TRILL Working Group Yizhou Li
Internet Draft Weiguo Hao
Intended status: Standards Track Huawei Technologies
Radia Perlman
Intel Labs
Naveen Nimmu
Broadcom
S. Chatterjee
IP Infusion
Sunny Rajagopalan
IBM
Expires: July 2013 January 15, 2013
VLAN based Tree Selection for Multi-destination Frames
draft-yizhou-trill-tree-selection-02.txt
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Internet-Draft VLAN based Tree Selection January 2013
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Abstract
TRILL uses the distribution trees to deliver multi-destination frames.
Multiple trees can be used by an ingress RBridge for different flow
based on VLAN and/or multicast group. Different ingress RBridges may
choose different distribution trees for the same VLAN and/or
multicast group traffic. Distribution trees are normally pruned based
on VLAN.
For any RBridge RBn, if RBn has downstream receivers of VLAN x in a
distribution tree t, there will be an entry of (t, x, port list) in
the multicast forwarding table on RBn. If there are n trees and m
VLANs, the multicast forwarding table size on RBn is typically n*m
entries. The value of m is up to 4096 and n is the total number of
distribution trees in the campus. If fine grained labeling is
implemented or finer granularity filtering such as VLAN plus L2/L3
multicast address is used for pruning, the multicast forwarding table
size further increases dramatically. TRILL multicast forwarding table
size is limited by hardware and L3 multicasting may share the same
table with it in hardware implementations. Therefore multicast table
entry is a precious resource. This document specifies a VLAN based
tree selection mechanism to reduce the TRILL multicast forwarding
table size on RBridge.
Table of Contents
1. Introduction ................................................ 3
1.1. Background ............................................. 3
1.2. Motivations ............................................ 4
2. Conventions used in this document............................ 6
3. VLAN based Tree Selection.................................... 6
3.1. Overview ............................................... 6
3.2. Sub-TLVs for the Router Capability TLV ................. 8
3.2.1. The Tree Identifier and VLANs Sub-TLV ............. 8
3.2.2. The Tree and VLANs Used Sub-TLV ................... 9
3.3. Detailed Processing..................................... 9
Li, et al. Expires July 15, 2013 [Page 2]
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