Layer 2 To Layer; Layer 3 To Layer - Cisco ASR1002 - ASR 1002 Router Software Configuration Manual

Information About Bridge Domain Interfaces
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Support for IP Forwarding
Bridge domain interface supports the following IP forwarding features:
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Packet Forwarding
A bridge domain interface provides bridging and forwarding services between the Layer 2 and Layer 3
network infrastructure.

Layer 2 to Layer 3

During a packet flow from a Layer 2 network to a Layer 3 network, if the destination MAC address of
the incoming packet matches the bridge domain interface MAC address, or if the destination MAC
address is a multicast address, the packet or a copy of the packet is forwarded to the bridge domain
interface.
MAC address learning cannot not be performed on the bridge domain interface.
Note
In a bridge domain, when flooding unknown unicast frames, bridge domain interface is not included.
Note

Layer 3 to Layer 2

When a packet arrives at a Layer 3 physical interface of a router, a route lookup action is performed. If
route lookup points to a bridge domain interface, then the bridge domain interface adds the layer 2
encapsulation and forwards the frame to the corresponding bridge domain. The byte counters are
updated.
Cisco ASR 1000 Series Aggregation Services Routers Software Configuration Guide
4
NTP
RARP
SNMP
TCP
Telnet
TFTP
UDP
IPv4 input and output access control lists (ACL)
IPv4 input and output QoS policies. The operations supported for the input and output service
policies on a bridge domain interface are:
Classification
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Marking
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Policing
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IPv4 L3 VRFs
Configuring Bridge Domain Interfaces