Virtual Private LAN Service (VPLS) Using BGP for Auto-Discovery and Signaling
RFC 4761
Network Working Group K. Kompella, Ed.
Request for Comments: 4761 Y. Rekhter, Ed.
Category: Standards Track Juniper Networks
January 2007
Virtual Private LAN Service (VPLS)
Using BGP for Auto-Discovery and Signaling
Status of This Memo
This document specifies an Internet standards track protocol for the
Internet community, and requests discussion and suggestions for
improvements. Please refer to the current edition of the "Internet
Official Protocol Standards" (STD 1) for the standardization state
and status of this protocol. Distribution of this memo is unlimited.
Copyright Notice
Copyright (C) The IETF Trust (2007).
IESG Note
The L2VPN Working Group produced two separate documents, RFC 4762 and
this document, that ultimately perform similar functions in different
manners. Be aware that each method is commonly referred to as "VPLS"
even though they are distinct and incompatible with one another.
Abstract
Virtual Private LAN Service (VPLS), also known as Transparent LAN
Service and Virtual Private Switched Network service, is a useful
Service Provider offering. The service offers a Layer 2 Virtual
Private Network (VPN); however, in the case of VPLS, the customers in
the VPN are connected by a multipoint Ethernet LAN, in contrast to
the usual Layer 2 VPNs, which are point-to-point in nature.
This document describes the functions required to offer VPLS, a
mechanism for signaling a VPLS, and rules for forwarding VPLS frames
across a packet switched network.
Kompella & Rekhter Standards Track [Page 1]
RFC 4761 BGP Auto-Discovery and Signaling for VPLS January 2007
Table of Contents
1. Introduction ....................................................3
1.1. Scope of This Document .....................................3
1.2. Conventions Used in This Document ..........................4
2. Functional Model ................................................4
2.1. Terminology ................................................5
2.2. Assumptions ................................................5
2.3. Interactions ...............................................6
3. Control Plane ...................................................6
3.1. Auto-Discovery .............................................7
3.1.1. Functions ...........................................7
3.1.2. Protocol Specification ..............................7
3.2. Signaling ..................................................8
3.2.1. Label Blocks ........................................8
3.2.2. VPLS BGP NLRI .......................................9
3.2.3. PW Setup and Teardown ..............................10
3.2.4. Signaling PE Capabilities ..........................10
3.3. BGP VPLS Operation ........................................11
3.4. Multi-AS VPLS .............................................13
3.4.1. Method (a): VPLS-to-VPLS Connections at the ASBRs ..13
3.4.2. Method (b): EBGP Redistribution of VPLS
Information between ASBRs ..........................14
3.4.3. Method (c): Multi-Hop EBGP Redistribution
of VPLS Information ................................15
3.4.4. Allocation of VE IDs across Multiple ASes ..........16
3.5. Multi-homing and Path Selection ...........................16
3.6. Hierarchical BGP VPLS .....................................17
4. Data Plane .....................................................18
4.1. Encapsulation .............................................18
4.2. Forwarding ................................................18
4.2.1. MAC Address Learning ...............................18
4.2.2. Aging ..............................................19
4.2.3. Flooding ...........................................19
4.2.4. Broadcast and Multicast ............................20
4.2.5. "Split Horizon" Forwarding .........................20
4.2.6. Qualified and Unqualified Learning .................21
4.2.7. Class of Service ...................................21
5. Deployment Options .............................................21
6. Security Considerations ........................................22
7. IANA Considerations ............................................23
8. References .....................................................24
8.1. Normative References ......................................24
8.2. Informative References ....................................24
Appendix A. Contributors .........................................26
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