Bridge Group question... "Encapsulation Failed" on a BVI...

Hi Jonathan,

Bridging is Layer 2, IP is Layer 3. So you have no path for Layer 3 between the devices, thats why your encapsulation failed. It goes back to near the beginning of your post -

Thats because a Bridge group only Bridges by default. You are probably thinking of -

^^^^^^^^ Meaning all data EXCEPT IP would be bridged on that link. So your problem is that IP addressing is irrelevant at the frame (bridge) level and routing of IP addressing does not exist.

A BVI allows you to attach Layer 3 properties to a Layer 2 entity and nothing more. You still need to tell the Router what to do with Layer

Consider this as an example that may help - I had one site that had a Router connecting the local Ethernet segment to a 512Kb/s Frame-Relay WAN link. They needed MAC filtering to be applied, however because a Router Ethernet interface normally operates in Layer 3 mode, a MAC ACL is not valid. If I BRIDGED the Ethernet to the WAN link, then effectively the LAN would be slowed from 10Mb to the speed of the Frame-Relay WAN (512Kb/s), so I converted the Ethernet to Bridged mode, Bridged it to a BVI, meaning the Ethernet was in Layer 2 mode, ran at Ethernet speed, and so could take the MAC ACL, and the BVI allowed me to ROUTE off that interface, meaning the Ethernet was not restricted by the WAN link speed.

Cheers...............pk.