Using BVI Interface on router for core switch redundancy??

virtualcontext · ‎04-07-2011

Hello All, I know this must be a noob question, but I just want to make sure I am right. I have a dual core network, and as it is now, I have one 2911 Router acting as a voice gateway for our pri. Originally it was a single connection to Core-A, with the physical interface gi0/0 assigned the ip address.

I had the idea of dual homing the voice gateway so that if we ever lose a core switch, we dont lost the ability to make and take calls.

My question is this: if I create a bvi interface, create a bridge group, put gi0/0 (core a) and gi0/1 (core b) in the bridge group, will this create a spanning tree loop?

attached pic is related - this is the design. vlan 20 is our voip network, and the CUCM, the CUPS Server, the Phones at our corporate office and the 2911 are on the same vlan.

Please take a look and let me know if this does open me up to loops. I am not thrilled about just doing it and "seeing if it works" and I cannot find any documentation on the subject, which makes me extra wary.

Thanks everybody!

virtualcontext · ‎04-07-2011

Nevermind. It looks like it is working...

dfw-2921#show spanning-tree

Bridge group 1 is executing the ieee compatible Spanning Tree protocol
Bridge Identifier has priority 32768, address d0d0.fdd3.fec0
Configured hello time 2, max age 20, forward delay 15
Current root has priority 8212, address c84c.7566.8f80
Root port is 3 (GigabitEthernet0/0), cost of root path is 4
Topology change flag not set, detected flag not set
Number of topology changes 1 last change occurred 00:07:22 ago
          from GigabitEthernet0/0
Times: hold 1, topology change 35, notification 2
          hello 2, max age 20, forward delay 15
Timers: hello 0, topology change 0, notification 0, aging 300

Port 3 (GigabitEthernet0/0) of Bridge group 1 is forwarding
   Port path cost 4, Port priority 128, Port Identifier 128.3.
   Designated root has priority 8212, address c84c.7566.8f80
   Designated bridge has priority 8212, address c84c.7566.8f80
   Designated port id is 128.2, designated path cost 0
   Timers: message age 1, forward delay 0, hold 0
   Number of transitions to forwarding state: 1
   BPDU: sent 2, received 224

Port 4 (GigabitEthernet0/1) of Bridge group 1 is blocking
   Port path cost 4, Port priority 128, Port Identifier 128.4.
   Designated root has priority 8212, address c84c.7566.8f80
   Designated bridge has priority 16404, address 503d.e5eb.e480
   Designated port id is 128.2, designated path cost 4
   Timers: message age 2, forward delay 0, hold 0
   Number of transitions to forwarding state: 0
   BPDU: sent 1, received 56

dfw-2921#