About L3 switches

[dominique.rossignol]

hi,

is it possible in the same L3 switch to have some ports doing switching and some ports doing routing.

For exemple for 24 ports: 20 ports doing switching between some VLANs, and 4 ports doing routing each with a different ip towards other router in the same subnet (also with ethernet links)

In this case, how do i can forward from a vlan to a specified routing port ?

Regards

[Predrag Jovic]

Yes, it is possible.

You need to enable routing:

      ip routing

To create routed port issue (assign IP address to port):

      interface Gi1/0/x

         no switchport

         ip address 10.10.10.1 255.255.255.252

There is nothing special that should be configured for routing (just routes to specific destinations with next hop should be placed in routing table). Also, the same goal can be achieved by creating "point-to-point" VLANs without configuring routed ports.

For example configuring static default route (forward traffic through Gi1/0/x)

         ip route 0.0.0.0 0.0.0.0 10.10.10.2

[Joseph W. Doherty]

Just to add to Predrag's info, the VLANs would require gateways for routing, which on a L3 switch are normally provided by SVIs. This allows routing to/from other SVIs and/or routed ports.