Connecting 3 Distinct LANS

[jinkazama_2]

Another question! :) ... bare with me while i learn!

I need to connect 3 distinint LANS's (i.e on seperate Subnets, in 1 building with about 5 users per segment). They need layer 3 functionality.

The two choices I see are a L3 switch, or a router.

For the purpose of only 5 users i would have thought a 2800 router which comes with 2 onboard LAN ports. (I assume you can route packets coming into these?)

Now I need another module, do the Etherswitch modules route packets, or just switch them? What module could I use to get a 3rd port of ethernet on the switch?

Many thanks

Omid

[paddyxdoyle]

Hi,

I would probably go with a layer 3 switch, such as a 3550 or a 3750, this way you don't have to worry about purchasing different modules for your router as you may in the future need two interfaces on your router for internet or LAN extension connectity plus i think these switches will operate faster than a router.

If you are being forced down the router route called router on a stick, you could get away with only using one interface on your router and configuring dot1q trunking.

So basically the switch port connecting to the router would be configured as a trunk allowing your three VLANs to be tagged, plus the router interface would also be configured as a trunk using subinterfaces, one for each VLAN. You could probably get away with using a smaller router for this purpose but make sure the FE interface supports dot1q trunking first.

HTH

Paddy

[jrahm]

You've probably already made your decision, but I thought I'd address your question anyway. The EtherSwitch module is simply a switch, available in 4 and 9 port configuration. The etherswitch is capable of 15 configurable VLAN's, so you could define your vlan's on your switch ports (802.1q also if necessary) and then define your layer three interfaces:

interface vlan 10

ip address x.x.x.x y.y.y.y

interface vlan 11

ip address x.x.x.x y.y.y.y

interface vlan 12

ip address x.x.x.x y.y.y.y

All routing takes place in the routing hardware, not the EtherSwitch.