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New Member

Catalyst 3550 Series; L2 or L3?

Hi guys,

I'm not too sure but I have a 48-port Catalyst 3550 Series switch and I need to know if this switch is a Layer 3 switch?

When I do a sh ver, one of the things it says is "Running Layer2/3 Switching Image"

thanks in advance

  • LAN Switching and Routing

Re: Catalyst 3550 Series; L2 or L3?

yes, it's a layer 3 switch. by default though, routing is not enabled.

you can turn it on with the 'ip routing' command. also, there are two different image versions, standard and enhanced. both do routing.

more info here:

New Member

Re: Catalyst 3550 Series; L2 or L3?

I was just reading that. So by enable the "ip routing" I will be basically enabling routing within this switch?

I want to make sure because I will be putting 10 networks in this switch and once I VLAN each of these networks, I want this 3550 to be the default gateway in each of those VLANs.

Let me know if I will be able to accomplish this with this switch?


Hall of Fame Super Blue

Re: Catalyst 3550 Series; L2 or L3?

Yes you can do this. The 3550 will route between the vlans because they are directly connected.


Re: Catalyst 3550 Series; L2 or L3?

Yes you will be able to accomplish that with your switch. Just create your interface vlans, enable ip routing as the above poster said and then assign your ports to the correct access vlan id. Here is a basic link on the 3550 administration guide.

New Member

Re: Catalyst 3550 Series; L2 or L3?

good, so I will just setup each VLAN, give them their IP address and then use this IP as the default gateway for all hosts which will belong to those vlans, right?


Re: Catalyst 3550 Series; L2 or L3?

That's correct.

New Member

Re: Catalyst 3550 Series; L2 or L3?

you're the greatest.... thank you for the confirmation... I always try to be 300% sure when dealing with cisco as it is quite a big area

I will go ahead and deploy this 3550 switch with all the inter-vlan routing. This is good news as it will free up like 6 physical interfaces that I was using out of my router in order to have routing from all my vlans in 2 2950 switches.

thanks a lot

New Member

Re: Catalyst 3550 Series; L2 or L3?


According to my knowledge, usually a 3550 comes in the 'core' layer of the three layer designing model (access layer, distribution layer & core layer) that Cisco describes.

In that it normally says that you fix 2950 switches at Access layer, because it is to access layer that the users connect to.

Then at distribution layer you fix the routers, where inter branch and inter VLAN communication happens at this layer.

Then finally it says at core layer you fix a multi layer (layer 3) switch. The core layer connects to the backbone. A packet goes to the core layer means that it has to go out of the network to the public network.

My question is, if we use a 3550 at the core layer as a L3 switch, how can we connect a leased line or any other WAN connection, I mean to which ports of the switch can we connect them to?

Thanks in advance!

Hall of Fame Super Silver

Re: Catalyst 3550 Series; L2 or L3?


If you think of WAN in terms of leased line then the 3550 does not have an interface that connects to leased line. In that case perhaps the 3550 as the core switch is doing inter vlan routing and could be connected to some router for WAN routing.

And in many networks these days a WAN connection may come on an Ethernet interface, such as DSL or cable modem connections or Metro Ethernet connections. In that case the 3550 could provide connectivity to the WAN without needing any other device.



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