idnits 2.17.1 draft-perlman-trill-rbridge-data-encoding-05.txt: Checking boilerplate required by RFC 5378 and the IETF Trust (see https://trustee.ietf.org/license-info): ---------------------------------------------------------------------------- No issues found here. Checking nits according to https://www.ietf.org/id-info/1id-guidelines.txt: ---------------------------------------------------------------------------- No issues found here. Checking nits according to https://www.ietf.org/id-info/checklist : ---------------------------------------------------------------------------- No issues found here. Miscellaneous warnings: ---------------------------------------------------------------------------- == The copyright year in the IETF Trust and authors Copyright Line does not match the current year (Using the creation date from RFC6325, updated by this document, for RFC5378 checks: 2006-05-11) -- 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 (April 4, 2016) is 2941 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) -- Possible downref: Non-RFC (?) normative reference: ref. 'IS-IS' Summary: 0 errors (**), 0 flaws (~~), 1 warning (==), 3 comments (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 1 TRILL Working Group Radia Perlman 2 INTERNET-DRAFT EMC 3 Updates: 6325 Donald Eastlake 4 Intended status: Proposed Standard Yizhou Li 5 Huawei 6 Anoop Ghanwani 7 Dell 8 Expires: October 3, 2016 April 4, 2016 10 RBridges: TRILL Link Data Optimizations 11 13 Abstract 15 TRILL (TRansparent Interconnection of Lots of Links) Data frames can 16 be encoded so as to make more efficient use of communications links 17 under certain circumstances. This document specifies two such 18 optional optimizations. One, called Compact Format, improves the 19 compactness of encoding where a TRILL link is a point-to-point 20 Ethernet link. The other, called Specific Addressing, optionally 21 decreases the burden on multi-access TRILL links for multi- 22 destination TRILL Data frames. This document updates RFC 6325. 24 Status of This Memo 26 This Internet-Draft is submitted to IETF in full conformance with the 27 provisions of BCP 78 and BCP 79. 29 Distribution of this document is unlimited. Comments should be sent 30 to the TRILL working group mailing list . 32 Internet-Drafts are working documents of the Internet Engineering 33 Task Force (IETF), its areas, and its working groups. Note that 34 other groups may also distribute working documents as Internet- 35 Drafts. 37 Internet-Drafts are draft documents valid for a maximum of six months 38 and may be updated, replaced, or obsoleted by other documents at any 39 time. It is inappropriate to use Internet-Drafts as reference 40 material or to cite them other than as "work in progress." 42 The list of current Internet-Drafts can be accessed at 43 http://www.ietf.org/1id-abstracts.html. The list of Internet-Draft 44 Shadow Directories can be accessed at 45 http://www.ietf.org/shadow.html. 47 Table of Contents 49 1. Introduction............................................3 50 1.1 Structure of This Document.............................3 51 1.2 Terminology Used in This Document......................4 53 2. TRILL Frame Formats.....................................5 54 2.1 The General TRILL Frame Format.........................5 55 2.2 Ethernet Link TRILL Data Frame General Encapsulation...6 57 3. Compact Format for Point-to-Point Ethernet Links........8 58 3.1 Conditions for Using Compact Format....................8 59 3.2 RBridge Originated and Terminated Native Frames.......10 60 3.3 Compact TRILL Data Reception and Transmission.........10 61 3.3.1 Compact TRILL Data Frame Reception..................10 62 3.3.2 Compact TRILL Data Frame Transmission...............12 63 3.4 Announcing Support for Compact Format.................12 65 4. Specific Addressing....................................13 66 4.1 Current Multi-Destination Addressing..................13 67 4.2 Specific Addressing Specification.....................13 68 4.3 Announcing Support for Specific Addressing............13 70 5. Interaction Between The Optimizations..................15 72 6. IANA Considerations....................................16 74 7. Security Considerations................................17 75 7.1 Compact Format Security Considerations................17 76 7.2 Specific Addressing Security Considerations...........17 77 7.3 Results of Frame Misinterpretation....................17 79 8. References.............................................19 80 8.1 Normative References..................................19 81 8.2 Informative References................................20 83 Authors' Addresses........................................21 85 1. Introduction 87 TRILL switches (also called RBridges (Routing Bridges)) are devices 88 that support the IETF TRILL (TRansparent Interconnection of Lots of 89 Links) protocol [RFC6325] [RFC7177] [RFC7780]. They provide 90 transparent forwarding of frames in multi-hop networks with arbitrary 91 topology and link technology using least cost paths for unicast 92 traffic, support VLANs (Virtual Local Area Networks) and 24-bit Fine 93 Grained Labels [RFC7172], and support the multipathing of both 94 unicast and multi-destination traffic. They accomplish this by use of 95 a hop count and IS-IS (Intermediate System to Intermediate System) 96 link state routing [IS-IS] [RFC7176]. 98 A link between two TRILL switches in a TRILL campus can be any of a 99 variety of technologies, ranging from a complex bridged LAN to PPP 100 [RFC6361]. In the general case under the base TRILL protocol 101 [RFC6325], a TRILL Data frame consists of an inner payload formatted 102 as an Ethernet frame, preceded by a TRILL Header, and then 103 encapsulated by a link envelope appropriate for the link technology. 105 1.1 Structure of This Document 107 Section 2 discusses General Format TRILL Data frames without the 108 enhancements specified in this document. 110 In the case where the link is a point-to-point Ethernet link, an 111 optional Compact Format is specified for TRILL Data frames that saves 112 16 bytes. Section 3 specifies that format, its processing, and the 113 conditions for its safe use. 115 In the case where a multi-destination TRILL Data frame is being 116 forwarded over a multi-access link with multiple ports connected but 117 there is only one (or perhaps a few) next hop TRILL switches of 118 interest, optional Specific Addressing allows the TRILL Data frame to 119 be link unicast. This can substantially reduce the burden that frame 120 represents if, for example, the link is a complex bridged LAN through 121 which the frame might otherwise be flooded. Section 4 specifies the 122 Specific Addressing enhancement and the conditions for its safe use. 124 Section 5 discusses potential interaction between these two 125 enhancements. The remaining Sections after Section 5 provide IANA and 126 Security Considerations, References, and the like. 128 This document updates [RFC6325]. 130 1.2 Terminology Used in This Document 132 The terminology and acronyms defined in [RFC6325] are used herein 133 with the same meaning. In particular, the terms "campus", "native 134 frame", "link", etc., are as defined [RFC6325]. 136 "Point-to-point", as used herein, means a link which appears to be an 137 isolated channel between exactly two TRILL switch ports. Such a link 138 may not include customer bridges but may include hubs/repeaters, Two 139 Port MAC Relays, Provider Bridges, Provider Back Bone Bridges 140 [802.1Q], or other technology, provided that technology is configured 141 to provide a transparent point-to-point path between the end point 142 RBridge ports. 144 References herein to "VLAN Tag" or the like are to customer VLANs (C- 145 Tags, Ethertype 0x8100). Use of S-Tags, also known as Service Tags, 146 or stacked VLAN or other tags is beyond the scope of this document 147 but is an obvious extension. 149 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 150 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 151 document are to be interpreted as described in [RFC2119]. 153 2. TRILL Frame Formats 155 The subsections below provide a description of the general format of 156 TRILL Data frames. It then narrows in to describe the format of TRILL 157 Data frames on Ethernet links. 159 2.1 The General TRILL Frame Format 161 The general "on-the-wire" form of TRILL frames is illustrated below. 163 The Link Headers and Trailers in the formats below depend on the 164 specific link technology. The Link Header contains one or more fields 165 that distinguish TRILL Data from TRILL IS-IS. For example, over 166 Ethernet, the TRILL Data Link Header ends with the TRILL Ethertype 167 while the TRILL IS-IS frame Link Header ends with the L2-IS-IS 168 Ethertype; on the other hand, over PPP, there are no Ethertypes but 169 PPP protocol codes perform that function [RFC6361]. 171 A TRILL Data frame in transit between two neighboring RBridges is as 172 shown below: 174 +---------------+----------+----------------+---------------+ 175 | TRILL Data | TRILL | Payload | TRILL Data | 176 | Link Header | Header | Native Frame | Link Trailer | 177 +---------------+----------+----------------+---------------+ 179 Figure 1. Format of TRILL Data Frames 181 In the above diagram, the Payload Native Frame is in a restricted 182 Ethernet frame format with a VLAN or FGL [RFC7172] label but with no 183 trailing Frame Check Sequence (FCS). The payload frame format is 184 shown below, assuming the payload starts with an Ethertype (it might 185 alternatively be LLC [802-2014] encoded or some other format): 187 +-----------+------------+--------+-----------+------------ 188 | MAC Dest. | MAC Source | Label | Ethertype | ... 189 +-----------+------------+--------+-----------+------------ 191 Figure 2. Format of the Payload Frame 193 The encapsulated payload has the following fields in sequence: 195 o A 6-byte destination MAC address (Inner.MacDA) 197 o A 6-byte source MAC address (Inner.MacSA) 199 o An Inner.Label giving the VLAN ID or FGL [RFC7172], Priority, and 200 DEI (Drop Eligibility Indicator) [RFC7780] of the payload (use of 201 an S-tag or stacked tags is beyond the scope of this document but 202 is an obvious extension) 204 o The payload frame's content (which usually starts with an 205 Ethertype, such as the Ethertype for IPv4 or IPv6) 207 TRILL IS-IS frames are also sent between neighboring RBridges and 208 must be distinguished from TRILL Data frames. TRILL IS-IS frames are 209 formatted as follows and cannot use the Compact Format specified 210 herein: 212 +--------------+---------------+--------------+ 213 | TRILL IS-IS | TRILL IS-IS | TRILL IS-IS | 214 | Link Header | Payload | Link Trailer | 215 +--------------+---------------+--------------+ 217 Figure 3. TRILL IS-IS Frame 219 2.2 Ethernet Link TRILL Data Frame General Encapsulation 221 If the link between neighbor RBridges is Ethernet, then the general 222 TRILL Data frame format has the following link encapsulation: 224 Link Header: a 6-byte outer MAC destination address (Outer.MacDA) 225 followed by a 6-byte outer MAC source address (Outer.MacSA) 226 followed by an optional 4-byte outer VLAN tag Ethertype and 227 value (Outer.VLAN), and finally the 2-byte TRILL Ethertype 228 (0x22F3). Additional tags could be included after the outer MAC 229 addresses and before the TRILL Ethertype such a MACSEC 230 [802.1AE]. 232 Under the TRILL standard before this document, the Outer.MacDA 233 was required to be the unicast MAC address of the destination 234 RBridge port, if the TRILL Data frame was a unicast frame to a 235 known destination, and was required to be the All-RBridges 236 multicast address, if the TRILL Data frame was a multi- 237 destination frame. 239 +-----------+------------+- - - - - +-----------+ 240 | MAC Dest. | MAC Source | VLAN Tag | TRILL | 241 | Address | Address | if Req. | Ethertype | 242 +-----------+------------+ - - - - -+-----------+ 244 Figure 4. TRILL Data Link Header on an Ethernet Link 246 Link Trailer: the 32-bit IEEE [802.3] Frame Check Sequence (FCS). 248 In the General Format for Ethernet links, the Outer.VLAN can be 249 omitted when it is not required by VLAN sensitive equipment in the 250 link. 252 3. Compact Format for Point-to-Point Ethernet Links 254 TRILL Data frames may optionally be sent using a Compact Format that 255 compresses the headers involved if the link is a point-to-point 256 Ethernet link, Compact Format can be enabled by both RBridges on the 257 link if other conditions met as listed below. 259 The Compact Format is simple: the Outer.MacDA, Outer.MacSA, and 260 Outer.VLAN are replaced by the Inner.MacDA, Inner.MacSA, and Inner 261 Label and the Inner fields are deleted. This saves 6 + 6 + 4 or 16 262 bytes. To avoid confusion, Compact Format MUST NOT be used if the 263 Inner.MacDA is a multi-cast address assigned to TRILL 264 (01-80-C2-00-00-40 through 01-80-C2-00-00-4F). 266 Compact Format is not applicable to TRILL IS-IS frames because there 267 is no inner Ethernet header. (And, of course, Compact Format is not 268 applicable to native frames or Layer 2 Ethernet control frames since 269 those frames are not TRILL frames.) 271 +---------------------+--------+-----------+---------+---------+ 272 | Ethernet Header | TRILL | Content | Content | Link | 273 | Header from Payload | Header | Ethertype | ... | Trailer | 274 +---------------------+--------+-----------+---------+---------+ 276 Figure 5. Compact Format TRILL Data Frame 278 Compact Format is generally intended for use on point-to-point 279 Ethernet links between RBridges, a common arrangement in many LANs. 280 However, if there are any transparent devices in the apparent point- 281 to-point link, such as Provider Bridges or Provider Backbone Bridges, 282 then the use of the Compact Format will increase the MAC address 283 learning table stress on such Provider Bridges or Provider Edge Back 284 Bone bridges. 286 3.1 Conditions for Using Compact Format 288 Use of Compact Format is a hop-by-hop decision. In successive RBridge 289 to RBridge hops, a TRILL Data frame might be sent alternately in 290 Compact Format and General Format. 292 There are a number of conditions, listed below, for using Compact 293 Format TRILL Data frames. Most of these boil down to maximizing the 294 assurance that the RBridge-to-RBridge Ethernet link over which the 295 Compact Format TRILL Data frame is to be sent is really point-to- 296 point. Only the General Format for TRILL Data frames is safe to use 297 on an RBridge Ethernet port that is to a multi-access link even if 298 the ports between which it is being sent have been configured as 299 point-to-point ports. (See also the frame reception process 300 variations described in Section 3.3.1.) 302 o The RBridge Ethernet port over which Compact Format TRILL Data 303 frames are to be sent MUST be configured as an IS=IS point-to- 304 point port (see Section 4.9.1 of [RFC6325]). 306 o The RBridge port through which the Compact Format TRILL Data frame 307 is being transmitted MUST be configured to send VLAN/FGL tagged 308 frames. Otherwise the Data Label of the payload will be lost 309 (unless it just happens to be the default VLAN ID of the receiving 310 port). 312 o The RBridge port at the other end of the link MUST be announcing 313 that it supports the Compact Format. See Section 3.4. 315 o Receipt of a native frame indicates that the link is multi-access 316 and has end stations on it. These are frames that are not Layer 2 317 control frames (see Section 1.4 of [RFC6325]) and have neither an 318 Outer.MacDA in the block assigned to TRILL nor an outer payload 319 EtherType assigned to/for TRILL (currently the TRILL, L2-IS-IS, 320 and RBridge-Channel [RFC7178] EtherTypes). On receipt of such a 321 frame, the port MUST stop using Compact Format TRILL Data frames 322 for at least ten seconds, unless it is reset by management or 323 rebooted before that. 325 o The sending RBridge MUST have exactly one adjacency in the Report 326 state on the link and no other adjacencies in any state but Down 327 [RFC7177]. Thus, receipt of a TRILL IS-IS Hello frame, other than 328 one of the correct type (point-to-point or LAN) from the RBridge 329 believed to be at the other end of the link, indicates that the 330 link really isn't point-to-point or that the RBridge at the other 331 end of that link is mis-behaving. In either case, the RBridge 332 receiving such an unexpected Hello MUST stop using Compact Format 333 TRILL Data frames on that port for at least twice the holding time 334 in the unexpected Hello but not less than ten seconds, unless it 335 is reset by management or rebooted before that. This is a change 336 to [RFC6325] which states that an RBridge port configured as 337 point-to-point ignores LAN Hellos and such a port configured as 338 LAN ignores point-to-point Hellos. 340 o RBridge Ethernet ports are required to monitor ports for BPDUs 341 received (Section 4.9.3 [RFC6325]). On receipt of a customer 342 bridging BPDU at an RBridge port, the RBridge MUST stop using 343 Compact Format on that port and revert to sending General Format 344 TRILL Data frames for at least four times the Bridge Hello Time in 345 the BPDU, but not less than ten seconds, unless the port or 346 RBridge is reset by management or rebooted before that. 348 o It is RECOMMENDED that RBridge ports intending to use Compact 349 Format also use the Link Layer Discovery Protocol (LLDP) [802.1AB] 350 to provide additional assurance that the link is actually point- 351 to-point. For this use, LLDP should be run to the Nearest Customer 352 Bridge MAC address (01-80-C2-00-00-00). Receipt by an RBridge port 353 supporting LLDP of an LLDP message indicating the presence on the 354 link of a MAC Bridge, Layer 3 Router, or End Station indicates 355 that the link is not point-to-point and the RBridge MUST stop 356 using Compact Format on the port for at least twice the TTL in the 357 received LLDP frame but not less than ten second, unless the port 358 or RBridge is reset by management or rebooted before that. 360 3.2 RBridge Originated and Terminated Native Frames 362 There can be native frames originated by or intended for consumption 363 by an RBridge. Examples include SNMP over IP frames or RBridge 364 Channel frames [RFC7178]. In many cases, such internal sinks and 365 sources of native frames are treated as a virtual end-station 366 internally attached to the RBridge. Such frames are converted to 367 TRILL Data frames before being transmitted outside the originating 368 RBridge. 370 Because of the way that Compact Format TRILL Data frames are 371 recognized, particularly the change in [RFC6325], Section 4.6.2, 372 Point 3, made by Section 3.3.1 of this document, an RBridge MUST use 373 a MAC address different from the address of any of its ports as the 374 Inner.MacSA of frames it locally originates and as the Inner.MacDA it 375 expects to see in unicast TRILL Data frames that it receives and 376 decapsulates for locally processing. 378 3.3 Compact TRILL Data Reception and Transmission 380 If an RBridge's Ethernet port has Compact Format enabled, frame 381 reception and transmission are modified as described below. 383 Section 4.6 of the TRILL base protocol standard [RFC6325] provides a 384 specification of the processing of all possible types of received 385 frames. TRILL frames are any frame starting with the TRILL or L2-IS- 386 IS or RBridge-Channel Ethertype or that has an Outer.MacDA that is 387 any of the block of 16 multicast addresses assigned to TRILL 388 ([RFC6325] Section 7.2). 390 3.3.1 Compact TRILL Data Frame Reception 392 Section 4.6.2 of [RFC6325] specifies the processing of received TRILL 393 frames. A complete replacement for Section 4.6.2 of [RFC6325] that 394 supports Compact Format and incorporates the correction in Section 395 5.1.2 of [RFC7780] is provided in the quoted text below. 397 Even when Compact Format is enabled, the sender is not required to 398 compact all or any TRILL Data frames and a receiver MUST be prepared 399 for an arbitrary mix of Compact Format and General Format TRILL Data 400 frames arriving on a point-to-point link. 402 NOTE: All of the Section references in the quoted text below are 403 references to Sections in [RFC6325]. 405 "A TRILL frame either has the TRILL or L2-IS-IS Ethertype or has a 406 multicast Outer.MacDA allocated to TRILL (see Section 7.2). The 407 following tests are performed sequentially, and the first that 408 matches controls the handling of the frame:" 410 "By default a frame is classified as General Format." 412 "1. If the Ethertype is L2-IS-IS and the Outer.MacDA is either 413 All-IS-IS-RBridges or the unicast MAC address of the 414 receiving RBridge port, the frame is handled as described in 415 Section 4.6.2.1 on TRILL Control frames." 417 "2. If the Outer.MacDA is a multicast address allocated to TRILL 418 other than All-RBridges then the frame is discarded." 420 "3. If the Outer.MacDA is a unicast address other than the 421 address of the receiving Rbridge then (3a) if Compact Format 422 TRILL Data frames are disabled, the frame is discarded or 423 (3b) if Compact Format TRILL Data frames are enabled, the 424 frame is classified as compact." 426 "4. If the Ethertype is not TRILL, the frame is discarded." 428 "5. If the Version field in the TRILL Header is greater than 0, 429 the frame is discarded." 431 "6. If the hop count is 0, the frame is discarded." 433 "7. If the Outer.MacDA is multicast and the M bit is zero the 434 frame is discarded. If the Outer.MacDA is unicast and M bit 435 is one processing continues if Specific Addressing is 436 enabled. If Specific Addressing is not enabled, the frame is 437 discarded." 439 "8. If the frame has been classified as Compact Format, skip the 440 rest of this rule and go to Rule 9. By default, an RBridge 441 MUST discard General Format TRILL Data frames from a 442 Outer.MacSA that is not an adjacency on the port where the 443 frame was received. RBridges MAY be configured per port to 444 accept such frames in cases where it is known that a non- 445 peering device (such as an end-station) is configured to 446 originate general TRILL encapsulated data frames that can be 447 safely accepted." 449 "9. If a frame has been classified as a Compact Format TRILL Data 450 frame but it was received untagged, that is, without an 451 Outer.VLAN, discard the frame." 453 "10. For all subsequent processing, including Rule 11, if the 454 frame has been classified as Compact Format, all references 455 to Inner.MacDA, Inner.MacSA, or Inner.VLAN are to be 456 understood to actually refer to the Outer.MacDA, Outer.MacSA, 457 and Outer.VLAN as the frame was received." 459 "11. The Inner.MacDA is then tested. If it is the All-Egress- 460 Rbridges (also known as All-ESADI-RBridges) multicast address 461 and RBn implements the ESADI protocol, processing proceeds as 462 in Section 4.6.2.2 for TRILL ESADI frames. If it is any other 463 address or RBn does not implement ESADI, processing proceeds 464 as in Section 4.6.2.3 for TRILL Data frames." 466 3.3.2 Compact TRILL Data Frame Transmission 468 When a TRILL Data frame is being transmitted out an RBridge port, if 469 the conditions listed in Section 3 above are met, the frame MAY be 470 sent in Compact Format. 472 3.4 Announcing Support for Compact Format 474 The Compact Format option is a hop-by-hop optional Ethernet link 475 TRILL frame format and it is possible that an RBridge would support 476 it on some ports and not others depending, for example, on port 477 hardware. Therefore, if Compact Format is enabled at a port, this is 478 indicated in every Hello (Section 6) it sends out that port. 480 4. Specific Addressing 482 Specific addressing optionally enables more efficient use of some 483 types of multi-access links. 485 4.1 Current Multi-Destination Addressing 487 When multiple RBridges are connected to an Ethernet link, the base 488 TRILL protocol standard [RFC6325] requires that multi-destination 489 TRILL Data frames be sent on the Ethernet link addressed to the All- 490 RBridges multicast address. 492 If the link is a multi-access link, such as a large bridged LAN, use 493 of a multicast address may impose a significant burden, causing the 494 frame to be flooded in the bridged LAN. In addition, all or many 495 stations attached to the bridged LAN may received the frame using up 496 some of their input bandwidth. Those TRILL switches that receive the 497 frame but are not the next hop on the frame's distribution tree will 498 discard the frame due to the Reverse Path Forwarding Check. 500 4.2 Specific Addressing Specification 502 Multi-destination TRILL Data frames are sent on the distribution tree 503 identified in the TRILL Header subject to optional pruning. The 504 transmitting RBridge thus knows which next hop RBridge or RBridges on 505 the link it needs to get the frame to. 507 If the next hop RBridges on the multi-access link and the 508 transmitting RBridge all have Specific Addressing enabled, then the 509 frame MAY be link unicast to the next hop RBridge or RBridges. 511 Use of Specific Addressing is a hop-by-hop optional decision. 512 Successive TRILL Data frames received by an RBridge, even from the 513 same sending RBridge on the same distribution tree, may be 514 specifically (unicast) or multicast addressed. (The same frame is 515 never sent both ways.) In successive RBridge to RBridge hops, a 516 multi-destination TRILL Data frame might be sent alternately in 517 specifically addressed and multicast addressed form. 519 4.3 Announcing Support for Specific Addressing 521 The Specific Addressing option is a hop-by-hop optional format. It is 522 possible that an RBridge would support it on some ports and not 523 others. Therefore enablement of this option is indicated in every 524 TRILL Hello (see Section 6) sent on the port. 526 5. Interaction Between The Optimizations 528 Compact Format can only be used for TRILL Data frames on Ethernet 529 links that are point-to-point. Compact Format works under the 530 conditions specified above regardless of whether the frame is TRILL 531 unicast (M=0) or TRILL multi-destination (M=1). It sets the 532 Outer.MacDA, Outer.MacSA, and Outer.VLAN to the corresponding Inner 533 fields and removes the Inner fields. 535 Specific Addressing is only beneficial for frames that are TRILL 536 multi-destination Data frames on multi-access links. Specific 537 Addressing causes the frame to be link unicast by setting the 538 Outer.MacDA to the unicast address of a next hop RBridge. 540 Both optimizations change the Outer.MacDA from its value in the base 541 TRILL protocol and thus they conflict. Specific Addressing MUST NOT 542 be used on point-to-point Ethernet links. This avoids conflict. 544 6. IANA Considerations 546 IANA is requested to allocate two capability bits in the TRILL-PORT- 547 VER sub-TLV [RFC7176] as follows: 549 Bit Description Reference 550 ====== ============================== ================= 551 tbd1 Compact Ethernet enabled. (This document) 552 tbd2 Specific addressing enabled. (This document) 554 7. Security Considerations 556 For general TRILL protocol security considerations, see [RFC6325]. 557 See other security considerations below. 559 7.1 Compact Format Security Considerations 561 An RBridge conformant to the TRILL standard that has Compact Format 562 TRILL Data not implemented or not enabled on a port will, as part of 563 its normal procedures, discard any Compact Format TRILL Data frame it 564 receives on that port because the EtherType of the frame would be 565 TRILL but (1) if the Compact Format resulted in a unicast 566 Outer.MacDA, it would not be the address of the receiving RBridge 567 port, and (2) if the Compact Format resulted in a multicast or 568 broadcast Outer.MacDA, it would not be the All-RBridges multicast 569 address. If the RBridge port failed to discard the frame and 570 erroneously handled it as being in General Format, bad things will 571 usually happen as described in Section 7.3. 573 With a General Format TRILL Data frame, the Data Label of the data is 574 somewhat protected in the Inner Label field. With Compact Format, it 575 is put in the more exposed Outer.VLAN field. If it is stripped, 576 perhaps by an intervening bridge, and the frame arrives untagged, the 577 rules in this document require that it be discarded to avoid changing 578 the labeling of the frame to the default of the receiving RBridge 579 port. 581 7.2 Specific Addressing Security Considerations 583 It is important not to apply both Compact Format optimization and 584 Specific Addressing optimization to the same frame or else the frame 585 may be misinterpreted as described in Section 7.3. For this reasons, 586 use of Specific Addressing on point-to-point links, where it would 587 not provide an advantage anyway, is prohibited. 589 7.3 Results of Frame Misinterpretation 591 For frames that are misinterpreted due to circumstances described in 592 Sections 7.1 and 7.2, the first six bytes of the native frame content 593 will be treated as the Inner.MacDA, the next six bytes of that oontnt 594 as the Inner.MacSA, and the next four bytes as the Data Label. If the 595 Ethertype or the Data Label is not checked or some of the payload 596 data accidentally has the value of a valid tag Ethertype, the payload 597 may be delivered in the wrong VLAN violating security policy. For 598 this reason, the provisions of Sections 3 of this document should be 599 scrupulously enforced. 601 8. References 603 Normative and informative references for this document are given 604 below. 606 8.1 Normative References 608 [802.1AB] - IEEE, "IEEE Standard for Local and metropolitan area 609 networks / Station and Media Access Control Connectivity 610 Discovery", IEEE Std 802.1AB-2009, 17 September 2009. 612 [802.1Q] - IEEE, "IEEE Standard for Local and metropolitan area 613 networks / Virtual Bridged Local Area Networks", IEEE Std 614 802.1Q-2011, May 2011. 616 [IS-IS] - ISO/IEC 10589:2002, Second Edition, "Intermediate System to 617 Intermediate System Intra-Domain Routing Exchange Protocol for 618 use in Conjunction with the Protocol for Providing the 619 Connectionless-mode Network Service (ISO 8473)", 2002. 621 [RFC2119] - Bradner, S., "Key words for use in RFCs to Indicate 622 Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, 623 March 1997, . 625 [RFC6325] - Perlman, R., Eastlake 3rd, D., Dutt, D., Gai, S., and A. 626 Ghanwani, "Routing Bridges (RBridges): Base Protocol 627 Specification", RFC 6325, DOI 10.17487/RFC6325, July 2011, 628 . 630 [RFC7172] - Eastlake 3rd, D., Zhang, M., Agarwal, P., Perlman, R., 631 and D. Dutt, "Transparent Interconnection of Lots of Links 632 (TRILL): Fine-Grained Labeling", RFC 7172, DOI 633 10.17487/RFC7172, May 2014, . 636 [RFC7176] - Eastlake 3rd, D., Senevirathne, T., Ghanwani, A., Dutt, 637 D., and A. Banerjee, "Transparent Interconnection of Lots of 638 Links (TRILL) Use of IS-IS", RFC 7176, DOI 10.17487/RFC7176, 639 May 2014, . 641 [RFC7780] - Eastlake 3rd, D., Zhang, M., Perlman, R., Banerjee, A., 642 Ghanwani, A., and S. Gupta, "Transparent Interconnection of 643 Lots of Links (TRILL): Clarifications, Corrections, and 644 Updates", RFC 7780, DOI 10.17487/RFC7780, February 2016, 645 . 647 8.2 Informative References 649 [802-2014] - IEEE 802, "IEEE Standard for Local and Metropolitan Area 650 Networks / Overview and Architecture", 802-2014, 12 June 2014. 652 [802.1AE] - IEEE 802, "IEEE Standard for Local and metropolitan area 653 networks / Media Access Control (MAC) Security", 802.1AE-2006, 654 18 August 2006. 656 [802.3] - IEEE, "IEEE Standard for Information technology / 657 Telecommunications and information exchange between systems / 658 Local and metropolitan area networks / Specific requirements 659 Part 3: Carrier sense multiple access with collision detection 660 (CSMA/CD) access method and physical layer specifications", 661 IEEE Std 802.3-2012, 28 December 2012. 663 [RFC6361] - Carlson, J. and D. Eastlake 3rd, "PPP Transparent 664 Interconnection of Lots of Links (TRILL) Protocol Control 665 Protocol", RFC 6361, August 2011. 667 [RFC7177] - Eastlake 3rd, D., Perlman, R., Ghanwani, A., Yang, H., 668 and V. Manral, "Transparent Interconnection of Lots of Links 669 (TRILL): Adjacency", RFC 7177, DOI 10.17487/RFC7177, May 2014, 670 . 672 [RFC7178] - Eastlake 3rd, D., Manral, V., Li, Y., Aldrin, S., and D. 673 Ward, "Transparent Interconnection of Lots of Links (TRILL): 674 RBridge Channel Support", RFC 7178, DOI 10.17487/RFC7178, May 675 2014, . 677 Authors' Addresses 679 Radia Perlman 680 EMC 681 2010 256th Avenue NE, #200 682 Bellevue, WA 98007 USA 684 EMail: radia@alum.mit.edu 686 Donald E. Eastlake 3rd 687 Huawei Technologies 688 155 Beaver Street 689 Milford, MA 01757, USA 691 Phone: +1-508-333-2270 692 Email: d3e3e3@gmail.com 694 Yizhou Li 695 Huawei Technologies 696 101 Software Avenue, 697 Nanjing 210012, China 699 Phone: +86-25-56622310 700 Email: liyizhou@huawei.com 702 Anoop Ghanwani 703 Dell 704 350 Holger Way 705 San Jose, CA 95134 USA 707 Phone: +1-408-571-3500 708 Email: anoop@alumni.duke.edu 710 Copyright and IPR Provisions 712 Copyright (c) 2016 IETF Trust and the persons identified as the 713 document authors. All rights reserved. 715 This document is subject to BCP 78 and the IETF Trust's Legal 716 Provisions Relating to IETF Documents 717 (http://trustee.ietf.org/license-info) in effect on the date of 718 publication of this document. Please review these documents 719 carefully, as they describe your rights and restrictions with respect 720 to this document. Code Components extracted from this document must 721 include Simplified BSD License text as described in Section 4.e of 722 the Trust Legal Provisions and are provided without warranty as 723 described in the Simplified BSD License. The definitive version of 724 an IETF Document is that published by, or under the auspices of, the 725 IETF. Versions of IETF Documents that are published by third parties, 726 including those that are translated into other languages, should not 727 be considered to be definitive versions of IETF Documents. The 728 definitive version of these Legal Provisions is that published by, or 729 under the auspices of, the IETF. Versions of these Legal Provisions 730 that are published by third parties, including those that are 731 translated into other languages, should not be considered to be 732 definitive versions of these Legal Provisions. For the avoidance of 733 doubt, each Contributor to the IETF Standards Process licenses each 734 Contribution that he or she makes as part of the IETF Standards 735 Process to the IETF Trust pursuant to the provisions of RFC 5378. No 736 language to the contrary, or terms, conditions or rights that differ 737 from or are inconsistent with the rights and licenses granted under 738 RFC 5378, shall have any effect and shall be null and void, whether 739 published or posted by such Contributor, or included with or in such 740 Contribution.