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You should update this to the boilerplate described in the IETF Trust License Policy document (see https://trustee.ietf.org/license-info), which is required now. -- Found old boilerplate from RFC 3978, Section 5.1 on line 16. -- Found old boilerplate from RFC 3978, Section 5.5 on line 1279. -- Found old boilerplate from RFC 3979, Section 5, paragraph 1 on line 1256. -- Found old boilerplate from RFC 3979, Section 5, paragraph 2 on line 1263. -- Found old boilerplate from RFC 3979, Section 5, paragraph 3 on line 1269. ** This document has an original RFC 3978 Section 5.4 Copyright Line, instead of the newer IETF Trust Copyright according to RFC 4748. ** This document has an original RFC 3978 Section 5.5 Disclaimer, instead of the newer disclaimer which includes the IETF Trust according to RFC 4748. Checking nits according to https://www.ietf.org/id-info/1id-guidelines.txt: ---------------------------------------------------------------------------- == No 'Intended status' indicated for this document; assuming Proposed Standard Checking nits according to https://www.ietf.org/id-info/checklist : ---------------------------------------------------------------------------- No issues found here. Miscellaneous warnings: ---------------------------------------------------------------------------- == The copyright year in the RFC 3978 Section 5.4 Copyright Line does not match the current year == The document seems to lack the recommended RFC 2119 boilerplate, even if it appears to use RFC 2119 keywords. (The document does seem to have the reference to RFC 2119 which the ID-Checklist requires). == Using lowercase 'not' together with uppercase 'MUST', 'SHALL', 'SHOULD', or 'RECOMMENDED' is not an accepted usage according to RFC 2119. Please use uppercase 'NOT' together with RFC 2119 keywords (if that is what you mean). Found 'MUST not' in this paragraph: If a node's OwnSeqNum is lost, it must take certain actions to avoid creating routing loops. To prevent this possibility after OwnSeqNum loss a node MUST wait for at least ROUTE_DELETE_PERIOD before fully participating in the DYMO routing protocol. If a DYMO control message is received during this waiting period, the node SHOULD process it normally but MUST not transmit or retransmit any DYMO messages. If a data packet is received for forwarding to another destination during this waiting period, the node MUST generate a RERR message indicating that this route is not available and reset its waiting period. RERR generation is described in Section 5.5.3. At the end of the waiting period a node sets its OwnSeqNum to one (1). == Using lowercase 'not' together with uppercase 'MUST', 'SHALL', 'SHOULD', or 'RECOMMENDED' is not an accepted usage according to RFC 2119. Please use uppercase 'NOT' together with RFC 2119 keywords (if that is what you mean). Found 'SHOULD not' in this paragraph: Discard If the Semantics.Discard-bit is set, this message SHOULD not be processed further and it should not be propagated. In the case of PktTLVs if the Semantics.Discard-bit is set, no messages from the packet should be processed or propagated. -- The document seems to lack a disclaimer for pre-RFC5378 work, but may have content which was first submitted before 10 November 2008. If you have contacted all the original authors and they are all willing to grant the BCP78 rights to the IETF Trust, then this is fine, and you can ignore this comment. If not, you may need to add the pre-RFC5378 disclaimer. (See the Legal Provisions document at https://trustee.ietf.org/license-info for more information.) -- The document date (June 20, 2006) is 6491 days in the past. Is this intentional? Checking references for intended status: Proposed Standard ---------------------------------------------------------------------------- (See RFCs 3967 and 4897 for information about using normative references to lower-maturity documents in RFCs) ** Obsolete normative reference: RFC 2434 (Obsoleted by RFC 5226) ** Obsolete normative reference: RFC 3513 (Obsoleted by RFC 4291) ** Downref: Normative reference to an Experimental RFC: RFC 3561 == Outdated reference: A later version (-15) exists of draft-ietf-manet-nhdp-00 == Outdated reference: A later version (-17) exists of draft-ietf-manet-packetbb-01 Summary: 6 errors (**), 0 flaws (~~), 7 warnings (==), 7 comments (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Mobile Ad hoc Networks Working I. Chakeres 3 Group Boeing 4 Internet-Draft C. Perkins 5 Expires: December 22, 2006 Nokia 6 June 20, 2006 8 Dynamic MANET On-demand (DYMO) Routing 9 draft-ietf-manet-dymo-05 11 Status of this Memo 13 By submitting this Internet-Draft, each author represents that any 14 applicable patent or other IPR claims of which he or she is aware 15 have been or will be disclosed, and any of which he or she becomes 16 aware will be disclosed, in accordance with Section 6 of BCP 79. 18 Internet-Drafts are working documents of the Internet Engineering 19 Task Force (IETF), its areas, and its working groups. Note that 20 other groups may also distribute working documents as Internet- 21 Drafts. 23 Internet-Drafts are draft documents valid for a maximum of six months 24 and may be updated, replaced, or obsoleted by other documents at any 25 time. It is inappropriate to use Internet-Drafts as reference 26 material or to cite them other than as "work in progress." 28 The list of current Internet-Drafts can be accessed at 29 http://www.ietf.org/ietf/1id-abstracts.txt. 31 The list of Internet-Draft Shadow Directories can be accessed at 32 http://www.ietf.org/shadow.html. 34 This Internet-Draft will expire on December 22, 2006. 36 Copyright Notice 38 Copyright (C) The Internet Society (2006). 40 Abstract 42 The Dynamic MANET On-demand (DYMO) routing protocol is intended for 43 use by mobile nodes in wireless multihop networks. It offers 44 adaptation to changing network topology and determines unicast routes 45 between nodes within the network on-demand. 47 Table of Contents 49 1. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 50 2. Applicability . . . . . . . . . . . . . . . . . . . . . . . . 4 51 3. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 5 52 4. Data Structures . . . . . . . . . . . . . . . . . . . . . . . 6 53 4.1. Route Table Entry . . . . . . . . . . . . . . . . . . . . 6 54 4.2. DYMO Messages . . . . . . . . . . . . . . . . . . . . . . 7 55 4.2.1. Generalized MANET Packet and Message Structure . . . . 7 56 4.2.2. Routing Message (RM) . . . . . . . . . . . . . . . . . 8 57 4.2.3. Route Error (RERR) . . . . . . . . . . . . . . . . . . 10 58 5. Detailed Operation . . . . . . . . . . . . . . . . . . . . . . 12 59 5.1. DYMO Sequence Numbers . . . . . . . . . . . . . . . . . . 12 60 5.1.1. Maintaining A Node's Own Sequence Number . . . . . . . 12 61 5.1.2. Incrementing a Sequence Number . . . . . . . . . . . . 13 62 5.1.3. Sequence Number Rollover . . . . . . . . . . . . . . . 13 63 5.1.4. Actions After Sequence Number Loss . . . . . . . . . . 13 64 5.2. DYMO Routing Table Operations . . . . . . . . . . . . . . 13 65 5.2.1. Judging New Routing Information's Usefulness . . . . . 13 66 5.2.2. Updating a Route Table Entry with Fresh Routing 67 Information . . . . . . . . . . . . . . . . . . . . . 14 68 5.2.3. Route Table Entry Timeouts . . . . . . . . . . . . . . 15 69 5.3. Routing Message . . . . . . . . . . . . . . . . . . . . . 15 70 5.3.1. RREQ Creation . . . . . . . . . . . . . . . . . . . . 15 71 5.3.2. RREP Creation . . . . . . . . . . . . . . . . . . . . 16 72 5.3.3. RM Processing . . . . . . . . . . . . . . . . . . . . 16 73 5.3.4. Adding Additional Routing Information to a RM . . . . 18 74 5.4. Route Discovery . . . . . . . . . . . . . . . . . . . . . 18 75 5.5. Route Maintenance . . . . . . . . . . . . . . . . . . . . 19 76 5.5.1. Active Link Monitoring . . . . . . . . . . . . . . . . 19 77 5.5.2. Updating Route Lifetimes during Packet Forwarding . . 20 78 5.5.3. Route Error Generation . . . . . . . . . . . . . . . . 20 79 5.5.4. Route Error Processing . . . . . . . . . . . . . . . . 21 80 5.6. General DYMO Packet and Message Processing . . . . . . . . 21 81 5.6.1. Receiving Packets . . . . . . . . . . . . . . . . . . 21 82 5.6.2. Processing Unknown Message and TLV Types . . . . . . . 21 83 5.7. Network Addresses . . . . . . . . . . . . . . . . . . . . 22 84 5.8. Simple Internet Attachment and Gatewaying . . . . . . . . 22 85 5.9. Multiple Interfaces . . . . . . . . . . . . . . . . . . . 23 86 5.10. Packet Generation Limits . . . . . . . . . . . . . . . . . 24 87 6. Configuration Parameters . . . . . . . . . . . . . . . . . . . 24 88 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 24 89 7.1. DYMO Message Type Specification . . . . . . . . . . . . . 25 90 7.2. Packet TLV Type Specification . . . . . . . . . . . . . . 25 91 7.3. Address Block TLV Specification . . . . . . . . . . . . . 26 92 8. Security Considerations . . . . . . . . . . . . . . . . . . . 26 93 9. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 27 94 10. References . . . . . . . . . . . . . . . . . . . . . . . . . . 27 95 10.1. Normative References . . . . . . . . . . . . . . . . . . . 27 96 10.2. Informative References . . . . . . . . . . . . . . . . . . 28 97 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 29 98 Intellectual Property and Copyright Statements . . . . . . . . . . 30 100 1. Overview 102 The Dynamic MANET On-demand (DYMO) routing protocol enables reactive, 103 multihop routing between participating nodes that wish to 104 communicate. The basic operations of the DYMO protocol are route 105 discovery and route management. During route discovery the 106 originating node initiates dissemination of a Route Request (RREQ) 107 throughout the network to find the target node. During this 108 dissemination process, each intermediate node records a route to the 109 originating node. When the target node receives the RREQ, it 110 responds with a Route Reply (RREP) unicast toward the originating 111 node. Each node that receives the RREP records a route to the target 112 node, and then the RREP is unicast toward the originating node. When 113 the originating node receives the RREP, routes have then been 114 established between the originating node and the target node in both 115 directions. 117 In order to react to changes in the network topology nodes maintain 118 their routes and monitor their links. When a data packet is received 119 for a route or link that is no longer available the source of the 120 packet is notified. A Route Error (RERR) is sent to the packet 121 source to indicate the current route is broken. Once the source 122 receives the RERR, it can perform route discovery if it still has 123 packets to deliver. 125 DYMO uses sequence numbers as they have been proven to ensure loop 126 freedom [Perkins99]. Sequence numbers enable nodes to determine the 127 order of DYMO route discovery messages, thereby avoiding use of stale 128 routing information. 130 2. Applicability 132 The DYMO routing protocol is designed for mobile ad hoc networks in 133 small, medium, and large node populations. DYMO handles all mobility 134 ranges. DYMO can handle various traffic patterns, but is most suited 135 for sparse traffic sources and destinations. DYMO is designed for 136 network where trust is assumed, since it depends on nodes properly 137 forwarding traffic to the next hop toward the destination on behalf 138 of the source. 140 DYMO is applicable to memory constrained devices, since little 141 routing state needs to be maintained. Only routing information 142 related to active destinations must be maintained, as opposed to 143 other routing protocols where routing information to all destinations 144 or a large population destinations must be maintained. 146 The routing algorithm in DYMO may be operated at layers other than 147 the network layer, using layer-appropriate addresses. Only 148 modification of the packet format is required. The routing algorithm 149 need not change. 151 3. Terminology 153 The keywords "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL 154 NOT","SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in 155 this document are to be interpreted as described in RFC2119 156 [RFC2119]. 158 This document defines the following terminology: 160 DYMO Sequence Number (SeqNum) 161 A DYMO Sequence Number is maintained by each node. This sequence 162 number is used to identify the freshness of related routing 163 information and to ensure loop-free routes. 165 Hop Count (HopCnt) 166 The number of IP hops a message or piece of information must 167 traverse to reach the node holding this information. 169 Originator (Orig) 170 The originator is the node that created a DYMO Message in an 171 effort to disseminate information. 173 Route Error (RERR) 174 A node generates a RERR to disseminate that it does not have valid 175 route to a particular destination, or set of destinations. 177 Route Reply (RREP) 178 Upon receiving a RREQ during route discovery, the target node 179 generates a Route Reply (RREP). A RREP is used to disseminate 180 routing information, on how to reach the target, to nodes between 181 the target and the RREQ originator. 183 Route Request (RREQ) 184 A node generates a RREQ to discover a valid route to a particular 185 destination, called the target. A RREQ also disseminates routing 186 information on how to reach the originator of the RREQ. 188 Target 189 The target node is the ultimate destination of a message. For 190 RREQ the target is the desired destination. For RREP the target 191 is the originator of the RREQ. 193 Valid Route 194 A valid route is a known route where the Route.ValidTimeout is 195 greater than the current time. Valid routes may be used to 196 forward data. 198 When describing DYMO messages, information found in the: 200 IP header is proceeded with 'IP.' 202 UDP header is proceeded with 'UDP.' 204 packetbb message header is proceeded with 'MsgHdr.' 206 packetbb message TLVs is proceeded with 'MsgTLV.' 208 packetbb address blocks is proceeded with 'AddBlk.' 210 packetbb address block TLVs is proceeded with 'AddTLV.' 212 4. Data Structures 214 4.1. Route Table Entry 216 The route table entry is a conceptual data structure. 217 Implementations may use any internal representation that conforms to 218 the semantics of a route as specified in this document. The number 219 zero (0) is reserved and can be used to indicate that the field value 220 for this routing entry is unknown or invalid. 222 A routing table entry has the following fields: 224 Route.Address 225 The IP destination address of the node associated with the routing 226 table entry. 228 Route.SeqNum 229 The DYMO SeqNum associated with this routing information. 231 Route.NextHopAddress 232 The IP address of the next node on the path toward the 233 Route.Address. 235 Route.NextHopInterface 236 The interface used to send packets toward the Route.Address. 238 Route.ValidTimeout 239 The time at which a route table entry is no longer valid. 241 Route.DeleteTimeout 242 If the current time is after Route.DeleteTimeout the corresponding 243 routing table entry MUST be deleted. 245 The following fields are optional: 247 Route.HopCnt 248 The number of intermediate node hops traversed before reaching the 249 Route.Address node. 251 Route.IsInternetGateway 252 1-bit selector indicating whether the Route.Address is a an 253 Internet gateway, see Section 5.8. 255 Route.Prefix 256 Indicates that the associated address is a network address, rather 257 than a host address. The value is the length of the netmask/ 258 prefix. If prefix is set to zero (0), unknown, or equal to the 259 address length in bits, this address is a host address. The 260 definition of Route.Prefix is different for gateways; entries with 261 Route.IsInternetGateway set to one (1), seeSection 5.8. 263 Route.Used 264 1-bit selector indicating whether this Route has been used to 265 forward data toward the destination. 267 Not including this optional information may result in sub-optimal 268 performance, but it is not required for correct protocol operation. 270 4.2. DYMO Messages 272 4.2.1. Generalized MANET Packet and Message Structure 274 All DYMO messages conform to the generalized packet and message 275 format as described in[I-D.ietf-manet-packetbb]. 277 All DYMO messages are sent using UDP to the destination port TBD. 279 All DYMO messages are sent with the IP destination address set to the 280 link local multicast address LL_ALL_MANET_ROUTER unless otherwise 281 stated. 283 The IP TTL (IP Hop Limit) field for all DYMO messages is set to one 284 (1). 286 The length of IP addresses (32-bits for IPv4 and 128-bits for IPv6) 287 inside DYMO messages are dependent on the IP packet header. For 288 example, if the IP header uses IPv6 addresses then all messages and 289 addresses contained in the payload use IPv6 addresses. In the case 290 of mixed IPv6 and IPv4 addresses, IPv4 addresses are carried in IPv6 291 as specified in [RFC3513]. 293 4.2.2. Routing Message (RM) 295 Routing Messages (RM) are used to disseminate routing information. 296 There are two DYMO message types that are RM, RREQ and RREP. They 297 contain the same information, but have slightly different processing 298 rules. The fundamental difference between the two messages are that 299 RREQ messages require a response; while a RREP is the response to 300 RREQ. 302 RM creation and processing are described in Section 5.3. 304 A RM requires the following information: 306 IP.DestinationAddress 307 The IP address of the packet destination. 309 MsgHdr.HopLimit 310 The remaining number of hops this message may traverse. 312 AddBlk.Target.Address 313 The IP address of the message target. In RREQ the target is the 314 unknown destination. In RREP the target is the RREQ originator. 315 Only one address can be marked as the target. 317 AddBlk.Orig.Address 318 The IP address of the message originator. This address is in an 319 address block and not in the message header to allow for address 320 compression and additional AddTLVs. 322 AddTLV.Orig.SeqNum 323 The DYMO sequence number of the message originator. 325 A RM may optionally include the following information: 327 AddTLV.Target.SeqNum 328 The last known DYMO sequence number of the target. If the 329 AddTLV.Target.SeqNum is set to zero (0), then only the destination 330 may respond to this RREQ. 332 AddBlk.AdditionalNode.Address 333 The IP address of an additional node that can be reached via the 334 node adding this information. Each AdditionalNode.Address must 335 have an associated SeqNum in the message. 337 AddTLV.AdditionalNode.SeqNum 338 The DYMO sequence number of the additional node's routing 339 information. 341 AddTLV.Node.HopCnt 342 The number of IP hops to reach the associated Node.Address. 344 AddTLV.Node.Prefix 345 The Node.Address is a network address ([I-D.ietf-manet-packetbb]). 347 AddTLV.Node.IsGateway 348 This AddTLV indicates that the Internet is reachable via this 349 node. That is, all nodes outside this Node's prefix are reachable 350 via the advertising Node. 352 AddTLV.Node.IsTarget 353 If the target is not the first address in the address blocks, this 354 AddTLV is used to indicate the target. 356 AddTLV.Node.IsOriginator 357 In the event that the originator is not the second address in the 358 address blocks, this AddTLV is used to indicate the originator. 360 AddTLV.AdditionalNode.IsOffPath 361 This AddTLV is used to indicate that a node is not on the path 362 between the originator and the target. 364 AddTLV.Node.Ignore 365 If the information associated with this Node.Address should not be 366 used create or update a route, this flag is set. 368 Not including this optional information may result in sub-optimal 369 performance, but it is not required for correct protocol operation. 371 Example IPv4 RREQ 373 0 1 2 3 374 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 1 376 IP Header 377 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 378 | IP.DestinationAddress=LL_ALL_MANET_ROUTERS | 379 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 380 ... 382 UDP Header 383 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 384 | Destination Port=TBD | 385 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 386 ... 387 Message Header 388 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 389 | RREQ-type | Resv |0|0|1| msg-size=24 | 390 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 391 | msg-hoplimit | msg-hopcnt | msg-tlv-block-size=0 | 392 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 393 ... 394 Address Block 395 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 396 |Number Addrs=2 |0|HeadLength=24| Head : 397 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 398 : Head (cont) | Target.Tail | Orig.Tail | TLV-blk-size : 399 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 400 : size=7 (cont) | 401 +-+-+-+-+-+-+-+-+ 402 ... 403 Address TLVs 404 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 405 |DYMOSeqNum-type| Resv |1|0|0|0| Index Start=1 | Index Stop=1 | 406 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 407 | tlv-length=16 | Orig.SeqNum | 408 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 410 Figure 1 412 4.2.3. Route Error (RERR) 414 RERR are used to disseminate that a valid route is not available for 415 a particular destination, or set of destinations. 417 RERR creation and processing are described in Section 5.5.3 and 418 Section 5.5.4. 420 A RERR requires the following information: 422 IP.DestinationAddress 423 The IP address of the packet destination. 425 MsgHdr.HopLimit 426 The remaining number of hops this message may traverse. 428 AddBlk.Unreachable.Address 429 The IP address of an Unreachable Node. Multiple Unreachable 430 Addresses may be included. If a SeqNum for this address is not 431 included, it is assumed to be unknown. 433 A Route Error may optionally include the following information: 435 AddTLV.Unreachable.SeqNum 436 The DYMO sequence number of the Unreachable Node. 438 AddTLV.Node.Ignore 439 If the information associated with Node.Address should not be used 440 to invalidate routes, this flag is set. 442 Example IPv4 RERR 444 0 1 2 3 445 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 1 447 IP Header 448 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 449 | IP.DestinationAddress=LL_ALL_MANET_ROUTERS | 450 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 451 ... 453 UDP Header 454 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 455 | Destination Port=TBD | 456 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 457 ... 458 Message Header 459 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 460 | RERR-type | Resv |0|0|1| msg-size=16 | 461 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 462 | msg-hoplimit | msg-hopcnt | msg-tlv-block-size=0 | 463 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 464 ... 465 Address Block 466 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 467 |Number Addrs=1 |0|HeadLength=0 | Unreachable.Addr : 468 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 469 : Unreachable.Addr (cont) | TLV-blk-size=0 | 470 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 472 Figure 2 474 5. Detailed Operation 476 5.1. DYMO Sequence Numbers 478 DYMO sequence numbers allow nodes to judge the freshness of routing 479 information, and ensure loop freedom. 481 5.1.1. Maintaining A Node's Own Sequence Number 483 DYMO requires a each node in the network to maintain its own DYMO 484 sequence number (OwnSeqNum), a 16-bit unsigned integer. The 485 circumstances for a node to incrementing its OwnSeqNum are described 486 in Section 5.3. 488 5.1.2. Incrementing a Sequence Number 490 When a node increments its OwnSeqNum (as described in Section 5.3) it 491 MUST do so by treating the sequence number value as if it was an 492 unsigned number. The sequence number zero (0) is reserved and is 493 used in several DYMO data structures to represent an unknown sequence 494 number. 496 5.1.3. Sequence Number Rollover 498 If the sequence number has been assigned to be the largest possible 499 number representable as a 16-bit unsigned integer (i.e., 65535), then 500 the sequence number MUST be set to 256 when incremented. Setting the 501 sequence number to 256 allows other nodes to detect that the number 502 has rolled over and the node has not lost its sequence number. 504 5.1.4. Actions After Sequence Number Loss 506 A node can maintain its sequence number in persistent storage, 507 between reboots. 509 If a node's OwnSeqNum is lost, it must take certain actions to avoid 510 creating routing loops. To prevent this possibility after OwnSeqNum 511 loss a node MUST wait for at least ROUTE_DELETE_PERIOD before fully 512 participating in the DYMO routing protocol. If a DYMO control 513 message is received during this waiting period, the node SHOULD 514 process it normally but MUST not transmit or retransmit any DYMO 515 messages. If a data packet is received for forwarding to another 516 destination during this waiting period, the node MUST generate a RERR 517 message indicating that this route is not available and reset its 518 waiting period. RERR generation is described in Section 5.5.3. At 519 the end of the waiting period a node sets its OwnSeqNum to one (1). 521 5.2. DYMO Routing Table Operations 523 5.2.1. Judging New Routing Information's Usefulness 525 Given a routing table entry (Route.SeqNum, Route.HopCnt, and 526 Route.ValidTimeout) and new routing information for a particular node 527 in a RM (Node.SeqNum, Node.HopCnt, and RM message type - RREQ/RREP), 528 the quality of the new routing information is evaluated to determine 529 its usefulness. The following comparisons are performed in order: 531 1. Stale 532 If Node.SeqNum - Route.SeqNum < 0 (using signed 16-bit arithmetic) 533 the information is stale. Using stale routing information is not 534 allowed, since doing so might result in routing loops. 536 2. Loop-prone 537 If Node.SeqNum == Route.SeqNum the information maybe loop-prone, 538 additional information must be examined. If Route.HopCnt is 539 unknown or set to zero (0), then the routing information is loop- 540 prone. Likewise, if Node.HopCnt is unknown or set to zero (0), 541 then the routing information is loop-prone. If Node.HopCnt > 542 Route.HopCnt + 1, then the routing information is loop-prone. 543 Using loop-prone routing information is not allowed, since doing 544 so might result in routing loops. 546 3. Inferior 547 If Node.SeqNum == Route.SeqNum the information may be inferior, 548 additional information must be examined. If the route is valid 549 (by examining Route.ValidTimeout and the current time), then the 550 new information is inferior if Node.HopCnt > Route.HopCnt. If the 551 route is valid, then the new information is also inferior if 552 Node.HopCnt == Route.HopCnt AND this RM is a RREQ. 554 4. Fresh 555 Routing information that does not match any of the above criteria 556 is loop-free and better than the information existing in the 557 routing table. Only this type of information is used to update 558 the routing table. 560 5.2.2. Updating a Route Table Entry with Fresh Routing Information 562 If fresh routing information is received, the routing table entry is 563 populated with the following information: 565 1. the Route.Address is set to Node.Address, 567 2. the Route.SeqNum is set to the Node.SeqNum, 569 3. the Route.NextHopAddress is set to the node that transmitted this 570 DYMO packet (IP.SourceAddress), 572 4. the Route.NextHopInterface is set to the interface that this DYMO 573 packet was received on, 575 5. the Route.ValidTimeout is set to the current time + 576 ROUTE_VALID_TIMEOUT, 578 6. the Route.HopCnt is set to the Node.HopCnt, 580 7. the Route.Prefix is set to the Node.Prefix, 582 8. the Route.IsInternetGateway is set if address is an Internet 583 Gateway. 585 Unknown values are set to zero (0). 587 If a valid route exists to Node.Address at this point, the route can 588 be used to send any queued data packets and to fulfill any 589 outstanding RREQ. 591 5.2.3. Route Table Entry Timeouts 593 Before using a routing table entry its timeouts must be examined. 595 If the current time is after Route.DeleteTimeout the corresponding 596 routing table entry MUST be deleted. 598 If the current time is later than a routing entry's 599 Route.ValidTimeout, the route is stale and cannot be used to route 600 packets. The information in invalid entries is still used for 601 filling fields in outgoing RM with last known values. 603 5.3. Routing Message 605 5.3.1. RREQ Creation 607 When a node creates a RREQ it SHOULD increment its OwnSeqNum by one 608 (1) according to the rules specified in (Section 5.1.2). 610 Fist, the node adds the AddBlk.Target.Address to the RM. 612 If a previous value of the Target.SeqNum is known (from an existing 613 routing table entry), it SHOULD be placed in AddTLV.Target.SeqNum. 614 If a Target.SeqNum is not included, it is assumed to be unknown by 615 processing nodes and only the target is allowed to respond. A 616 Target.SeqNum of zero (0) MAY be set to indicate that any node with 617 valid routing information about this destination can respond to this 618 RREQ if the node is so enabled, though the process for doing so is 619 not described in this document. 621 Similarly, if a previous value of the Target.HopCnt is known, it 622 SHOULD be placed in AddTLV.Target.HopCnt. Otherwise, the HopCnt is 623 not included and assumed unknown by processing nodes. 625 These AddTLVs associated with the target SHOULD be set to maximum 626 protocol efficiency, but they may be omitted to reduce message size. 628 Next, the node adds AddBlk.Orig.Address to the RM and the 629 AddTLV.Orig.SeqNum (OwnSeqNum) in an address block TLV. The 630 Orig.Address is this node's primary addresses/identifier. The 631 Orig.Address must be a routable IP address. 633 Other AddTLVs for the originator SHOULD be set to maximum protocol 634 efficiency, but they may be omitted to reduce message size. 636 The MsgHdr.HopCnt is set to zero (0). The MsgHdr.HopLimit SHOULD be 637 set to NET_DIAMETER, but MAY be set smaller. For RREQ, the 638 MsgHdr.HopLimit MAY be set in accordance with an expanding ring 639 search as described in [RFC3561] to limit the RREQ propagation to a 640 subset of the network and possibly reduce route discovery overhead. 642 5.3.2. RREP Creation 644 When a node creates a RREP in response to a RREQ, it MUST increment 645 its OwnSeqNum under the following conditions: 647 o Target.SeqNum is not included in the message, OR 649 o Target.SeqNum is zero (0), OR 651 o Target.SeqNum - OwnSeqNum > 0 (using 16-bit signed arithmetic), OR 653 o Target.SeqNum == OwnSeqNum AND Target.HopCnt is unknown, OR 655 o Target.SeqNum == OwnSeqNum AND Orig.HopCnt is unknown, OR 657 o Target.SeqNum == OwnSeqNum AND Target.HopCnt (the last know hop 658 count value) < Orig.HopCnt (the number of hops traversed by this 659 RREQ to reach the target). 661 First, the node adds the AddBlk.Target.Address to the RM. The 662 Target.Address is copied from the incoming RREQ AddBlk.Orig.Address. 664 Next, the node adds the AddBlk.Orig.Address to the RM and the 665 AddTLV.Orig.SeqNum (OwnSeqNum) in an address block TLV. The 666 Orig.Address is copied from the incoming RREQ AddBlk.Target.Address. 668 Other AddTLVs for the originator and target SHOULD be set to maximum 669 protocol efficiency, but they may be omitted to reduce message size. 671 The MsgHdr.HopCnt is set to zero (0). The MsgHdr.HopLimit is set to 672 NET_DIAMETER. 674 5.3.3. RM Processing 676 When a RM is received the MsgHdr.HopLimit is decremented by one (1) 677 and MsgHdr.HopCnt is incremented by one (1). 679 For each address in the RM that includes AddTLV-HopCnt information 680 except the target and those addresses tagged with the AddTLV-Ignore, 681 the AddTLV-HopCnt information is incremented by one (1). 683 Next, this node checks whether its routing table has an entry to the 684 AddBlk.Orig.Address using longest-prefix matching [RFC1812]. If a 685 route does not exist, the new routing information is considered fresh 686 and a new route table entry is created and updated as described in 687 Section 5.2.2. If a routing table entry exists, the new node's 688 information is compared with the route table entry following the 689 procedure described in Section 5.2.1. If the new node's routing 690 information is considered fresh, the route table entry is updated as 691 described in Section 5.2.2. 693 If the routing information for the originator is not fresh then this 694 RM must be discarded and no further processing of this message is 695 performed. 697 If the originator's routing information was considered fresh, then 698 each address that is not the target and is not flagged with the 699 Ignore address-block-tlv SHOULD considered for creating and updating 700 routes. If routing table space is limited, only the routing 701 information about the originator is required. Creating and updating 702 routes for other locations can eliminate RREQ for those destination, 703 in the event that data needs to be forwarded to these destinations in 704 the near future. 706 For each of these addresses considered, if the routing table does not 707 have a matching route using longest-prefix matching, then a route is 708 created and updated as described in Section 5.2.2. If a routing 709 table entry exists, the new node's information is compared with the 710 route table entry following the procedure described in Section 5.2.1. 711 If the new node's routing information is considered fresh, the route 712 table entry is updated as described in Section 5.2.2. 714 If the routing information for an Node.Address is not considered 715 fresh, then if MUST be removed from the RM. Removing this 716 information ensures that non-fresh information is not propagated. 718 If this node is the target AND this RM is a RREQ, this node responds 719 with a RREP. This node creates a new RREP as described in 720 Section 5.3.2. 722 After processing a RM or creating a new RM, a node MAY append 723 additional routing information to the RM, according to the process 724 described in Section 5.3.4. The additional routing information will 725 help reduce route discoveries at the expense of increased message 726 size. 728 If this RM's MsgHdr.HopLimit is greater than one (1), this node is 729 not the target, AND this RM is a RREQ, then the current RM (altered 730 by the process defined above) SHOULD be sent to the 731 LL_ALL_MANET_ROUTERS IP.DestinationAddress. 733 If this RM's MsgHdr.HopLimit is greater than one (1), this node is 734 not the target, AND this RM is a RREP, then the new RM SHOULD be sent 735 to the Route.NextHopAddress for the RREP's Target.Address. 737 If this node is the target, the current RM's information is not 738 retransmitted. 740 5.3.4. Adding Additional Routing Information to a RM 742 Appending routing information will alleviate route discovery attempts 743 to the nodes whose information is included, if other nodes use this 744 information to update their routing tables. 746 Nodes MAY append routing information to a RM, if the node believe 747 that this additional routing information will alleviate future RREQ. 748 This option should be administratively controlled. 750 Prior to appending their own address to a RM, a node MUST increment 751 its OwnSeqNum as defined in Section 5.1.2. Then the node appends its 752 IP address (AddBlk-Address) and OwnSeqNum (AddTLV-SeqNum). It MAY 753 also append other information to its address, such as prefix and/or 754 that it is an Internet Gateway. If included, the Node.HopCnt is set 755 to one (1). 757 Routing information about other nodes MAY also be added. If this 758 information is included, it must be flagged with the 759 AddTLV.AdditionalNode.IsOffPath. 761 Note an address may appear only once in a message's address blocks. 762 Prior to adding any address, the message is searched for existing 763 entries. If an existing entry exists, this entry will have the 764 information as this node's routing table information (created or 765 updated while processing the RM) and therefore no update is 766 necessary. 768 In the event a newly appended address already has an AddTLV-Ignore 769 flag set, it is removed. 771 5.4. Route Discovery 773 A node creates a RREQ (described in Section 5.3.1) to discover a 774 route to a particular destination (target). The 775 IP.DestinationAddress for this RREQ is set to the 776 LL_ALL_MANET_ROUTERS. Then the RM is transmitted. 778 After issuing a RREQ, the originating node waits for a route to be 779 created to the target. If a route is not found within RREQ_WAIT_TIME 780 milliseconds, this node MAY again try to discover a route by issuing 781 another RREQ. 783 To reduce congestion in a network, repeated attempts at route 784 discovery for a particular target SHOULD utilize a binary exponential 785 backoff. The first time a node issues a RREQ, it waits 786 RREQ_WAIT_TIME milliseconds for a route to the target. If a route is 787 not found within that time, the node MAY send another RREQ. If a 788 route is not found within two (2) times the current waiting time, 789 another RREQ may be sent, up to a total of RREQ_TRIES. For each 790 additional attempt, the waiting time for the previous RREQ is 791 multiplied by two (2) so that the waiting time conforms to a binary 792 exponential backoff. 794 Data packets awaiting a route SHOULD be buffered. This buffer SHOULD 795 have a fixed limited size and discard older data packets first. 797 If a route discovery has been attempted RREQ_TRIES times without 798 receiving a route to the target, all data packets destined for the 799 corresponding target are dropped from the buffer and a Destination 800 Unreachable ICMP message SHOULD be delivered to the application. 802 5.5. Route Maintenance 804 A RERR MUST be issued if a data packet is received and it cannot be 805 delivered to the next hop, RERR generation is described in 806 Section 5.5.3. A RERR MAY be issued immediately after detecting a 807 broken link of an active route to quickly notify nodes that a link 808 break occurred and certain routes are no longer available. If a 809 route has not been used, a RERR SHOULD NOT be generated unless 810 generation is expected to reduce future traffic. 812 5.5.1. Active Link Monitoring 814 Nodes MUST monitor links on active routes that are being used. This 815 may be accomplished by one or several mechanisms. Including: 817 o Link layer feedback 819 o Neighborhood discovery [I-D.ietf-manet-nhdp] 821 o Route timeout 823 o Other monitoring mechanisms or heuristics 825 Upon detecting a link break the detecting node MUST set the 826 Route.ValidTimeout to the current time for all active routes 827 utilizing the broken link. 829 5.5.2. Updating Route Lifetimes during Packet Forwarding 831 To avoid route timeouts for active routes, a node SHOULD update the 832 Route.ValidTimeout for the IP.SourceAddress to be the current time + 833 ROUTE_VALID_TIMEOUT upon receiving a data packet. This route's 834 Route.Used bit is also set, if implemented. 836 To avoid route timeouts for active routes, a node SHOULD update the 837 Route.ValidTimeout for the IP.DestinationAddress to be the current 838 time + ROUTE_VALID_TIMEOUT upon successfully transmitting a packet to 839 the next hop. This route's Route.Used bit is also set. 841 5.5.3. Route Error Generation 843 When a data packet is received for a destination without a valid 844 routing table entry, a RERR MUST be generated. When a RREP is being 845 transmitted and no active route to the target exists, a RERR MUST be 846 generated. A RERR informs the IP.SourceAddress that the route does 847 not exist, is no longer available, or is now invalid. 849 In a new RERR, the address of first unreachable node 850 (IP.DestinationAddress from the data packet) is inserted. If a value 851 for the unreachable node's SeqNum (AddTLV-SeqNum) is known, it SHOULD 852 be placed in the RERR. The MsgHdr.HopLimit is set to NET_DIAMETER. 853 The MsgHdr.HopCnt is set to one (1). 855 Additional unreachable nodes that required the same unavailable link 856 (routes with the same Route.NextHopAddress and 857 Route.NextHopInterface) MAY be added to the RERR. The SeqNum if know 858 SHOULD also be included. Appending unreachable node information 859 notifies each processing node of additional routes that are no longer 860 available. 862 If SeqNum information is not known or not included all nodes 863 processing the routing information will assume their routing 864 information associated with the unreachable node is no longer valid. 866 The RERR is sent to the IP.DestinationAddress LL_ALL_MANET_ROUTERS. 867 Sending the RERR to the LL_ALL_MANET_ROUTERS address notifies the 868 maximum number of nodes of the broken link. 870 The packet or message that forced generation of this RERR is 871 discarded. 873 5.5.4. Route Error Processing 875 When a node processes a RERR, it processes each unreachable node 876 address. It sets the Route.ValidTimeout to the current time for each 877 Address found using longest prefix matching that meet all of the 878 following conditions: 880 1. The Route.NextHopAddress is the same as the RERR 881 IP.SourceAddress. 883 2. The Route.NextHopInterface is the same as the interface on which 884 the RERR was received. 886 3. The Route.SeqNum is zero (0), unknown, OR the Node.SeqNum is zero 887 (0), unknown, OR Node.SeqNum - Route.SeqNum <= 0 (using signed 888 16-bit arithmetic). 890 Each unreachable node that did not result in a change to 891 Route.ValidTimeout is removed from the RERR, since propagation of 892 this information will not result in any benefit. Any information 893 associated with the removed addresses is also removed. 895 If no unreachable node addresses remain, no further processing is 896 performed. 898 If this RERR's MsgHdr.HopLimit is greater than one (1) and at least 899 one unreachable node address remains in the RERR, then the RERR is 900 sent to the IP.DestinationAddress LL_ALL_MANET_ROUTERS. 902 Addresses marked with AddTLV-Ignore should remain in the RERR. 904 5.6. General DYMO Packet and Message Processing 906 5.6.1. Receiving Packets 908 When a packet is received, its PktTLV are first examined. Next each 909 message is examined and processed in order. 911 Each message's headers are first examined. Next, the MsgTLV are 912 examined. Finally, each message is processed according to its 913 MsgHdr.type. 915 5.6.2. Processing Unknown Message and TLV Types 917 To allow future extensions, DYMO uses bits from the semantics fields 918 of PktTLV, Message, MsgTLV, and AddTLV [I-D.ietf-manet-packetbb]. 919 Note [I-D.ietf-manet-packetbb] does not currently support this 920 functionality. 922 The semantic bits have the following names and characteristics for 923 nodes that do not understand the type. 925 Remove 926 If the Semantics.Remove-bit is set, this information SHOULD be 927 removed from the message. 929 Discard 930 If the Semantics.Discard-bit is set, this message SHOULD not be 931 processed further and it should not be propagated. In the case of 932 PktTLVs if the Semantics.Discard-bit is set, no messages from the 933 packet should be processed or propagated. 935 5.7. Network Addresses 937 Any node MAY advertise a network address by using a Prefix tlv 938 [I-D.ietf-manet-packetbb]. Any nodes (other than the advertising 939 node) within the advertised Prefix SHOULD NOT participate in the 940 MANET and these nodes MUST be reachable by forwarding packets to the 941 node advertising connectivity. For example, A.B.C.1 with a prefix 942 length of 24 indicates all nodes with the matching A.B.C.X are 943 reachable through the node with address A.B.C.1. 945 The meaning of the Prefix field is altered for theroute to an 946 Internet gateway; Route.IsInternetGateway is one (1). If the route 947 refers to an Internet gateway, its Prefix in association with the IP 948 address indicates that all nodes outside that subnet are reachable 949 via the Internet gateway node. For example, a route to a Internet 950 gateway with IP address A.B.C.1 and a prefix of 24 indicates that all 951 nodes with an IP address NOT matching A.B.C.X are reachable via this 952 node. 954 5.8. Simple Internet Attachment and Gatewaying 956 Simple Internet attachment consists of a network of MANET nodes 957 connected to the Internet via a single Internet gateway node. The 958 gateway is responsible for responding to RREQs for targets outside 959 its configured MANET subnet, as well as delivering packets to 960 destinations outside the MANET. 962 /--------------------------\ 963 / Internet \ 964 \ / 965 \------------+-------------/ 966 MANET Subnet | A.B.C.X 967 +-----+-----+ 968 | MANET | 969 /------| Internet |------\ 970 / | Gateway | \ 971 / | A.B.C.1 | \ 972 | +-----------+ | 973 | MANET | 974 | | 975 | +------------+ | 976 | | MANET Node | | 977 | | A.B.C.2 | | 978 | +------------+ | 979 | +------------+ | 980 | | MANET Node | | 981 | | A.B.C.3 | | 982 \ +------------+ / 983 \ / 984 \-------------------------/ 986 Figure 3: Simple Internet Attachament Example 988 MANET nodes wishing to be reachable from nodes in the Internet MUST 989 have IP addresses within the gateway's configured and advertised 990 MANET subnet. Given a node with a globally routeable address or 991 care-of address handled by the gateway, the gateway is responsible 992 for routing and forwarding packets received from the Internet 993 destined for nodes inside its MANET subnet. 995 Since many nodes may commonly wish to communicate with the gateway, 996 the gateway SHOULD indicate to nodes that it is a gateway by using 997 the gateway tlv in any RM transmitted. The Internet Gateway tlv 998 indicates to nodes in the MANET that the Node.Address is attached to 999 the Internet and is capable of routing data packets to all nodes 1000 outside of the configured MANET subnet, defined by the Node.Address 1001 and Node.Prefix fields. 1003 5.9. Multiple Interfaces 1005 It is likely that DYMO will be used with multiple wireless 1006 interfaces; therefore, the particular interface over which packets 1007 arrive must be known whenever a packet is received. Whenever a new 1008 route is created, the interface through which the Route.Address can 1009 be reached is also recorded in the route table entry. 1011 When multiple interfaces are available, a node transmitting a packet 1012 with IP.DestinationAddress set to LL_ALL_MANET_ROUTERS SHOULD send 1013 the packet on all interfaces that have been configured for DYMO 1014 operation. 1016 5.10. Packet Generation Limits 1018 To avoid congestion, a node SHOULD NOT transmit more than RATE_LIMIT 1019 control messages per second. RREQ packets SHOULD be discarded before 1020 RREP or RERR packets. 1022 6. Configuration Parameters 1024 Suggested Parameter Values 1026 +------------------------+-------------------------+ 1027 | Name | Value | 1028 +------------------------+-------------------------+ 1029 | NET_DIAMETER | 10 | 1030 | RATE_LIMIT | 10 | 1031 | ROUTE_VALID_TIMEOUT | 5000 milliseconds | 1032 | ROUTE_DELETE_TIMEOUT | 5 * ROUTE_VALID_TIMEOUT | 1033 | ROUTE_DELETE_PERIOD | 6 * ROUTE_VALID_TIMEOUT | 1034 | ROUTE_RREQ_WAIT_TIME | 1000 milliseconds | 1035 | RREQ_TRIES | 3 | 1036 +------------------------+-------------------------+ 1038 Table 1 1040 These suggested values work well for small and medium well connected 1041 networks with infrequence topology changes. For larger networks or 1042 networks with frequent topology changes the default DYMO parameters 1043 should be adjusted using either experimentally determined values or 1044 dynamic adaptation. For example, in networks with infrequent 1045 topology changes ROUTE_VALID_TIMEOUT may be set to a much larger 1046 value. 1048 It is assumed that all nodes in the network share the same parameter 1049 settings. Different parameter values for ROUTE_VALID_TIMEOUT or 1050 ROUTE_DELETE_TIMEOUT in addition to arbitrary packet delays may 1051 result in frequent route breaks or in extreme cases routing loops. 1053 7. IANA Considerations 1055 DYMO requires a UDP port number to carry protocol packets - TBD. 1056 DYMO also requires the link-local multicast address 1057 LL_ALL_MANET_ROUTERS; IPv4 TBD, IPv6 TBD. 1059 This section also specifies several messages types, message tlv- 1060 types, and address tlv-types. 1062 Future types will be allocated using standard actions as described in 1063 [RFC2434]. 1065 7.1. DYMO Message Type Specification 1067 The following address block TLV. 1069 DYMO Message Types 1071 +------------------------+----------+ 1072 | Name | Type | 1073 +------------------------+----------+ 1074 | Route Request (RREQ) | 10 - TBD | 1075 | Route Reply (RREP) | 11 - TBD | 1076 | Route Error (RERR) | 12 - TBD | 1077 +------------------------+----------+ 1079 Table 2 1081 7.2. Packet TLV Type Specification 1083 Packet TLV Types 1085 +-------------------+------+--------+-------------------------------+ 1086 | Name | Type | Length | Value | 1087 +-------------------+------+--------+-------------------------------+ 1088 | Unicast Response | TBD | 10 - | Indicates to the processing | 1089 | Request | | TBD | node that the previous hop | 1090 | | | | (IP.SourceAddress) expects a | 1091 | | | | unicast message within | 1092 | | | | UNICAST_MESSAGE_SENT_TIMEOUT. | 1093 | | | | Any unicast packet will serve | 1094 | | | | this purpose, and it MAY be | 1095 | | | | an ICMP REPLY message. If a | 1096 | | | | message is not sent, then the | 1097 | | | | previous hop may assume that | 1098 | | | | the link is unidirectional | 1099 | | | | and may blacklist this node. | 1100 +-------------------+------+--------+-------------------------------+ 1102 Table 3 1104 7.3. Address Block TLV Specification 1106 Address Block TLV Specification Overview 1108 +----------------------+------+--------+----------------------------+ 1109 | Name | Type | Length | Value | 1110 +----------------------+------+--------+----------------------------+ 1111 | DYMOSeqNum | 10 - | 16 | The DYMO sequence num | 1112 | | TBD | bits | associated with this | 1113 | | | | address. The sequence | 1114 | | | | number may be the last | 1115 | | | | known sequence number. | 1116 | HopCount | 11 - | 8 bits | The number of hops | 1117 | | TBD | | traversed by the | 1118 | | | | information associated | 1119 | | | | with this address. | 1120 | IsInternetGateway | 12 - | 0 bits | Usde to indicate that this | 1121 | | TBD | | node is an Internet | 1122 | | | | Gateway | 1123 | IsOriginator | 13 - | 0 bits | Used to indicate that this | 1124 | | TBD | | node is the Originator of | 1125 | | | | the RM. | 1126 | IsTarget | 14 - | 0 bits | Used to indicate this node | 1127 | | TBD | | is the target of the DYMO | 1128 | | | | message | 1129 | Ignore | 15 - | 0 | Used to indicate that this | 1130 | | TBD | | addresses should not be | 1131 | | | | processed normally; | 1132 | | | | instead it should be | 1133 | | | | ignored. | 1134 +----------------------+------+--------+----------------------------+ 1136 Table 4 1138 8. Security Considerations 1140 Currently, DYMO does not specify any special security measures. 1141 Routing protocols, however, are prime targets for impersonation 1142 attacks. In networks where the node membership is not known, it is 1143 difficult to determine the occurrence of impersonation attacks, and 1144 security prevention techniques are difficult at best. However, when 1145 the network membership is known and there is a danger of such 1146 attacks, DYMO messages must be protected by the use of authentication 1147 techniques, such as those involving generation of unforgeable and 1148 cryptographically strong message digests or digital signatures. 1149 While DYMO does not place restrictions on the authentication 1150 mechanism used for this purpose, IPsec Authentication Message (AH) is 1151 an appropriate choice for cases where the nodes share an appropriate 1152 security association that enables the use of AH. 1154 In particular, RM messages SHOULD be authenticated to avoid creation 1155 of spurious routes to a destination. Otherwise, an attacker could 1156 masquerade as that destination and maliciously deny service to the 1157 destination and/or maliciously inspect and consume traffic intended 1158 for delivery to the destination. RERR messages, while slightly less 1159 dangerous, SHOULD be authenticated in order to prevent malicious 1160 nodes from disrupting active routes between communicating nodes. 1162 If the mobile nodes in the ad hoc network have pre-established 1163 security associations, the purposes for which the security 1164 associations are created should include that of authorizing the 1165 processing of DYMO control packets. Given this understanding, the 1166 mobile nodes should be able to use the same authentication mechanisms 1167 based on their IP addresses as they would have used otherwise. 1169 9. Acknowledgments 1171 DYMO is a descendant of the design of previous MANET reactive 1172 protocols, especially AODV [RFC3561] and DSR [Johnson96]. Changes to 1173 previous MANET reactive protocols stem from research and 1174 implementation experiences. Thanks to Elizabeth Belding-Royer for 1175 her long time authorship of DYMO. Additional thanks to Luke Klein- 1176 Berndt, Pedro Ruiz, Fransisco Ros, Koojana Kuladinithi, Ramon 1177 Caceres, and Thomas Clausen for reviewing of DYMO, as well as several 1178 specification suggestions. 1180 10. References 1182 10.1. Normative References 1184 [RFC1812] Baker, F., "Requirements for IP Version 4 Routers", 1185 RFC 1812, June 1995. 1187 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 1188 Requirement Levels", BCP 14, RFC 2119, March 1997. 1190 [RFC2434] Narten, T. and H. Alvestrand, "Guidelines for Writing an 1191 IANA Considerations Section in RFCs", BCP 26, RFC 2434, 1192 October 1998. 1194 [RFC3513] Hinden, R. and S. Deering, "Internet Protocol Version 6 1195 (IPv6) Addressing Architecture", RFC 3513, April 2003. 1197 [RFC3561] Perkins, C., Belding-Royer, E., and S. Das, "Ad hoc On- 1198 Demand Distance Vector (AODV) Routing", RFC 3561, 1199 July 2003. 1201 10.2. Informative References 1203 [I-D.ietf-manet-nhdp] 1204 Clausen, T., Dearlove, C., and J. Dean, "MANET 1205 Neighborhood Discovery Protocol", draft-ietf-manet-nhdp-00 1206 (work in progress), June 2006. 1208 [I-D.ietf-manet-packetbb] 1209 Clausen, T., Dearlove, C., Dean, J., and C. Adjih, 1210 "Generalized MANET Packet/Message Format", 1211 draft-ietf-manet-packetbb-01 (work in progress), 1212 June 2006. 1214 [Johnson96] 1215 Johnson, D. and D. Maltz, "Dynamic Source Routing (DSR) in 1216 Ad hoc Networks", In Mobile Computing, Chapter 5, pp. 153- 1217 181, 1996. 1219 [Perkins99] 1220 Perkins, C. and E. Belding-Royer, "Ad hoc On-Demand 1221 Distance Vector (AODV) Routing", Proceedings of the 2nd 1222 IEEE Workshop on Mobile Computing Systems and 1223 Applications, New Orleans, LA, pp. 90-100, 1224 February 1999. 1226 Authors' Addresses 1228 Ian Chakeres 1229 Boeing Phantom Works 1230 The Boeing Company 1231 P.O. Box 3707 Mailcode 7L-49 1232 Seattle, WA 98124-2207 1233 USA 1235 Email: ian.chakeres@gmail.com 1237 Charlie Perkins 1238 Nokia Research Center 1239 313 Fairchild Drive 1240 Mountain View, CA 94043 1241 USA 1243 Phone: +1-650-625-2986 1244 Fax: +1-650-625-2502 1245 Email: charlie.perkins@nokia.com 1247 Intellectual Property Statement 1249 The IETF takes no position regarding the validity or scope of any 1250 Intellectual Property Rights or other rights that might be claimed to 1251 pertain to the implementation or use of the technology described in 1252 this document or the extent to which any license under such rights 1253 might or might not be available; nor does it represent that it has 1254 made any independent effort to identify any such rights. 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Please address the information to the IETF at 1269 ietf-ipr@ietf.org. 1271 Disclaimer of Validity 1273 This document and the information contained herein are provided on an 1274 "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS 1275 OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET 1276 ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED, 1277 INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE 1278 INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED 1279 WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. 1281 Copyright Statement 1283 Copyright (C) The Internet Society (2006). This document is subject 1284 to the rights, licenses and restrictions contained in BCP 78, and 1285 except as set forth therein, the authors retain all their rights. 1287 Acknowledgment 1289 Funding for the RFC Editor function is currently provided by the 1290 Internet Society.