cancel
Showing results for 
Search instead for 
Did you mean: 
cancel
218
Views
0
Helpful
2
Replies

Is it legtimate to bridge between 2 VLAN's on a Catalyst 3548-XL

admin_2
Level 3
Level 3

We are deploying an OEM product called Big-IP that functions something like Cisco Local Director. It is used for server load balancing and needs to act as bridge between the client and a backend VLAN housing a server farm. To conserve hardware, I'd like to take a Catalyst 3524XL-EN (or a 3548XL-EN)and split it into 2 VLAN's. Is there a problem bridging between the 2 VLAN's? i.e. Does the VLAN 1 side of the switch learn everything about what's in VLAN 2 exclusively via the bridge (and vice-versa)?

2 Replies 2

Not applicable

No, VLAN1 does not learn anything about VLAN2 by bridging. The only way VLAN1 would communicate with VLAN2 is by routing.

Frederic Vanderbecq
Cisco Employee
Cisco Employee

There are no real problems linking 2 VLANs using a bridge. You have to be careful with your spanning-tree to avoid having ports into blocking state while they should not (this due to the fact that the 2 VLANs are merged in one big VLAN). You also have to be careful about the spanning-tree diameter. Regarding "learning", MAC addresses existing in VLAN1 may be learned in VLAN2 as the 2 VLANs are being merged by the bridge.