TRILL Working Group Weiguo Hao INTERNET-DRAFT Donald Eastlake Intended status: Proposed Standard Yizhou Li Huawei Expires: November 23, 2015 May 24, 2016 TRILL: Address Flush Message Abstract The TRILL (TRansparent Interconnection of Lots of Links) protocol, by default, learns end station addresses from observing the data plane. This document specifies a message by which an originating TRILL switch can explicitly request other TRILL switches to flush certain MAC reachability learned through the egress of TRILL Data packets. This is a supplement to the TRILL automatic address forgetting and can assist in achieving more rapid convergence in case of topoogy or configuration change. Status of This Memo This Internet-Draft is submitted to IETF in full conformance with the provisions of BCP 78 and BCP 79. Distribution of this document is unlimited. Comments should be sent to the TRILL working group mailing list: trill@ietf.org. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet- Drafts. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." The list of current Internet-Drafts can be accessed at http://www.ietf.org/1id-abstracts.html. The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. W. Hao, et al. [Page 1] INTERNET-DRAFT Address Flush Message Table of Contents 1. Introduction............................................3 1.1 Terminology and Acronyms...............................3 2. Address Flush Message Details...........................5 2.1 VLAN Block Case........................................6 2.2 Extensible Case........................................7 3. IANA Considerations....................................11 4. Security Considerations................................11 Normative References......................................12 Informative References....................................12 Acknowledgements..........................................12 Authors' Addresses........................................13 W. Hao, et al. [Page 2] INTERNET-DRAFT Address Flush Message 1. Introduction Edge TRILL (Transparent Interconnection of Lots of Links) switches [RFC6325] [RFC7780], also called edge RBridges, by default learn end station MAC address reachability from observing the data plane. On receipt of a native frame from an end station, they would learn the local MAC address attachment of the source end station. And on egressing (decapsulating) a remotely originated TRILL Data packet, they learn the remote MAC address and remote attachment TRILL switch. Such learning is all scoped by data label (VLAN or Fine Grained Label [RFC7172]). TRILL has mechanisms for timing out such learning and appropriately clearing it based on some network connectivity and configuration changes; however, there are circumstances under which it would be helpful for a TRILL switch to be able to explicitly flush (purge) certain learned end station reachability information in remote RBridges to achieve more rapid convergence (see, for example, [TCaware] and Section 6.2 of [RFC4762]). A TRILL switch R1 can easily flush any locally learned addresses it wants. This document specifies an RBridge Channel protocol [RFC7178] message to request flushing address information learned from decapsulating at remote RBridges. 1.1 Terminology and Acronyms The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in [RFC2119]. This document uses the terms and acronyms defined in [RFC6325] and [ChannelTunnel] as well as the following: Data Label - VLAN or FGL. Edge TRILL switch - A TRILL switch attached to one or more links that provide end station service. FGL - Fine Grained Label [RFC7172]. Management VLAN - A VLAN in which all TRILL switches in a campus indicate interest so that multi-destinaiton TRILL Data packets, including RBridge Channel messages [ChannelTunnel], sent with that VLAN as the Inner.VLAN will be delivered to all TRILL switches in the campus. Usually no end station service is offered in the Management VLAN. W. Hao, et al. [Page 3] INTERNET-DRAFT Address Flush Message RBridge - A alterntive name for a TRILL switch. TRILL switch - A device implementing the TRILL protocol. W. Hao, et al. [Page 4] INTERNET-DRAFT Address Flush Message 2. Address Flush Message Details The Address Flush message is an RBridge Channel protocol message [RFC7178]. The general structure of an RBridge Channel packet on a link between TRILL switches is shown in Figure 1 below. The type of RBridge Channel packet is given by the Protocol field in the RBridge Channel Header that indicates how to interpret the Channel Protocol Specific Payload [RFC7178]. +----------------------------------+ | Link Header | +----------------------------------+ | TRILL Header | +----------------------------------+ | Inner Ethernet Addresses | +----------------------------------+ | Data Label (VLAN or FGL) | +----------------------------------+ | RBridge Channel Header | +----------------------------------+ | Channel Protocol Specific Payload| +----------------------------------+ | Link Trailer (FCS if Ethernet)| +----------------------------------+ Figure 1. RBridge Channel Protocol Message Structure An Address Flush RBridge Channel message by default applies to addresses within the Data Label in the TRILL Header. Address Flush protocol messages are usually sent as multi-destination packets (TRILL Header M bit equal to one) so as to reach all TRILL switches offering end station service in the VLAN or FGL specified by the Data Label. Such messages SHOULD be sent at priority 6 since they are important control messages but lower priority than control messages that establish or maintain adjacency. Nevertheless: - There are provisions for optionally indicating the Data Label(s) to be flushed for cases where the Address Flush message is sent over a Managagement VLAN or the like. - An Address Flush message can be sent unicast, if it is desired to clear addresses at one TRILL switch only. W. Hao, et al. [Page 5] INTERNET-DRAFT Address Flush Message 2.1 VLAN Block Case Figure 2 below expands the RBridge Channel Header and Channel Protocol Specific Payload from Figure 1 for the case of the VLAN based Address Flush message. This form of the Address Flush message is optimized for flushing MAC addressed based on nickname and blocks of VLANs. 0 1 2 3 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 RBridge Channel Header: +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | RBridge-Channel (0x8946) | 0x0 | Channel Protocol = TBD | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Flags | ERR | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Address Flush Protocol Specific: +-+-+-+-+-+-+-+-+ | K-nicks | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Nickname 1 | Nickname 2 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Nickname ... | Nickname K-nicks | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | K-VBs | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | RESV | Start.VLAN 1 | RESV | End.VLAN 1 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | RESV | Start.VLAN 2 | RESV | End.VLAN 2 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | RESV | Start.VLAN ... | RESV | End.VLAN ... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | RESV | Start.VLAN K-VBs | RESV | End.VLAN K-VBs | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 2. Address Flush Message - VLAN Case The fields in Figure 2 related to the Address Flush message are as follows: Channel Protocol: The RBridge Channel Protocol value allocated for Address Flush (see Section 3). K-nicks: K-nicks is the number of nicknames present as an unsigned integer. If this is zero, the ingress nickname in the TRILL Header is considerted to be the only nickname to which the message applies. If non-zero, it given the number of nicknames present to which the message applies. The messages flushes address learning due to egressing TRILL Data packets that had a ingress nicknam to which the message applies. W. Hao, et al. [Page 6] INTERNET-DRAFT Address Flush Message Nickname: A listed nickname to which it is intended that the Address Flush message apply. If an unknown or reserved nickname occurs in the list, it is ignored but the address flush operation is still executed with the other nicknames. If an incorrect nickname occurs in the list, so some address learning is flushed that should not have been flush, the network will strill operate correctly but will be less efficient as the incorrectly flushed learning is re-learned. K-VBs: K-VBs is the number of VLAN blocks present as an unsigned integer. If this byte is zero, the message is the more general format specified in Section 2.2. If it is non-zero, it gives the number of blocks of VLANs present. RESV: 4 reserved bits. MUST be sent as zero and ignored on receipt. Start.VLAN, End.VLAN: These 12-bit fields give the beginning and ending VLAN IDs of a block of VLANs. The block includes both the starting and endiing values so a block of size one is indicated by setting End.VLAN equal to Start.VLAN. If Start.VLAN is 0x000, it is treated as if it was 0x001. If End.VLAN is 0xFFF, it is treated as if it was 0xFFE. If End.VLAN is smaller than Start.VLAN, considering both as unsigned integers, that VLAN block is ignored but the address flush operation is still executed with any other VLAN blocks in the message. This message flushes all addresses learned from egressing TRILL Data packets with an applicable nickname and a VLAN in any of the blocks given. To flush addresses for all VLANs, it is easy to specify a block covering all valid VLAN IDs, this is, from 0x001 to 0xFFE. 2.2 Extensible Case A more general form of the Address Flush message is provided to support flushing by FGL and more efficient encodings of VLANs and FGLs where using a set of contiguous blocks if cumbersome. This form is also extensible to handle future requirements. It is indicated by a zero in the byte shown in Figure 2 as "K-VBs". W. Hao, et al. [Page 7] INTERNET-DRAFT Address Flush Message 0 1 2 3 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 RBridge Channel Header: +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | RBridge-Channel (0x8946) | 0x0 | Channel Protocol = TBD | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Flags | ERR | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Address Flush Protocol Specific: +-+-+-+-+-+-+-+-+ | K-nicks | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Nickname 1 | Nickname 2 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Nickname ... | Nickname K-nicks | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 0 | Type | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type Dependent Information +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-... Figure 3. Address Flush Message - Extensible Case Channel Protocol, K-nicks, Nickname: These fields are as specified in Section 2.1. Type: If the byte immediately before the Type field, which is the byte labeled "K-VBs" in Figure 2, is zero, the the Type byte indicates the type of extended Address Flush message as follows: Type Description ------ ------------ 0 Reserved 1 Bit Map of VLANs 2 Blocks of FGLs 3 List of FGLs 4 Bit Map of FGLs 5-254 Unassigned 255 Reserved Length: The length of the remaining information in the Address Flush message. Type Dependent Information: Depends on the value of the type field as further specified below in this section. W. Hao, et al. [Page 8] INTERNET-DRAFT Address Flush Message Type 1 Bit Map of VLANs: The Type Dependent Information consists of two bytes with the 12-bit starting VLAN ID N right justified (the top 4 bits are as specified above for RESV). This is followed by bytes with one bit per VLAN ID. The high order bit of the first byte is for VLAN N, the next to the highest order bit is for VLAN N+1, the low order bit of the first byte is for VLAN N+7, the high order bit of the second byte, if there is a second byte, is for VLAN N+8, and so on. If that bit is a one, the the Address Flush message applies to that VLAN. If that bit is a zero, then addresses that have been learned in that VLAN are not flushed. Note that Length MUST be at least 3. If Length is 0, 1, or 2 for a Type 1 extended Address Flush message, the message is corrupt and MUST be discarded. VLAN IDs do not wrap around. If there are enough bytes so that some bits correspond to VLAN ID 0xFFF or nigher, those bits are ignored but the message is still processed for bits corresponding to valid VLAN IDs. Type 2 Blocks of FGLs: The Type Dependent Information consists of sets of Start.FGL and End.FGL numbers. The Address Flush information applies to the FGLs in that range, incluse. A single FGL is indicated by have both Start.FGL and End.FGL to the same value. If End.FGL is less than Start.FGL, considering them as unsigned integers, that block is ignored but the Address Flush message is still processed for any other blocks present. For this Type, Length MUST be a multiple of 6; if it is not, the message is considered corrup and MUST be discarded. Type 3 List of FGLs: The Type Dependent Information consists of FGL numbers each in 3 bytes. The Address Flush message applies to those FGLs. For this Type, Length MUST be a multiple of 3; if it is not, the message is considered corrup and MUST be discarded. Type 4 Bit Map of FGLs: The Type Dependent Information consists of three bytes with the 24-bit starting FGL N. This is followed by bytes with one bit per FGL. The high order bit of the first byte is for FGL N, the next to the highest order bit is for FGL N+1, the low order bit of the first byte is for FGL N+7, the high order bit of the second byte, if there is a second byte, is for FGL N+8, and so on. If that bit is a one, the the Address Flush message applies to that FGL. If that bit is a zero, then addresses that have been learned in that FGL are not flushed. Note that Length MUST be at least 4. If Length is 0, 1, 2, or 3 for a Type 1 extended Address Flush message, the message is corrupt and MUST be discarded. FGLs do not wrap around. If there are enough bytes so that some bits correspond to an FGL higher than 0xFFFFFF, those bits are ignored but the message is still processed for bits corresponding to valid W. Hao, et al. [Page 9] INTERNET-DRAFT Address Flush Message FGLs. There is no provision for a list of VLAN IDs as there are few enough of them that an arbitrary subset of VLAN IDs can always be represented as a bit map. W. Hao, et al. [Page 10] INTERNET-DRAFT Address Flush Message 3. IANA Considerations IANA is requested to assign TBD as the Address Flush RBridge Channel Protocol number from the range of RBridge Channel protocols allocated by Standards Action [RFC7178]. The added RBridge Channel protocols registry entry on the TRILL Parameters web page is as follows: Protocol Description Reference -------- -------------- ------------------ TBD Address Flush [this document] 4. Security Considerations The Address Flush RBridge Channel Protocol provides no security assurances or features. However, use of the Address Flush protocol can be nested inside the RBridge Channel Tunnel Protocol [ChannelTunnel] using the RBridge Channel message payload type. The Channel Tunnel protocol can provide security services. See [RFC7178] for general RBridge Channel Security Considerations. See [RFC6325] for general TRILL Security Considerations. W. Hao, et al. [Page 11] INTERNET-DRAFT Address Flush Message Normative References [RFC2119] - Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC6325] - Perlman, R., D. Eastlake, D. Dutt, S. Gai, and A. Ghanwani, "RBridges: Base Protocol Specification", RFC 6325, July 2011. [RFC7172] - Eastlake 3rd, D., Zhang, M., Agarwal, P., Perlman, R., and D. Dutt, "Transparent Interconnection of Lots of Links (TRILL): Fine-Grained Labeling", RFC 7172, DOI 10.17487/RFC7172, May 2014, . [RFC7178] - Eastlake 3rd, D., Manral, V., Li, Y., Aldrin, S., and D. Ward, "Transparent Interconnection of Lots of Links (TRILL): RBridge Channel Support", RFC 7178, DOI 10.17487/RFC7178, May 2014, . [RFC7780] - Eastlake 3rd, D., Zhang, M., Perlman, R., Banerjee, A., Ghanwani, A., and S. Gupta, "Transparent Interconnection of Lots of Links (TRILL): Clarifications, Corrections, and Updates", RFC 7780, DOI 10.17487/RFC7780, February 2016, . Informative References [RFC4762] - Lasserre, M., Ed., and V. Kompella, Ed., "Virtual Private LAN Service (VPLS) Using Label Distribution Protocol (LDP) Signaling", RFC 4762, January 2007. [ChannelTunnel] - Eastlake, D., M. Umair, Y. Li, "TRILL: RBridge Channel Tunnel Protocol", draft-ietf-trill-channel-tunnel, work in progress. [TCaware] - Y. Li, et al., "Aware Spanning Tree Topology Change on RBridges" draft-yizhou-trill-tc-awareness, work-in-progress. Acknowledgements The document was prepared in raw nroff. All macros used were defined within the source file. W. Hao, et al. [Page 12] INTERNET-DRAFT Address Flush Message Authors' Addresses Weiguo Hao Huawei Technologies 101 Software Avenue, Nanjing 210012, China Phone: +86-25-56623144 Email: haoweiguo@huawei.com Donald E. Eastlake, 3rd Huawei Technologies 155 Beaver Street Milford, MA 01757 USA Phone: +1-508-333-2270 EMail: d3e3e3@gmail.com Yizhou Li Huawei Technologies 101 Software Avenue, Nanjing 210012 China Phone: +86-25-56624629 Email: liyizhou@huawei.com W. Hao, et al. [Page 13] INTERNET-DRAFT Address Flush Message Copyright, Disclaimer, and Additional IPR Provisions Copyright (c) 2016 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (http://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. 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No language to the contrary, or terms, conditions or rights that differ from or are inconsistent with the rights and licenses granted under RFC 5378, shall have any effect and shall be null and void, whether published or posted by such Contributor, or included with or in such Contribution. W. Hao, et al. [Page 14]