Bridge Domain Interface (BDI): Explained & Configuration [Cisco IOS-XE]

This concept is very similar to BVI (which runs on Cisco IOS) but for devices running IOS-XE.

Below are some of the common terminologies used :

• Bridge domain represents a Layer 2 broadcast domain.

• Bridge domain interface is a logical interface that allows bidirectional flow of traffic between a Layer-2 bridged network and a Layer-3 routed network.

• Ethernet Virtual Circuit (EVC) is an end-to-end representation of a single instance of a Layer-2 service being offered by a provider to a customer. In the Cisco EVC Framework, the bridge domains are made up of one or more Layer-2 interfaces known as Service Instances. A Service Instance is the instantiation of an EVC on a given port on a given router. Service instance is associated with a bridge domain based on the configuration.

BDI Configuration use cases:

– Use case1: Fa0/1 on both the switches are Layer-3 interfaces and are in the same broadcast domain:

Note: BDI interface configuration on ASR is not required if the motive is to just establish connectivity between the two switches.

We can verify by Pinging SW2 Interface Fa0/1 from SW1:

ASR1K#ping 10.1.1.3

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 10.1.1.3, timeout is 2 seconds:

!!!!!

Success rate is 100 percent (5/5), round-trip min/avg/max = 1/4/9 ms

• Note:

If you want to route outside of the ASR, a Bridge Domain interface (BDI) configuration is needed. To do this, configure a Bridge Domain Interface on the router using: “interface BDI100” command.

Bridge Domain Interface Configuration:

ASR1K# conf t
ASR1K(config)#interface BDI100
ASR1K(config-if)#ip address 10.1.1.2 255.255.255.0

– Use case2: Bridge multiple vlans between the two switches:

Configure separate Ethernet virtual circuits (EVC) under the physical interface for each of the VLANs. Bridge-domain is not supported under the sub-interface.

Here we have two VLANs. Vlan 100 and VLAN 200 to be bridged:

Ping int vlan100 and vlan200 on SW2 from SW1:

BGL.Q.16-3500-1#ping 10.1.1.3

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 10.1.1.3, timeout is 2 seconds:

!!!!!

Success rate is 100 percent (5/5), round-trip min/avg/max = 1/4/9 ms

BGL.Q.16-3500-1#ping 20.1.1.3

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 20.1.1.3, timeout is 2 seconds:

!!!!!

Success rate is 100 percent (5/5), round-trip min/avg/max = 1/2/9 ms

More about EVC: https://community.cisco.com/t5/networking-documents/understanding-ethernet-virtual-circuits-evc/ta-p/3108219

The equivalent of BDI (IOS-XE platform) in IOS platform is Bridge-group Virtual Interface (BVI)

you can check Bridge-group Virtual Interface (BVI) in the article below: