TRILL Working Group Radia Perlman INTERNET-DRAFT Sun Microsystems Intended status: Proposed Standard Dinesh Dutt Cisco Systems Donald Eastlake 3rd Stellar Switches Expires: June 3, 2010 December 4, 2009 RBridge VLAN Mapping Status of This Document 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. 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 Abstract Some bridge products perform a feature known as "VLAN mapping" or "VLAN ID translation", in which a bridge translates a data frame's VLAN ID from one VLAN to another when it forwards a frame from one port to another. This feature facilitates scenarios such as combining two bridged LANs with overlapping VLAN IDs into one bridged LAN without merging two communities just because they have been given the same VLAN ID in the original two clouds. This document describes how RBridges can achieve the same functionality. R. Perlman, et al. [Page 1] INTERNET-DRAFT RBridge VLAN Mapping Table of Contents Status of This Document....................................1 Abstract...................................................1 1. Introduction............................................3 1.1 Terminology............................................4 2. Internal RBridges and VLAN Mapping......................5 3. Configuration of Cut Set VLAN Mapping RBridges..........5 4. Advertisement of VLAN Mappings..........................6 5. Translation of VLAN IDs by Cut Set RBridges.............6 6. Reporting Attached VLANs by Cut Set RBridges in LSPs....6 7. Advertising of Multicast Groups by Cut Set RBridges.....7 8. Endnode Advertisements by cut set RBridges..............7 9. IANA Considerations.....................................8 10. Security Considerations................................8 11. Normative References...................................9 12. Informative References.................................9 Appendix Z: Change Summary................................10 Authors' Addresses........................................11 Copyright, Disclaimer, and Additional IPR Provisions......12 R. Perlman, et al. [Page 2] INTERNET-DRAFT RBridge VLAN Mapping 1. Introduction Bridges perform a feature known as "VLAN mapping" or "VLAN ID translation", in which two or more layer 2 clouds are connected together using a set of bridges, but in which the VLAN IDs are not consistent in the different clouds. The set of bridges interconnecting the clouds are known as the "cut set", meaning that if that set of bridges is removed, the clouds are separated. Bridges in the cut set are configured to translate some set of VLAN IDs in one cloud to different VLAN IDs when forwarding from one cloud to the other. One reason to do this is to intentionally not merge VLAN-A endnodes in one layer 2 cloud with the community of VLAN-A endnodes in the other cloud. Another reason to do this is to intentionally merge two communities, marked with different VLAN IDs in the different clouds. This feature is accomplished solely by configuring bridges in the cut set. This document explains how to accomplish the same functionality with RBridges. In this document we will assume there are two clouds "East" and "West", and RBridges RB1, RB2, and RB3 that interconnect the two clouds. . . . +-----+ . . . . . . + - - - - + RB1 + - - - - + . . . . W . +-----+ . . E . . e . . . a . . s . +-----+ . s . . . t . .+ - - - - -+ RB2 + - - - - - - +. t . . . . -+-+---+ . . . . C . . / | _ _ _ _ _ _+. C . . l . + - - - | / . l . . . o . . +-+---+ . o . . u . .+ - - - -+ RB3 + - - - - - - - +. u . . . d . . +-----+ d . . . . . . . . . We will refer to RBridges other than the cut set of RBridges as "internal RBridges". General familiarity with the base TRILL protocol [RFCtrill] is assumed in this document. R. Perlman, et al. [Page 3] INTERNET-DRAFT RBridge VLAN Mapping 1.1 Terminology The same terminology and acronyms are used in this document as in [RFCtrill]. 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]. R. Perlman, et al. [Page 4] INTERNET-DRAFT RBridge VLAN Mapping 2. Internal RBridges and VLAN Mapping Internal RBridges will not be aware that VLAN mapping is going on. They will behave exactly as they would without VLAN mapping. The only evidence they will have of VLAN mapping is the existence of an optional TLV field that a cut set RBridge, RB1, MAY include in its LSP, listing the VLAN mappings that RB1 is configured to be performing. Internal RBridges will ignore this TLV field. It is only there for detection of misconfiguration. 3. Configuration of Cut Set VLAN Mapping RBridges If VLAN A in cloud "East" is to be translated into VLAN B in cloud "West", a cut set RBridge RB1 MUST be configured, for every port, as to whether that port is in East or West, and configured with VLAN mappings, such as: "East/VLAN A <----> West/VLAN B" That mapping means that when RB1 forwards a frame on a port configured to be in East to a port configured to be in West, with the VLAN tag of A, it replaces the VLAN tag "A" with "B" in the inner encapsulated frame. Note that mappings are always symmetric, meaning that if RB1 is translating tag "VLAN A" to tag "VLAN B" when forwarding from East to West, it will translate tag "VLAN B" to tag "VLAN A" when forwarding from West to East. The complete rules for a cut set RBridge forwarding a frame from port X in VLAN A to port Y are as follows: 1. If the ports connect to the same cloud, the frame is forwarded without VLAN translation. 2. If the ports connect to different clouds then 2.a If there is a translation in effect for VLAN A frames arriving from the cloud to which port X connects, the VLAN ID is changed according to the translation. 2.b If there is no translation in effect for VLAN A frames arriving from the cloud to which port X connects but there is a translation from some other VLAN arriving a port X into VLAN A when sent out port Y, then the frame is not forwarded out port Y. R. Perlman, et al. [Page 5] INTERNET-DRAFT RBridge VLAN Mapping 2.c If neither 2.a nor 2.b applies, the frame is forwarded without VLAN translation. 4. Advertisement of VLAN Mappings To detect misconfiguration, a cut set RBridge RB1 MAY advertise its VLAN mappings. This is done by assigning 16-bit IDs to each of the clouds by manual configuration. All cut set RBridges SHOULD be configured with the same IDs for the clouds. So, in our example, if "East" is "1" and "West" is "2", and VLAN A in East is mapped to VLAN B in West, the TLV would report a set of mappings, including: {(1:A,2:B)} 5. Translation of VLAN IDs by Cut Set RBridges If RB1 is configured to believe port X is in "East" and port Y is in "West", and RB1 is configured such that "East/VLAN A <----> West/VLAN B", then when RB1 forwards data frames from port X to port Y, if the received frame from port X has (inner header VLAN ID) VLAN A , then RB1 changes the VLAN tag from VLAN A to VLAN B as it forwards onto port Y. Note: This is true whether RB1 is the appointed forwarder on port X for VLAN A and the frame arrives unencapsulated, or whether the frame has arrived already encapsulated as a VLAN A frame. Likewise, RB1 performs the same VLAN translation whether the frame is unicast or multicast. 6. Reporting Attached VLANs by Cut Set RBridges in LSPs If RB1 is configured to translate VLAN A to VLAN B, then RB1 reports, in its LSP, that it is connected to both VLAN A and VLAN B, even if RB1 is not appointed forwarder for either or both VLAN A or VLAN B. The reason RB1 must claim to be attached to VLAN A and VLAN B is so that multi-destination data frames for VLAN A originating in West will not get filtered before reaching RB1, and multi-destination data frames for VLAN B originating in East will also not get prematurely filtered. R. Perlman, et al. [Page 6] INTERNET-DRAFT RBridge VLAN Mapping 7. Advertising of Multicast Groups by Cut Set RBridges If RB1 is configured to translate VLAN A in East to VLAN B in West, then RB1 MUST take steps as described below in order to ensure that a multicast packet for group G in VLAN A will not be filtered inside the West cloud, if there are receivers for (VLAN A, group G) in East and vice versa. If the cut set RBridges do nothing, then a multicast for VLAN B, group G would be filtered inside the West cloud, since RBridges inside the East cloud will only be requesting receipt of VLAN A, group G. To solve this problem RB1 MUST report connectivity to an IPv4 multicast router and an IPv6 multicast router for both VLANs A and B. 8. Endnode Advertisements by cut set RBridges TRILL allows RBridges to optionally advertise attached endnodes. This endnode advertisement uses the TRILL ESADI (End System Address Distribution Information) protocol. If cut set RBridge RB1 is translating VLAN A (in East) to VLAN B (in West), and RB1 is doing ESADI for its attached endnodes in VLAN A, it should transmit the ESADI advertisement tagged with VLAN A when forwarding onto ports labeled as "East", and transmit the same ESADI advertisement when forwarding onto ports labeled as "West". An East VLAN-A ESADI generated by any RBridge in East will automatically get translated into a VLAN B ESADI when forwarding into West, because ESADIs are handled just like ordinary encapsulated data frames, the VLAN tag to which the ESADI belongs is the VLAN tag on the inner data frame, and that VLAN tag will be translated by (properly configured) cut set RBridges when forwarding between East and West. R. Perlman, et al. [Page 7] INTERNET-DRAFT RBridge VLAN Mapping 9. IANA Considerations This document requires no IANA actions. This section should be deleted by the RFC Editor before publication. 10. Security Considerations See [RFCtrill] for general RBridge Security Considerations. If cut set RBridges have misconfigured VLAN mappings, VLANs may be inadvertently partitioned or inadvertently merged and frames may be delivered in the wrong VLAN. However, misconfiguration of VLAN mapping will not cause loops. R. Perlman, et al. [Page 8] INTERNET-DRAFT RBridge VLAN Mapping 11. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997 [RFCtrill] R. Perlman, D. Eastlake, D. Dutt, S. Gai, and A. Ghanwani, draft-ietf-trill-rbridge-protocol-14.txt, work in progress. 12. Informative References None. R. Perlman, et al. [Page 9] INTERNET-DRAFT RBridge VLAN Mapping Appendix Z: Change Summary RFC Editor: Please delete this section on publication. 1. Because RBridges can not tell what cloud other RBridges are in, drop the "optimized" option for advertising multicast listeners and require the advertisement of multicast router connectivity. 2. Specify that the cloud connectivity must be specified for all cut set RBridges and that cloud IDs are manually configured and are 16 bit. 3. Expand rules for VLAN ID mapping/handling at a cut set RBridge so as to drop frames that are for a VLAN ID to which another VLAN ID is being mapped. (See Section 3.) 4. Add mention of "VLAN ID translation", the 802.1 name for VLAN mapping. 5. Minor editing changes. R. Perlman, et al. [Page 10] INTERNET-DRAFT RBridge VLAN Mapping Authors' Addresses Radia Perlman Sun Microsystems 16 Network Circle Menlo Park, CA 94025 USA Phone: +1-650-960-1300 Email: Radia.Perlman@sun.com Dinesh G. Dutt Cisco Systems 170 Tasman Drive San Jose, CA 95134-1706 USA Phone: +1-408-527-0955 Email: ddutt@cisco.com Donald Eastlake 3rd Stellar Switches, Inc. 155 Beaver Street Milford, MA 01757 USA Tel: +1-508-634-2066 Email: d3e3e3@gmail.com R. Perlman, et al. [Page 11] INTERNET-DRAFT RBridge VLAN Mapping Copyright, Disclaimer, and Additional IPR Provisions Copyright (c) 2009 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 in effect on the date of publication of this document (http://trustee.ietf.org/license-info). 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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. R. Perlman, et al. [Page 12]