Cisco Support Community
Showing results for 
Search instead for 
Did you mean: 
New Member

layer 3 switch Help


I am connecting a 3550 Cisco switch to an extreme layer 3 switch is a different product.

The extreme switch is the core switch running all the Vlans for this office.

I am connecting another layer 3 switch to it because I have a laser connecting to it in order to connect another building to it.

The 2 buildings are on differentr network ranges so I am going to use a routed hop to connect the 2 buildings.

My query I have is how would I setup the cisco 3550 that is connecting to this extreme layer 3 switch.

Do i just add the port into one of the Vlans on the extreme......

My objective is to get the 2 buildings connected and be able to see each other by routing even though the networks are different.

If I set the port on the cisco connecting to the extreme switch on the Vlan of the extreme switch will that do the trick or do I need to configure routes on the 3550 pointing to the differen t Vlan subnets.I should not have to because the switch will take care of that right....

Any help would be great

Cisco Employee

Re: layer 3 switch Help

If you are doing all of your Inter-VLAN routing on the Extreme switch, then all you should need is a 802.1q trunk between the 3550 and the Extreme switch assuming there will be multiple VLANs on the 3550.

If all the ports on the 3550 are on the same VLAN, then just add the ports on the 3550 and Extreme to the appropriate VLAN and you should be good to go.

hope that helps.

New Member

Re: layer 3 switch Help


Thanks so much.

Just another quicky.

The 3550 is only in one vlan but the port that connects to the laser is a routed port.This should not make a difference because I am just routing across the laser through that port.

Do I need to add any routes into the 3550 pointing to the Vlans on the extreme switch so that the networks at the other building can see the Vlans on the extreme switch.

once again I appreciate your help with this.

Re: layer 3 switch Help


is my understanding correct that there is no trunk between your extreme and 3550, the port on 3550 is configured with IP address and "no switchport" command?

And all the other ports on the 3550 are switchports in one VLANx?

If yes,

you need either

1) a dynamic routing protocol between the extreme and 3550


2) static routes to the extreme's VLANs on the 3550 and vice versa a static route to 3550's VLANx on the extreme


3) a default route to the extreme on the 3550 and a static route to 3550's VLANx on the extreme.



CreatePlease to create content