VLANS across routers

benbuiltpc

Is the following setup possible:

(VLAN10)--Switch1--Router1--WAN--Router2--Switch2--(VLAN10)

Basically, having the same VLAN across multiple locations, that are segmented by routers.

Ex:

Router1:
Fast 0/0: 172.25.4.1 /23
Fast 0/0.10: 172.25.18.2 /23
Ser 0/0: 172.25.0.17 /30

Router2:
Fast 0/0: 172.25.10.1 /23
Fast 0/0.10: 172.25.18.5 /23
Ser 0/0: 172.25.0.18 /30

The idea is to have the 172.25.18.1-172.25.19.254 network distributed across 8 buildings (VoIP phones, to be precise). Each building must maintain its current 172.25.x.x /23 scheme. My guess is that since each router thinks the 172.25.18.x network is directly connected, this may not work.

Any ideas?

Thanks

georgemc

Won't work across routers. You can't have the same subnet on 2 separate routers unless they are in the same local segment, such as when running HSRP.

What kind of backbone network are you running between the buildings (ATM, GIG-E, T1/E1, etc.)?

deneb829

Can you bridge the VLAN through the routers?

mp3spy

deneb829 wrote:

Can you bridge the VLAN through the routers?

Still won't work because Routers break up the Broadcast domain. Routers can fowards packets to other LAN segments/VLANS. Just utilize a class C and break the network into seperate subnets within that range...