I'm new to interface bridging, and I have an ISR4431 running 03.16.04b.S on which I need to bridge between two interfaces for two hosts: One interface is connecting directly to a host, the other to a switch (diagram below). I initially configured it as documented here, but this setup wasn't working in my environment, so I've read everything I can find on BDIs and played with all the related commands for a few days... I could use some input, nothing is working.
I currently have it working so L3 traffic is handled properly (both hosts can reach the BDI IP and can reach/be reached from other subnets), but L2 traffic doesn't seem to work-- the hosts can't reach each other (there was a brief blip twice where ARP resolved on one host for the other, but it went back to "incomplete" when I tried to SSH between them).
If I do a sh mac add add [host1/host2 MAC] on either of the switches, it will show the host's MAC, VLAN111, and interface correctly. I'm guessing something is wrong on the router that's stopping it from forwarding L2 traffic.
Here are the current configs:
interface GigabitEthernet0/0/2 description DLink Host .2 no ip address negotiation auto service instance 111 ethernet encapsulation untagged bridge-domain 111 ! interface GigabitEthernet0/0/3 description DLink Host .3 via Switch no ip address negotiation auto service instance 111 ethernet encapsulation untagged l2protocol peer stp bridge-domain 111 ! interface BDI111 mac-address 0000.1221.3443 ip address 18.104.22.168 255.255.255.248 no cdp enable end
interface GigabitEthernet1/1 description DLink Router G0/0/3 switchport mode access switchport access vlan 111 no cdp enable spanning-tree bpduguard enable ! interface GigabitEthernet1/2 description DLink Switch2 G1/1 switchport trunk native vlan 200 switchport mode trunk switchport nonegotiate !
interface GigabitEthernet1/1 description ULink Switch 1 G1/2 switchport trunk native vlan 200 switchport mode trunk switchport nonegotiate ! interface GigabitEthernet1/2 description DLink Host .3 switchport mode access switchport access vlan 111 no cdp enable
Any help is greatly appreciated, I've been stuck on this for a while and am completely out of ideas.
Update 1: I originally had the following commands entered on the router, but in my testing the seemed to be related to BVIs so I removed them. They've been added back now as it doesn't have any negative impact.
bridge irb bridge 111 route ip !Spanning Tree protocol for Bridge Group 7 has not been configured. bridge 111 protocol vlan-bridge !The protocol options I have are dec, ibm, and vlan-bridge
Update 2: I removed the rewrite commands and changed both interfaces to untagged on the router. It's behaving exactly the same without them: Both switches and the router show proper VLAN, interface, and MAC information for each IP, L3 is working, L2 isn't. See the post history for the previous config.