Network Working Group Eric Gray Internet Draft Ericsson Expires: May, 2008 Intended Status: Informational November 11, 2007 Issues and Approaches to Scaling RBridge Deployments draft-gray-rbridge-scaling-00.txt Status of this Memo By submitting this Internet-Draft, each author represents that any applicable patent or other IPR claims of which he or she is aware have been or will be disclosed, and any of which he or she becomes aware will be disclosed, in accordance with Section 6 of BCP 79. 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/ietf/1id-abstracts.txt The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html This Internet-Draft will expire on May 11, 2008. Abstract RBridges are link layer (L2) devices that use routing protocols as a control plane. They combine several of the benefits of the link layer with network layer routing benefits. RBridges may use existing link state routing (without requiring configuration) to improve RBridge to RBridge aggregate throughput. RBridges also Gray Expires May, 2008 [Page 1] Internet-Draft Scaling RBridge Deployments November 2007 provide support for IP multicast and IP address resolution optimizations. They are intended to be applicable to similar L2 network sizes as conventional bridges and are intended to be backward compatible with those bridges as both ingress/egress and transit. They also support VLANs (although this generally requires configuration) and otherwise attempt to retain as much 'plug and play' as is already available in existing bridges. There has been a lot of discussion within the TRILL working group about the potential for scaling issues when using IS-IS in combination with (possibly as many as 4K) VLANs. This document is intended to provide information on potential scaling issues and the possible solutions that may be applied in deploying RBridges. Gray Expires May, 2008 [Page 2] Internet-Draft Scaling RBridge Deployments November 2007 Table of Contents Introduction...................................................4 1.1. Terminology............................................4 1.2. Routing Protocol Operation.............................5 1.3. Other Bridging and Ethernet Protocol Operations........5 2. Scaling Issues With IS-IS in Combination with VLANs.........5 2.1. Peering Complexity.....................................5 2.2. Designated RBridge Election and Load Splitting.........5 2.3. Messaging Complexity and Message Length................6 Security Considerations........................................6 IANA Considerations............................................6 Acknowledgments................................................6 References.....................................................6 1.4. Normative References...................................6 1.5. Informative References.................................6 Author's Addresses.............................................6 Intellectual Property Statement................................7 Disclaimer of Validity.........................................7 Copyright Statement............................................7 Acknowledgment.................................................8 Gray Expires May, 2008 [Page 3] Internet-Draft Scaling RBridge Deployments November 2007 Introduction This document describes issues with, and potential solutions for, scaling deployments of RBridge standard implementations in combination with standard VLANs. 1.1. Terminology The following terminology is used, as described in this section, throughout this document. o IS-IS: Intermediate System to Intermediate System routing protocol. See [2] for further information on IS-IS. o LAN: Local Area Network, is a computer network covering a small geographic area, like a home, office, or group of buildings, e.g., as based on IEEE 802.3 technology, see also IEEE 802.1Q-2005, Section 3.11 [3]. o Spanning Tree Protocol (STP): an Ethernet (802.1D) protocol for establishing and maintaining a single spanning tree among all the bridges on a local Ethernet segment. Also, Rapid Spanning Tree Protocol (RSTP). In this document, STP and RSTP are considered to be the same. o SPF: Shortest Path First - an algorithm name associated with routing, used to determine a shortest path graph traversal. o TRILL: Transparent Interconnect over Lots of Links - the working group and working name for the problem domain to be addressed in this document. o VLAN: Virtual Local Area Network, see IEEE 802.1Q-2005 [3]. o Adjacent RBridges: RBridges that communicate directly with each other without relay through other RBridges. o Designated RBridge (DR): the RBridge that is elected to handle ingress and egress traffic to a particular Ethernet link having shared access among multiple RBridges; that RBridge is such a link's "Designated RBridge". The Designated RBridge is determined by an election process among those RBridges having shared access via a single LAN. Gray Expires May, 2008 [Page 4] Internet-Draft Scaling RBridge Deployments November 2007 o Edge RBridge (edge of a TRILL Campus): describes RBridges that serve to ingress frames into the TRILL Campus and egress frames from the TRILL Campus. L2 frames transiting an TRILL Campus enter, and leave, it via an edge RBridge. o Peer RBridge: The term "Peer RBridge", or (where usage is not ambiguous) the term "Peer", are used in the RBridge context to refer to any of the RBridges that make up a TRILL campus. o RBridge: a logical device as described in this document, which incorporate both routing and bridging features, thus allowing for the achievement of TRILL Architecture goals. A single RBridge device which can cooperate with other RBridge devices to create a TRILL Campus. o TRILL Campus: this term, or the term "Campus" (where usage is not ambiguous) is used in the RBridge context to refer to the set of cooperating RBridges and TRILL Links that connect them to each other. o TRILL Link: this term, or the term "Link" (where its usage is not ambiguous) is used in the RBridge context to refer to the Layer 2 connection that exists either between RBridges, or between an RBridge and Ethernet end stations. 1.2. Routing Protocol Operation The details of routing protocol operation are as specified for IS-IS. 1.3. Other Bridging and Ethernet Protocol Operations TBD. 2. Scaling Issues With IS-IS in Combination with VLANs TBD. 2.1. Peering Complexity Details to be provided. 2.2. Designated RBridge Election and Load Splitting Details to be provided. Gray Expires May, 2008 [Page 5] Internet-Draft Scaling RBridge Deployments November 2007 2.3. Messaging Complexity and Message Length Details to be provided. Security Considerations TBD. IANA Considerations TBD. Acknowledgments TBD. References 1.4. Normative References TBD. 1.5. Informative References [1] 802.1D-2004 IEEE Standard for Local and Metropolitan Area Networks: Media Access Control (MAC) Bridges [2] Callon, R., "Use of OSI IS-IS for Routing in TCP/IP and Dual Environments", RFC 1195, December, 1990. [3] 802.1Q-2005 IEEE Standard for Local and Metropolitan Area Networks: Virtual Bridged Local Area Networks (Incorporates IEEE Std 802.1Q-1998, IEEE Std 802.1uT-2001, IEEE Std 802.1vT-2001, and IEEE 802.1sT-2002) Author's Addresses Editor: Eric Gray Ericsson 900 Chelmsford Street Lowell, MA, 01851 Phone: +1 (978) 275-7470 EMail: Eric.Gray@Ericsson.com Gray Expires May, 2008 [Page 6] Internet-Draft Scaling RBridge Deployments November 2007 Intellectual Property Statement The IETF takes no position regarding the validity or scope of any Intellectual Property Rights or other rights that might be claimed to pertain to the implementation or use of the technology described in this document or the extent to which any license under such rights might or might not be available; nor does it represent that it has made any independent effort to identify any such rights. Information on the procedures with respect to rights in RFC documents can be found in BCP 78 and BCP 79. 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Disclaimer of Validity This document and the information contained herein are provided on an "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY, THE IETF TRUST AND THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. Copyright Statement Copyright (C) The IETF Trust (2007). This document is subject to the rights, licenses and restrictions contained in BCP 78, and except as set forth therein, the authors retain all their rights. Gray Expires May, 2008 [Page 7] Internet-Draft Scaling RBridge Deployments November 2007 Acknowledgment Funding for the RFC Editor function is currently provided by the Internet Society. Gray Expires May, 2008 [Page 8]