Proper interface configuration cisco routing

Posted on 2004-10-20
Last Modified: 2010-04-17
I have a cisco router with 1 fast ethernet interface.

I then have that interface goto a switch, which connects to our bgp peer uplinks.

The question is as follows:

Do I 1. create sub interfaces on the cisco router, or 2. create secondary addresses to connect to the other subnets?

I'm pretty sure that you only want to use sub interfaces with vlan'ing, but I wanted to double check.

Question by:sasecool
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lrmoore earned 250 total points
ID: 12360987
you can only use subinterfaces when using vlan trunking to the switch.

Secondaries are not usually advised, unless you have no choice. In your case, that may be what you need to do.
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Expert Comment

ID: 12364570
A trunk with subinterfaces sounds like the right solution to me.  Each peer is on its own network range, right?

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Any progress? Are you still working on this? Do you need more information?

Author Comment

ID: 12404504

to clarrify, no ip address has to be set on the interface to utilize the vlan features of the sub interfaces, correct?


... This solution works, but I would rather utilize the subinterfaces, however, the switch connected to the router does not support vlan trunking.

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