Unable to get Bridge-Domain to work on an ISR4351/K9.

[James L]

Hi. I'm having difficulty getting Bridge-Domain to work on my ISR4351/K9 Router.

Topology is as follows:

Router Interface g0/0/1 & 2 will go into a Firewall eventually but for testing I have them connected to a unmanaged hub and my pc is connected to this to create a network.

When I only have 1 link up on the Router (either 1 or 2) I PC can ping the Router no problems but when I connect the 2nd cable I start to get a loop... I know this because interface counters on g0/0/1 & 2 start to increment like crazy up to the 400Mb limit of my Router.

Config is as follows:

bridge-domain 1 

!

bridge irb

!

interface GigabitEthernet0/0/1
description inside
no ip address
load-interval 30
negotiation auto
service instance 1 ethernet
encapsulation untagged
bridge-domain 1
!
interface GigabitEthernet0/0/2
description inside
no ip address
load-interval 30
negotiation auto
service instance 1 ethernet
encapsulation untagged
bridge-domain 1

!

interface BDI1
ip address 123.123.123.1 255.255.255.0

Must be missing something really simple!

Anybody help will be greatly appreciated.

TIA.

[paulowenkirk]

I was having the similar sort of issue with two switch ports in the same vlan to the bridged interfaces creating a loop.
Adding the command l2protocol forward stp under the service instance allowed the switch interfaces to see the bdpu's and block one of the ports on the switch