Help please - inter-VLAN Routing

[JRJSmith_WKL]

We have two buildings connected through a fibre link.

One building has a L3 switch, which has been configured with VLANs for each classroom and one VLAN for the server room. We can connect between the VLANs without problem.

The second building has been configured with VLANs for each of its classrooms and another for its server room. Using router-on-a-stick, these VLANs can interconnect.

The fibre connection between the server rooms has been configured to carry all the VLANs tagged using 802.1q.

All VLANs are unique.

However, we cannot get connection between a VLAN in building 1 and another VLAN in building 2.

I suspect that this is because there is no port in the Building 1 L3 switch that is the untagged (default gateway) for VLANs in Building 2 and, similarly, the L2 switch in Building 2 has no untagged (default gateway) port for VLANs in Building 1.

Is it necessary for me to configure the router-on-a-stick in Building 2 to perform all the inter-VLAN routing? I'd prefer not to do this as most of the traffic will remain within the discreet buildings but we do require occasional traffic between the buildings.

I'd appreciate any suggestions regarding configuring inter-VLAN routing retaining the L3 switch inter-VLAN routing in Building 1 and the router-on-a-stick inter-VLAN routing in Building 2, if practical.

Many thanks

Joe.

[JRJSmith_WKL]

Hi Rick,

Here is the latest status on my attempts to achieve the four requirements that we have.

I've managed to get the L3 device in BuildingA to communicate with the R-O-A-S f 0/1.500 sub-interface, as described above. I don't know why it didn't work the last time - obviously, finger-trouble on my part.

So, from my first post on Apr 19, I've now got solutions 1-3 working.

I'm puzzling over solution 4, however, because the only connection between the buildings now is a routed connection between f 0/1.500 on the R-O-A-S and the other Fast Ethernet interface on that machine. (The fibre connection between the buildings is a Layer 2 Ethernet connection from the port in the L3 device and the f 0/1 interface on the R-O-A-S). I'm not sure that I'll be able to trunk all the VLANs over a routed connection, seeing that VLAN trunking occurs at Layer 2 and, of course, routing occurs at Layer 3.

Is it possible to trunk VLANs over a routed interface?

If anyone has done this, please describe how.

Many thanks

Joe.