VTP version mismatch

[abdulmajeed]

Hi all,

I have a cisco 6006 switch with vtp version 2 as vtp server. Now, I have to connect a cisco 1900 series switch to a cisco 2950 switch which is vtp client thro a trunk port. I have to configure the ciso 1900 series switch as vtp client. The problem I am facing is that the version of VTP supported by cisco 1900 series switch is 1 whereas version in cisco 2950 and 6006 are version 2.

Is it possible to make the swithces to communicate in a single vtp domain.

Is there any other option available to include cisco 1900 series switch in the LAN with vlan availability.

Is it possible to upgrade the version of vtp in cisco 1900 series switch.

Thanks in advance.

[milan.kulik]

Hi,

AFAIK, Cat6006 and 2950 support VTP ver 2, but it's disabled by default.

You check it with sh vtp domain (CatOS command), look at the V2 mode column.

If you want to use V2, enable it on a VTP server and the change will be propagated to the whole network.

I'm not using 1900s in my network but I'm afraid they dont support V2.

So my recommendation is to use V1 in the whole network.

If you have to use V2 on your 6006s and 2950s for some reason, there are two possibilities:

a) using two VTP domains. You can put 1900s to another domain. But the new VTP domain with not be contiguous (unless there is a direct trunk connection between all 1900s).

b) make 1900 VTP transparent. You will have to configure VLAN database on each 1900 manually.

You still should be able to run trunks between 1900 and the 2950s. But in both a) and b) cases you need to set the trunk mode to nonegotiate.

Read http://www.cisco.com/warp/customer/473/21.html

for VTP details.

Regards,

Milan

[abdulmajeed]

Hi milan,

I found that the v2 mode in sh vtp domain command is disabled but the version shows 2. Is it means that the switch is capable of vtp version 2 but version 2 is disabled. If it is so, then the version between the cisco 6006 and cisco 1900 series switches are the same. Then what could be the reason for the not transferring of vlan information from the vtp server (cisco 6006) to the cisco 1900 switch. When I check the statistics of vtp in cisco 1900 switch, I found that the Receive summary adverts, receive subset advert and transmit advert requests are incrementing but the receive advert requests, transmit summary adverts and transmit subset adverts are not. When I check for the vtp statistics in cisco 6006 switch, I found that the trunkframesTx and TrunkframesRx are incrementing. So, it is confirmed that the traffic is flowing between the two switches but the vlan information is not read by the cisco 1900 series switch.

Kindly give me suggestions.

[kkalaycioglu]

VTP domain name configured same on all this switches? Or any VTP authentication passwords?

[milan.kulik]

I'd also doublecheck the VTP mode on 1900 (should be client) and trunk configuration on both sides (sometimes nonegotiation is necessary when using old IOS/CatOS).

I usually takes about 5 minutes for VLAN database to get synchronized.

Regards,

Milan

[abdulmajeed]

Hi guys,

I have found that the vtp domain name is same on both sides. The trunk is configured with mode 'ON' on both sides and type 'ISL' on the cisco 6006 side. Cisco 1900 series switch is configured as VTP client. I have done the configuration some 6 hours before.

Thanks in advance,

[milan.kulik]

Hi,

I'd try trunk mode "nonegotiate" on 6006 side.

I don't know the exact command on 1900, but you should turn off the trunk negotiation, too.

On 2900XL it would be "switchport mode trunk" interface command.

Regards,

Milan

[abdulmajeed]

Hi milan,

I have even tried with the "nonegotiate" settings, still I am unable to solve the crisis.

Thanks

[#9]

I experienced a similar problem with Cisco5500 connecting via 100MB fiber ports to Cisco1900. I was unable to upgrade the VTP version on the 1900 to version 2. So I established a trunk with settings "ON" and encapsulation "ISL" from the 5500 to the 1900s. I set the VTP setting on the 1900s to "transparent" while the VTP setting on the 5500 was "client" (the 5500 gets its VTP information a trunked interface from our core 6509 which acts as the VTP server). Because you don't want to have a Version 1 switch broadcasting into your Version 2 VTP domain, the 1900s VTP are set to "Transparent".I then manually pruned the ISL trunks to the 1900s to pass only network and management VLAN traffic to the appropriate 1900. The last thing you will have to do is to create both the user and network VLANs manually on the 1900s and assign the user VLAN to the ports on the 1900 that are being utilized. Set the management VLAN with a management IP address and set the default gateway of the 1900 to the user VLAN gateway. Everything has been working great with no user complaints. Hope this helps.