Routing Bridges (RBridges): Base Protocol Specification
RFC 6325

• Status
• IESG evaluation record
• IESG writeups
• Email expansions
• History

• Versions
• 16

Internet Engineering Task Force (IETF)                        R. Perlman
Request for Comments: 6325                                    Intel Labs
Category: Standards Track                                D. Eastlake 3rd
ISSN: 2070-1721                                                   Huawei
                                                                 D. Dutt
                                                                  S. Gai
                                                           Cisco Systems
                                                             A. Ghanwani
                                                                 Brocade
                                                               July 2011

        Routing Bridges (RBridges): Base Protocol Specification

Abstract

   Routing Bridges (RBridges) provide optimal pair-wise forwarding
   without configuration, safe forwarding even during periods of
   temporary loops, and support for multipathing of both unicast and
   multicast traffic.  They achieve these goals using IS-IS routing and
   encapsulation of traffic with a header that includes a hop count.

   RBridges are compatible with previous IEEE 802.1 customer bridges as
   well as IPv4 and IPv6 routers and end nodes.  They are as invisible
   to current IP routers as bridges are and, like routers, they
   terminate the bridge spanning tree protocol.

   The design supports VLANs and the optimization of the distribution of
   multi-destination frames based on VLAN ID and based on IP-derived
   multicast groups.  It also allows unicast forwarding tables at
   transit RBridges to be sized according to the number of RBridges
   (rather than the number of end nodes), which allows their forwarding
   tables to be substantially smaller than in conventional customer
   bridges.

Status of This Memo

   This is an Internet Standards Track document.

   This document is a product of the Internet Engineering Task Force
   (IETF).  It represents the consensus of the IETF community.  It has
   received public review and has been approved for publication by the
   Internet Engineering Steering Group (IESG).  Further information on
   Internet Standards is available in Section 2 of RFC 5741.

   Information about the current status of this document, any errata,
   and how to provide feedback on it may be obtained at
   http://www.rfc-editor.org/info/rfc6325.

Perlman, et al.              Standards Track                    [Page 1]
RFC 6325                    RBridge Protocol                   July 2011

Copyright Notice

   Copyright (c) 2011 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.

   This document may contain material from IETF Documents or IETF
   Contributions published or made publicly available before November
   10, 2008.  The person(s) controlling the copyright in some of this
   material may not have granted the IETF Trust the right to allow
   modifications of such material outside the IETF Standards Process.
   Without obtaining an adequate license from the person(s) controlling
   the copyright in such materials, this document may not be modified
   outside the IETF Standards Process, and derivative works of it may
   not be created outside the IETF Standards Process, except to format
   it for publication as an RFC or to translate it into languages other
   than English.

Perlman, et al.              Standards Track                    [Page 2]
RFC 6325                    RBridge Protocol                   July 2011

Table of Contents

   1. Introduction ....................................................6
      1.1. Algorhyme V2, by Ray Perlner ...............................7
      1.2. Normative Content and Precedence ...........................7
      1.3. Terminology and Notation in This Document ..................7
      1.4. Categories of Layer 2 Frames ...............................8
      1.5. Acronyms ...................................................9
   2. RBridges .......................................................11
      2.1. General Overview ..........................................11
      2.2. End-Station Addresses .....................................12
      2.3. RBridge Encapsulation Architecture ........................13
      2.4. Forwarding Overview .......................................15
           2.4.1. Known-Unicast ......................................16