Sorry this is long but please read.

I just started configuring switches last week in place of my colleague who is ill in hospital and won't be back to early Jan. Anyway I'm learning quickly. Which is good because I'm studying for my CCNA.

I was given the task of setting up a Vlan on a 3550 switch for our training room. The thing was I had to pull the existing 2948G switch out and use its settings and put them on the new 3550. The old one used a Bridge group but I figured that I have its IP so I could work it out.

Anyway just to make sure I got the config from another 3550(setup by my colleague) switch in the room which used Vlan 34. I noticed that all the ports were configured to use Vlan 1 which is the default but it uses the correct IP for Vlan 34, so you have the following:

Vlan 1 (10.96.34.135/25) --> all port interfaces. ie 34 is for Vlan 34 on our network.

So with the new 3550 I said ok I will just leave all the ports on the deafult Vlan 1 and assign it the IP 10.96.32.6/25 which is what the 2948G BVI 32 used.

Ok everything seemed fine. But I began thinking that both shouldn't be assigned to Vlan 1 so i tried to rechange the IP on vlan 1 for this second 3550 switch and create a Vlan 32 and assign the IP from above. I couldn't do it because it kept saying 10.96.32.0 is already assigned to vlan 1 even though I had changed the IP on Vlan 1 to somehing else.

Anyway in the end I just left it all to Vlan 1 and everything seems ok, but how can I remove the IP on Vlan 1 and set it up on the new Vlan 32. Or is ok to leave it on the defaults for both switches. I'm thinking that it doesn't matter because the IP's are different and Vlan 1 is just used locally by the switch not globally. Please someone give me some advice?

Last edited by nero64 on 12-26-04 at 05:38 AM

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I'm not exactly sure what you have going but no you need to assign each port to a particular VLAN. Are you trunking? If so then you need to make sure trunking is enabled on this new switch and using the correct encapsulation (ISL) and if you have a switch serving this domain which is a Server then you should configure that switch to be a client. You shouldn't really have problems once your trunking is set up correctly and you assign each port to the right VLAN.
-neural

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Hi,

All ports on each switch are assigned to the Vlan 1 which use different IP's for each switch.

The switches are cascaded off a floor switch which goes to the core switch. I'm not sure if trunking is enabled. One switch has the spanning tree portfast on each port.

I don't want to be implementing trunking if it may backfire somewhere on the network.

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What do you mean ip address different on each switch? If you aren't using trunking then you really aren't using the VLAN as its intended. Without trunking they are just disparate switches, you only get some benefit locally per switch.
-neural

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They're not trunked, so everything should be fine.

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