h+1; 2534 * R_local_iface_addr = R_local_iface_addr of the previous 2535 Routing Tuple. 2537 More than one Topology Tuple may be usable to select the next hop 2538 R_next_iface_addr for reaching the address R_dest_addr. Ties 2539 should be broken such that nodes with greater willingness are 2540 preferred, and between nodes of equal willingness, MPR selectors 2541 are preferred over non-MPR selectors. 2543 2. After the above iteration has completed, if h == 1, for each 2544 2-Hop Neighbor Tuple where: 2546 * N2_2hop_iface_addr is not equal to R_dest_addr of any Routing 2547 Tuple, AND; 2549 * The Neighbor Tuple whose N_neighbor_iface_addr_list contains 2550 N2_neighbor_iface_addr_list has N_willingness not equal to 2551 WILL_NEVER 2553 select a Routing Tuple (the "previous Routing Tuple") whose 2554 R_dest_addr is contained in N2_neighbor_iface_addr_list, and add 2555 a new Routing Tuple with: 2557 * R_dest_addr = N2_2hop_iface_addr; 2559 * R_next_iface_addr = R_next_iface_addr of the previous Routing 2560 Tuple; 2562 * R_dist = 2; 2564 * R_local_iface_addr = R_local_iface_addr of the previous 2565 Routing Tuple. 2567 More than one 2-Hop Neighbor Tuple may be usable to select the 2568 next hop R_next_iface_addr for reaching the address R_dest_addr. 2569 Ties should be broken such that nodes with greater willingness 2570 are preferred, and between nodes of equal willingness, MPR 2571 selectors are preferred over non-MPR selectors. 2573 C.3. Add Attached Networks 2575 1. For each Attached Network Tuple, if for the Advertising Remote 2576 Node Tuple with AR_orig_addr == AN_orig_addr, there is an address 2577 in the AR_iface_addr_list which is equal to the R_dest_addr of a 2578 Routing Tuple (the "previous Routing Tuple"), then: 2580 1. If there is no Routing Tuple with R_dest_addr == AN_net_addr, 2581 then add a new Routing Tuple with: 2583 + R_dest_addr = AN_net_addr; 2585 + R_next_iface_addr = R_next_iface_addr of the previous 2586 Routing Tuple; 2588 + R_dist = (R_dist of the previous Routing Tuple) + AN_dist; 2590 + R_local_iface_addr = R_local_iface_addr of the previous 2591 Routing Tuple. 2593 2. Otherwise if the Routing Tuple with R_dest_addr == 2594 AN_net_addr (the "current Routing Tuple") has R_dist > 2595 (R_dist of the previous Routing Tuple) + AN_dist, then modify 2596 the current Routing Tuple by: 2598 + R_next_iface_addr = R_next_iface_addr of the previous 2599 Routing Tuple; 2601 + R_dist = (R_dist of the previous Routing Tuple) + AN_dist; 2603 + R_local_iface_addr = R_local_iface_addr of the previous 2604 Routing Tuple. 2606 Appendix D. Example Message Layout 2608 An example TC message, using IPv4 (four octet) addresses, is as 2609 follows. The overall message length is 65 octets. 2611 The message has a message TLV block with content length 13 octets 2612 containing three TLVs. The first two TLVs are validity and interval 2613 times for the message. The third TLV is the content sequence number 2614 TLV used to carry the 2 octet ANSN, and (with default type extension 2615 zero, i.e. COMPLETE) indicating that the TC message is complete. 2616 Each TLV uses a TLV with semantics value 8, indicating no type 2617 extension or start and stop indexes are included. The first two TLVs 2618 have a value length of 1 octet, the last has a value length of 2 2619 octets. 2621 The message has two address blocks. The first address block contains 2622 6 addresses (with semantics octet 2, hence no tail section, head 2623 length 2 octets, and hence mid sections with length two octets). The 2624 following TLV block (content length 6 octets) contains a single 2625 LOCAL_IF TLV (semantics value 0) indicating that the first three 2626 addresses (indexes 0 to 2) are associated with the value (length 1 2627 octet) UNSPEC_IF, i.e. they are the originating node's local 2628 interface addresses. The remaining three addresses have no 2629 associated TLV, they are the interface addresses of advertised 2630 neighbors. 2632 The second address block contains 1 address, with semantics octet 12 2633 indicating that the tail section, length 2 octets, consists of zero 2634 valued octets (not included), and that there is a single prefix 2635 length, 16. The network address is thus Head.0.0/16. The following 2636 TLV block (content length 8 octets) includes one TLV that indicates 2637 that the originating node is a gateway to this network, at a given 2638 number of hops distance (value length 1 octet). The TLV semantics 2639 value of 8 indicates that no indexes are needed. 2641 0 1 2 3 2642 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 2643 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2644 | TC |0 0 0 0 0 0 0 0|0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 1| 2645 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2646 | Originator Address | 2647 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2648 | Hop Limit | Hop Count | Message Sequence Number | 2649 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2650 |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| 2651 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2652 |0 0 0 0 0 0 0 1| Value | INTERVAL_TIME |0 0 0 0 1 0 0 0| 2653 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2654 |0 0 0 0 0 0 0 1| Value | CONT_SEQ_NUM |0 0 0 0 1 0 0 0| 2655 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2656 |0 0 0 0 0 0 1 0| Value (ANSN) |0 0 0 0 0 1 1 0| 2657 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2658 |0 0 0 0 0 0 1 0|0 0 0 0 0 0 1 0| Head | 2659 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2660 | Mid | Mid | 2661 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2662 | Mid | Mid | 2663 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2664 | Mid | Mid | 2665 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2666 |0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 0| LOCAL_IF |0 0 0 0 0 0 0 0| 2667 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2668 |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 | 2669 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2670 |0 0 0 0 0 0 0 1|0 0 0 0 1 1 0 0|0 0 0 0 0 0 1 0| Head | 2671 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2672 | 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| 2673 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2674 |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| 2675 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 2676 | Number Hops | 2677 +-+-+-+-+-+-+-+-+ 2679 Appendix E. Constraints 2681 Any process which updates the Local Information Base, the 2682 Neighborhood Information Base or the Topology Information Base MUST 2683 ensure that all constraints specified in this appendix are 2684 maintained, as well as those specified in [4]. 2686 In each Originator Tuple: 2688 o O_orig_addr MUST NOT equal any other O_orig_addr. 2690 o O_orig_addr MUST NOT equal this node's originator address. 2692 In each Local Attached Network Tuple: 2694 o AL_net_addr MUST NOT equal any other AL_net_addr. 2696 o AL_net_addr MUST NOT be in the I_local_iface_addr_list of any 2697 Local Interface Tuple or be equal to the IR_local_iface_addr of 2698 any Removed Interface Address Tuple. 2700 o AL_dist MUST NOT be less than zero. 2702 In each Link Tuple: 2704 o L_neighbor_iface_addr_list MUST NOT contain the AL_net_addr of any 2705 Local Attached Network Tuple. 2707 o If L_status == SYMMETRIC and the Neighbor Tuple whose 2708 N_neighbor_iface_addr_list contains L_neighbor_iface_addr_list has 2709 N_mpr_selector == true, then, for each address in this 2710 L_neighbor_iface_addr_list, there MUST be an equal 2711 RY_neighbor_iface_addr in the Relay Set associated with the same 2712 OLSRv2 interface. 2714 In each Neighbor Tuple: 2716 o N_neighbor_iface_addr_list MUST NOT contain the AL_net_addr of any 2717 Local Attached Network Tuple. 2719 o If N_willingness MUST be in the range from WILL_NEVER to 2720 WILL_ALWAYS, inclusive. 2722 o If N_mpr == true, then N_symmetric MUST be true and N_willingness 2723 MUST NOT equal WILL_NEVER. 2725 o If N_symmetric == true and N_mpr == false, then N_willingness MUST 2726 NOT equal WILL_ALWAYS. 2728 o If N_mpr_selector == true, then N_symmetric MUST be true. 2730 o If N_mpr_selector == true, then, for each address in this 2731 N_neighbor_iface_addr_list, there MUST be an equal 2732 A_neighbor_iface_addr in the Advertised Neighbor Set. 2734 In each Lost Neighbor Tuple: 2736 o NL_neighbor_iface_addr MUST NOT equal the AL_net_addr of any Local 2737 Attached Network Tuple. 2739 In each 2-Hop Tuple: 2741 o N2_2hop_iface_addr MUST NOT equal the AL_net_addr of any Local 2742 Attached Network Tuple. 2744 In each Received Tuple: 2746 o RX_orig_addr MUST NOT equal this node's originator address or any 2747 O_orig_addr. 2749 o Each ordered triple (RX_type, RX_orig_addr, RX_seq_number) MUST 2750 NOT equal the corresponding triple in any other Received Tuple in 2751 the same Received Set. 2753 In each Processed Tuple: 2755 o P_orig_addr MUST NOT equal this node's originator address or any 2756 O_orig_addr. 2758 o Each ordered triple (P_type, P_orig_addr, P_seq_number) MUST NOT 2759 equal the corresponding triple in any other Processed Tuple. 2761 In each Forwarded Tuple: 2763 o F_orig_addr MUST NOT equal this node's originator address or any 2764 O_orig_addr. 2766 o Each ordered triple (F_type, F_orig_addr, F_seq_number) MUST NOT 2767 equal the corresponding triple in any other Forwarded Tuple. 2769 In each Relay Tuple: 2771 o RY_neighbor_iface_addr MUST NOT equal the RY_neighbor_iface_addr 2772 in any other Relay Tuple in the same Relay Set. 2774 o RY_neighbor_iface_addr MUST be in the L_neighbor_iface_addr_list 2775 of a Link Tuple with L_status == SYMMETRIC. 2777 In each Advertised Neighbor Tuple: 2779 o A_neighbor_iface_addr MUST NOT equal the A_neighbor_iface_addr of 2780 any other Advertised Neighbor Tuple. 2782 o A_neighbor_iface_addr MUST be in the N_neighbor_iface_addr_list of 2783 a Neighbor Tuple with N_symmetric == true. 2785 In each Advertising Remote Node Tuple: 2787 o AR_orig_addr MUST NOT equal this node's originator address or any 2788 O_orig_addr. 2790 o AR_orig_addr MUST NOT equal the AR_orig_addr in any other ANSN 2791 History Tuple. 2793 o AR_iface_addr_list MUST NOT be empty. 2795 o AR_iface_addr_list MUST NOT contain any duplicated addresses. 2797 o AR_iface_addr_list MUST NOT contain any address which is in the 2798 I_local_iface_addr_list of any Local Interface Tuple or be equal 2799 to the IR_local_iface_addr of any Removed Interface Address Tuple. 2801 o AR_iface_addr_list MUST NOT contain any address which is the 2802 AL_net_addr of any Local Attached Network Tuple. 2804 In each Topology Tuple: 2806 o T_dest_iface_addr MUST NOT be in the I_local_iface_addr_list of 2807 any Local Interface Tuple or be equal to the IR_local_iface_addr 2808 of any Removed Interface Address Tuple. 2810 o T_dest_iface_addr MUST NOT equal the AL_net_addr of any Local 2811 Attached Network Tuple. 2813 o There MUST be an Advertising Remote Node Tuple with AR_orig_addr 2814 == T_orig_addr. 2816 o T_dest_iface_addr MUST NOT be in the AR_iface_addr_list of the 2817 Advertising Remote Node Tuple with AR_orig_addr == T_orig_addr. 2819 o T_seq_number MUST NOT be greater than AR_seq_number of the 2820 Advertising Remote Node Tuple with AR_orig_addr == T_orig_addr. 2822 o The ordered pair (T_dest_iface_addr, T_orig_addr) MUST NOT equal 2823 the corresponding pair in any other Topology Tuple. 2825 In each Attached Network Tuple: 2827 o AN_net_addr MUST NOT be in the I_local_iface_addr_list of any 2828 Local Interface Tuple or be equal to the IR_local_iface_addr of 2829 any Removed Interface Address Tuple. 2831 o AN_net_addr MUST NOT equal the AL_net_addr of any Local Attached 2832 Network Tuple. 2834 o There MUST be an Advertising Remote Node Tuple with AR_orig_addr 2835 == AN_orig_addr. 2837 o AN_seq_number MUST NOT be greater than AR_seq_number of the 2838 Advertising Remote Node Tuple with AR_orig_addr == AN_orig_addr. 2840 o AN_dist MUST NOT be less than zero. 2842 o The ordered pair (AN_net_addr, AN_orig_addr) MUST NOT equal the 2843 corresponding pair in any other Attached Network Tuple. 2845 Appendix F. Flow and Congestion Control 2847 Due to its proactive nature, the OLSRv2 protocol has a natural 2848 control over the flow of its control traffic. Nodes transmit control 2849 messages at predetermined rates specified and bounded by message 2850 intervals. 2852 OLSRv2 employs [4] for local signaling, embedding MPR selection 2853 advertisement through a simple address block TLV, and node 2854 willingness advertisement (if any) as a single message TLV. OLSRv2 2855 local signaling, therefore, shares the characteristics and 2856 constraints of [4]. 2858 Furthermore, MPR flooding greatly reduces global signaling overhead 2859 from global link state declaration in two ways. First, the amount of 2860 link state information for a node to declare is reduced to only 2861 contain that node's MPR selectors. This reduces the size of a link 2862 state declaration as compared to declaring full link state 2863 information. In particular some nodes may not need to declare any 2864 such information. Second, using MPR flooding, the cost of declaring 2865 link state information throughout the network is greatly reduced, as 2866 compared to when using classic flooding, since only MPRs need to 2867 forward link state declaration messages. In dense networks, the 2868 reduction of control traffic can be of several orders of magnitude 2869 compared to routing protocols using classical flooding [11]. This 2870 feature naturally provides more bandwidth for useful data traffic and 2871 pushes further the frontier of congestion. 2873 Since the control traffic is continuous and periodic, it keeps the 2874 quality of the links used in routing more stable. However, using 2875 certain OLSRv2 options, some control messages (HELLO messages or TC 2876 messages) may be intentionally sent in advance of their deadline in 2877 order to increase the responsiveness of the protocol to topology 2878 changes. This may cause a small, temporary, and local increase of 2879 control traffic, however this is at all times bounded by the use of 2880 minimum message intervals. 2882 Appendix G. Contributors 2884 This specification is the result of the joint efforts of the 2885 following contributors -- listed alphabetically. 2887 o Cedric Adjih, INRIA, France, 2889 o Emmanuel Baccelli, INRIA , France, 2891 o Thomas Heide Clausen, LIX, France, 2893 o Justin Dean, NRL, USA, 2895 o Christopher Dearlove, BAE Systems, UK, 2896 2898 o Satoh Hiroki, Hitachi SDL, Japan, 2900 o Philippe Jacquet, INRIA, France, 2902 o Monden Kazuya, Hitachi SDL, Japan, 2904 o Kenichi Mase, Niigata University, Japan, 2906 o Ryuji Wakikawa, KEIO University, Japan, 2908 Appendix H. Acknowledgements 2910 The authors would like to acknowledge the team behind OLSRv1, 2911 specified in RFC3626, including Anis Laouiti (INT, Paris), Pascale 2912 Minet (INRIA, France), Laurent Viennot (INRIA, France), and Amir 2913 Qayyum (M.A. Jinnah University, Islamabad) for their contributions. 2915 The authors would like to gratefully acknowledge the following people 2916 for intense technical discussions, early reviews and comments on the 2917 specification and its components: Li Li (CRC), Louise Lamont (CRC), 2918 Joe Macker (NRL), Alan Cullen (BAE Systems), Khaldoun Al Agha (LRI), 2919 Richard Ogier (SRI), Song-Yean Cho (LIX), Shubhranshu Singh (Samsung 2920 AIT), Charles E. Perkins, and the entire IETF MANET working group. 2922 Authors' Addresses 2924 Thomas Heide Clausen 2925 LIX, Ecole Polytechnique, France 2927 Phone: +33 6 6058 9349 2928 Email: thomas@thomasclausen.org 2929 URI: http://www.ThomasClausen.org/ 2931 Christopher Dearlove 2932 BAE Systems Advanced Technology Centre 2934 Phone: +44 1245 242194 2935 Email: chris.dearlove@baesystems.com 2936 URI: http://www.baesystems.com/ 2938 Philippe Jacquet 2939 Project Hipercom, INRIA 2941 Phone: +33 1 3963 5263 2942 Email: philippe.jacquet@inria.fr 2944 The OLSRv2 Design Team 2945 MANET Working Group 2947 Full Copyright Statement 2949 Copyright (C) The IETF Trust (2008). 2951 This document is subject to the rights, licenses and restrictions 2952 contained in BCP 78, and except as set forth therein, the authors 2953 retain all their rights. 2955 This document and the information contained herein are provided on an 2956 "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS 2957 OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY, THE IETF TRUST AND 2958 THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS 2959 OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF 2960 THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED 2961 WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. 2963 Intellectual Property 2965 The IETF takes no position regarding the validity or scope of any 2966 Intellectual Property Rights or other rights that might be claimed to 2967 pertain to the implementation or use of the technology described in 2968 this document or the extent to which any license under such rights 2969 might or might not be available; nor does it represent that it has 2970 made any independent effort to identify any such rights. Information 2971 on the procedures with respect to rights in RFC documents can be 2972 found in BCP 78 and BCP 79. 2974 Copies of IPR disclosures made to the IETF Secretariat and any 2975 assurances of licenses to be made available, or the result of an 2976 attempt made to obtain a general license or permission for the use of 2977 such proprietary rights by implementers or users of this 2978 specification can be obtained from the IETF on-line IPR repository at 2979 http://www.ietf.org/ipr. 2981 The IETF invites any interested party to bring to its attention any 2982 copyrights, patents or patent applications, or other proprietary 2983 rights that may cover technology that may be required to implement 2984 this standard. Please address the information to the IETF at 2985 ietf-ipr@ietf.org. 2987 Acknowledgment 2989 Funding for the RFC Editor function is provided by the IETF 2990 Administrative Support Activity (IASA).