• The I-BEB contains the I-Component of the MAC-in-MAC bridge. It performs B-MAC encapsulation
and inserts the I-SIDs based on the provider VLAN tags (S-tags), customer VLAN tags (C-tags), or
S-tag/C-tag pairs.
• The IB-BEB contains one or more I-Components and a single B-Component interconnected through a
LAN segment.
Only IB-BEBs are supported on Cisco ASR 9000 Series Routers. Cisco IOS XR supports IB-BEB bridge type
at the Edge node.
Note
IB-BEB
The IB-BEB contains both the I-Component and the B-Component. The bridge selects the B-MAC and inserts
the I-SID based on the provider VLAN tag (S-tag), the customer VLAN tag (C-tag), or both the S-tag and the
C-tag. It validates the I-SIDs and it transmits and receives frames on the B-VLAN.
The IEEE 802.1ah on Provider Backbone Bridges feature supports all services mandated by the IEEE 802.1ah
standard and extends the services to provides these additional functionalities:
• S-Tagged Service:
• In multiplexed environments each S-tag maps to an I-SID and may be retained or removed.
• In bundled environments multiple S-tags map to the same I-SID and the S-tags must be retained.
• C-Tagged Service:
• In multiplexed environments each C-tag maps to an I-SID and may be retained or removed.
• In bundled environments multiple C-tags map to the same I-SID and the C-tags must be retained.
• S/C-Tagged Service:
• In multiplexed environments each S-tag/C-tag pair maps to an I-SID. The S-tag or the S-tag/C-tag
pair may be retained or removed.
• In bundled environments multiple S-tag/C-tags pairs map to the same I-SID and the S-tag/C-tag
pair must be retained.
• Port-based Service
• A port-based service interface is delivered on a Customer Network Port (CNP). A port-based service
interface may attach to a C-VLAN Bridge, 802.1d bridge, router or end-station. The service provided
by this interface forwards all frames without an S-Tag over the backbone on a single backbone
service instance. A port-based interface discards all frames with an S-Tag that have non-null VLAN
IDs.
This example shows how to configure a port-based service:
interface GigabitEthernet0/0/0/10.100 l2transport
encapsulation untagged
--> Creates an EFP for untagged frames.
interface GigabitEthernet0/0/0/10.101 l2transport
encapsulation dot1ad priority-tagged
L2VPN and Ethernet Services Configuration Guide for Cisco ASR 9000 Series Routers, IOS XR Release 6.3.x
359
Implementing IEEE 802.1ah Provider Backbone Bridge
IB-BEB
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