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Cisco ASR 1000 Series Aggregation Services Routers Software Configuration Guide
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Chapter 11 Configuring Bridge Domain Interfaces
Creating or Deleting a Bridge Domain Interface
During a Layer 2 lookup on a bridge domain to which the bridge domain interface belongs, the bridge
domain forwards the packets to the correct service instance based on the destination MAC address.
Link States of a Bridge Domain and a Bridge Domain Interface
Bridge domain interface acts as a routable IOS interface on Layer 3 and as a port on a bridge domain.
Both bridge domain interfaces and bridge domains operate with individual administrative states.
Shutting down a bridge domain interface stops the Layer 3 data service, but does not override or impact
the state of the associated bridge domain.
Shutting down a bridge domain stops Layer 2 forwarding across all the associated members including
service instances and bridge domain interfaces. The operational state of a bridge domain is influenced
by associated service instances. Bridge domain interface cannot be operational unless one of the
associated service instance is up.
Note
Because a bridge domain interface is an internal interface, the operational state of bridge domain
interface does not affect the bridge domain operational state.
Bridge Domain Interface Statistics
For virtual interfaces, such as the bridge domain interface, protocol counters are periodically queried
from the QFP.
When packets flow from a Layer 2 bridge domain network to a Layer 3 routing network through the
bridge domain interface, the packets are treated as bridge domain interface input packets and bytes.
When packets arrive at a Layer 3 interface and are forwarded through the bridge domain interface to a
Layer 2 bridge domain, the packets are treated as output packets and bytes, and the counters are updated
accordingly.
The
show interfaces accounting
command is used to display the statistics. The
show interface
<if-name>
command is used to display the overall count of the packets and bytes that are transmitted
and received.
Creating or Deleting a Bridge Domain Interface
When you define an interface or subinterface for a Cisco IOS router, you name it and specify how it is
assigned an IP address.You can create a bridge domain interface before adding a bridge domain to the
system, this new bridge domain interface will be activated after the associated bridge domain is
configured.
Note
When a bridge domain interface is created, a bridge domain is automatically created.
When both bridge domain interface and bridge domain are created, the system maintains the required
associations for mapping the bridge domain-bridge domain interface pair.
The mapping of bridge domain and bridge domain interface is maintained in the system. The bridge
domain interface uses the index of the associated bridge domain to show the association.
