Backbone Edge Bridges
Figure 41: Provider Back Bone Network Topology
Backbone Edge Bridges
Backbone edge bridges (BEBs) can contain either an I-Component or a B-Component. The I-Component
maps service VLAN identifiers (S-VIDs) to service instance identifiers (I-SIDs) and adds a provider backbone
bridge (PBB) header without a backbone VLAN tag (B-Tag). The B-Component maps I-SIDs to backbone
VIDs (B-VIDs) and adds a PBB header with a B-Tag.
The IEEE 802.1ah standard specifies these three types of BEBs:
• The B-BEB contains the B-Component of the MAC-in-MAC bridge. It validates the I-SIDs and maps
the frames onto the backbone VLAN (B-VLAN). It also switches traffic based on the B-VLANS within
the core bridge.
L2VPN and Ethernet Services Configuration Guide for Cisco ASR 9000 Series Routers, IOS XR Release 6.3.x
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Implementing IEEE 802.1ah Provider Backbone Bridge