Vlans number limitation on C6500 or C3750?

parisdooz12 · ‎08-02-2012

Hi,

our datacenter use C6500 as core chassis. Vlans are propagated by VTP to access switches, which are C3750.

I would like to make vlans provisioning on the C6500, something like 2000 vlans.

Are you aware about limitations for these 2 equipments?

I know that it can be problematic with STP, but spanning-tree "extended-id" is enabled, and we use MST.

One thing starngs is the sh VTP status output (on C6500 & C3750), which indicate a max vlan supportes locally: 1005

S1#sh vtp status

VTP Version : 3 (capable)

Configuration Revision : 350

Maximum VLANs supported locally : 1005

Number of existing VLANs : 250

VTP Operating Mode : Server

Does it mean can't create no more 1005 on my equipments?

Thanks.

P.

Sandeep Choudhary · ‎08-02-2012

If you want to configure vlans above 1006, then try adding

vlan internal allocation policy ascending
You have to reboot the switch for this to take effect and you should be using VTP version 3 on the catalyst.
 
 
Regards
Please rate if it helps.

parisdooz12 · ‎08-02-2012

This command is only use to indicate the switch to borrow internal vlans id from 1006. What I want to know is if I can create 2000 vlan with my design (C6500 with VTP server, C3750 as VTP client, and MST used as spanning-tree protocol)

Giuseppe Larosa · ‎08-02-2012

Hello Parisdooz12,

there are protocol limitations and platform limitations

historically VTP supported only vlans in normal range 1-1005 anf for creating and using vlans in extended range 1006-4094 the switch should have been in VTP transparent mode.

VTPv3 should allow for support of vlans in extended range as declared in VTPv3 doc

http://www.cisco.com/en/US/prod/collateral/switches/ps5718/ps708/solution_guide_c78_508010.html

However, there are also platform limitations and for C3750 the limit should be 1000.and not 4000.

4000 vlans should be supported on C6500 only ( and Nexus and may be C4948- C4500)

I'm afraid you will not be able to have 2,000 Vlans advertised in VTP to a C3750, the switch should revert to transparent mode when reaching its own limit to protect itself.

I have seen this happening in the past with low end switches

Hope to help

Giuseppe

parisdooz12 · ‎08-02-2012

Hi Giuseppe,

thanks for information.

I tried to find information about C3750 limitations but don't find. Do you have a document reference which give this information?

Regards,

P.

Giuseppe Larosa · ‎08-03-2012

Hello Paris,

the C3750 datasheet

http://www.cisco.com/en/US/prod/collateral/switches/ps5718/ps5023/product_data_sheet0900aecd80371991.html

• Up to 1005 VLANs per switch or stack and up to 128 spanning-tree instances per switch are supported.

• 4000 VLAN IDs are supported.

It should mean support for 1000 Vlans taken from the IEEE 802.1Q standard range 1-4094

Hope to help

Giuseppe

parisdooz12 · ‎08-03-2012

Hi Giuseppe,

ok, thanks. Actually, VTP will be ok in my case with C3750 as my principal concern was to use vlan id > 1005 with VTP, but keeping number of vlan <1000.

Beside that, I noticed to that VTP v3 is avaiblable on C3750 only in 12.2(52) IOS version, which make older versions unable to make VTP with vlan ID > 1005.

Best regards

P

Jigar Dave · ‎08-03-2012

For 6500 Chassis, you can create 4094 VLANs. its limitation.

make sure that you will use high number vlans for L3 connection between 6500 chassis, like between 4000 to 4094

3000 range, you can use for distribution layer

start from lower range vlan (less than 1000) for access layer switches because high number vlans are supported on 65K but not on L2 access switches.like 2950,2960.

not sure abt what vlans supported for 3500 and 3700 family of Cisco.

hope this helps, rate helpful posts.

Thanks,

Jigar