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

Welcome to Cisco Support Community. We would love to have your feedback.

For an introduction to the new site, click here. And see here for current known issues.

New Member

Two LAN Segments

I have a 2620 router with single ethernet interface. I want to connect two different LAN segments to this router. How to do this ? Can anyone help me?


Re: Two LAN Segments

You basically set up a VLAN trunk port on the switch, and configure the single interface on your 2620 router to provide interVLAN routing via LAN sub-interfaces. How you do it depends on what kind of switch you are connecting the router to, either a switch running Cisco IOS or a switch running Cisco Catalyst OS. Here's two links:

Configuring InterVLAN Routing and ISL/802.1Q Trunking on a Catalyst 2900XL/3500XL/2950 Switch Using An External Router

Configuring ISL and 802.1q Trunking Between a CatOS Switch and an External Router (InterVLAN Routing)

Please note, to create and use sub-interfaces on a router such as the 2620, you will need a "Plus" version of IOS. And to be able to run "Plus" software, you may need more DRAM and flash memory.

Hope this helps.


Re: Two LAN Segments

I believe you can also use the keyword "Secondary" to add additional addresses to a single interface.

Use the same syntax for ip addr on the appropriate interface, adding the word "secondary" (no quotes) to the end.

Not a good way to set it up (multinetting an interface) but sometime you gotta do what you gotta do. If you were planning on using this router for a firewall, don't use this for a firewall ... your system is exposed.

Good Luck


CreatePlease login to create content