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VLANs in a network

Unanswered Question
Apr 5th, 2006
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We have multiple switches in our network comprising of 2900,3500 series. The 2900 series supports only 64 VLANs whereas 3500series supports 250 VLANs. VTP is enabled in the network and one of the 3500 is acting as the VTP server .

Now we have 60 VLANs in the network and now we have requirement of another 10VLANs. When we add more VLANs the 2900 series VTP status changess from client to Transperant mode.

Can we restrict some of the VLANs to flow in the 2900 series switches to overcome the problem.

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ankurbhasin Wed, 04/05/2006 - 03:07
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Hi Vivek,

Thats the normal behavior and I do not think you can restrict this in VTP updates.

But can you confirm if the switch your are running in 2900Xl or 2950.

If it is 2950 switch I think it is running a SI Image.Catalyst 2950 switches that run the standard software image (SI) support 64 VLANs; Catalyst 2950 and Catalyst 2955 switches that run the enhanced software image (EI) support 250 VLANs.

So I think if it is 2950 switch you can upgrade it to EI and that should resolve the issue.

HTH, if yes please rate the post.


Mohamed Sobair Wed, 04/05/2006 - 03:16
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Hi vivek,

In additoin to Ankur's post, I would say the following since Ankur has more experience and details on the mentioned aspect but I have faced the same problem before, I am afraid to say there is no way as per my trials before to upgrade the Standard image to Enhanced image on 2950 switches since it comes as standard box without upgrade capabilities.


mbalasko Mon, 04/17/2006 - 12:44
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Are you carrying all the trunks on each switch? Have you thought of clearing uneeded vlans off of the switches and only allowing those that are required to pass?

Use the switchport allowed trunk vlan command to restrict the number of vlans the switch sees.

If this post helps please rate it. Thanks!

vivek_mohta Mon, 04/17/2006 - 19:50
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Yes I am carrying all the trunks on each switch presently and want to restrict unwanted vlan to flwo in some switches. However, I had already tried the command switchport allowed trunk vlan which didnt help me to sort out the problem.

Anonymous (not verified) Mon, 04/17/2006 - 18:33
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