Maximum number of vlans supported in cisco switches

[abdulmajeed]

Hi,

Let me know the maximum number of vlans and STP instances that can be allowed to run in cisco 6006, 4006,3548 and 2950 switches. Kindly send me documents regarding the same.

Thanks in advance,

[raju]

Hi ,

Check this out...

http://www.cisco.com/en/US/products/hw/switches/index.html

[skarundi]

In general the "Configuring Vlan" section in each product documentation will usually list the number of vlans a switch can support.

I have included the link to this section for each of the products you have listed

Catalyst 6500

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URL:http://www.cisco.com/univercd/cc/td/doc/product/lan/cat6000/sw_7_6/confg_gd/vlans.htm#1086514

Catalyst 4000

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URL: http://www.cisco.com/univercd/cc/td/doc/product/lan/cat4000/rel7_6/config/vlans.htm#1032203

Catalyst 3548XL

---------------

http://www.cisco.com/univercd/cc/td/doc/product/lan/c2900xl/29_35wc6/scg/swvlan.htm#xtocid1

Catalyst 2950

------------

http://www.cisco.com/univercd/cc/td/doc/product/lan/cat2950/12119ea1/2950scg/swvlan.htm#1353846

[abdulmajeed]

Hi,

Thanks for your information.

It is confirmed from the documents that cisco 6006 and cisco 4006 will support 4096 vlans whereas cisco 2950 and 3548 will support 250 vlans with max 64 STP instances. I am having a plan of increasing my no of vlans from 48 to 60 in cisco 6006 Switch(VTP server). I had cisco 3548 and 2950 switches as my VTP clients. With spanning tree in PVST+ mode, there will be a STP instance running for each vlan. Will the switches are able to handle 60 STP instances. Shall I go along with my configuration change. what will be the impact in the network.

It is very urgent. Suggestions please.

[Georg Pauwen · Accepted solution]

Hello Abdul,

running 60 spanning tree instances in your network should be no problem. Just be aware that if you are planning on using more than 64, a maximum of 64 spanning-tree instances are supported in VTP. If more VLANs are defined in the VLAN Trunking Protocol (VTP) than STP instances, you can enable STP on only 64 VLANs. The remaining VLANs operate with STP disabled.

Regards,

Georg

[abdulmajeed]

Dear Georg,

Thanks for your kind information.

Regards,

Majeed.

[milan.kulik]

Georg,

I agree, but to be exact:

64 spanning-tree instances is not a VTP limit, it's just a Cat3500XL and 2950 PVST+ implementation limit.

There is also one troublesome aspect:

When adding 65th VLAN, it might be running an STP instance, but one of the previously configured VLANs might disable STP.

I strongly don't recommend running any VLAN without STP. It's very dangerous and STP loops might break your network down.

Regards,

Milan