VLAN problem

[pselva2000]

Hi

we have link problem between 2 buildings that is fibre module is keep flashing green and amber, so we changed fibre moudule patch leads. still problem is not resolved. so to ensure that problem is not with switch, we tried with other switch, we have deleted all existing VLANs and we created vlan 201 for trunking and we made vtp as client mode, after doing this we conncted to main switch, apparently main switch went down and all vlans are over written, usually if vtp mode is in server then it will over write the main switch vlan, am wondering how vlan is over written while it is in edge switch is in client mode. can any one help me on this please.

Thanks

selva

[Ganesh Hariharan · Accepted solution]

Hi
we have link problem
between 2 buildings that is fibre module is keep flashing green and
amber, so we changed fibre moudule patch leads. still problem is not
resolved. so to ensure that problem is not with switch, we tried with
other switch, we have deleted all existing VLANs and we created vlan
201 for trunking and we made vtp as client mode, after doing this we
conncted to main switch, apparently main switch went down and all vlans
are over written, usually if vtp mode is in server then it will over
write the main switch vlan, am wondering how vlan is over written while
it is in edge switch is in client mode. can any one help me on this
please.
Thanks
selva

Hi Selva,

Vlan can be overwrite when it gets message from another vtp server in same domain ,are you sure you are having only one vtp server in your network which went down or you have another also.

Hope to Help !!

Ganesh.H

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[pselva2000]

Yes we have only one VTP domain

. apparenlty this switch was VTP domain before and we changed to client.

is there any thing to do with eigrp, by mistake there was EIGRP in that switch. my

understading is EIGRP is only for Layer3 but VLAN is in layer 2 I don't no how it

affect this

[Ganesh Hariharan · Accepted solution]

Yes we have only one VTP domain
. apparenlty this switch was VTP domain before and we changed to client.
is there any thing to do with eigrp, by mistake there was EIGRP in that switch. my
understading is EIGRP is only for Layer3 but VLAN is in layer 2 I don't no how it
affect this

It's not a problem with EIGRP,both are diiferent protocol what my suspect is some other switch is alos configured as VTP server in your domain.

Ganesh.H

[glen.grant]

   It does not need to be a vtp server to overwrite all the vlan information .  "Any" switch in the same vtp domain whether its a vtp server or a "vtp client" , if it is inserted into the the network with a higher vtp config revision number  than the current the vtp server it will overwrite the existing vtp server . Thats why you always change the client  to a vtp domain name to name other than what is currently used and then change it to the current  vtp domain name , this resets the vtp config revision number to 0 and it cannot overwrite anything then .

[the-lebowski]

I thought there was a big push to move away from VTP because of problems like this?

You could always set your switch to transparent as well, then make sure the revision is lower than your vtp server then change it to client.

[glen.grant]

  There is nothing really wrong with vtp  as long as you understand this ramification when working on client switches .  In large installations where you have a lot of switches and you need the vlans across many different switches it is actually handy and reduces work, you just have to understand that big gottcha when you use it .  Certainly transparent mode eliminates this problem but in big installations it can be a fair amount of extra work.

[pselva2000]

Hi Thanks for all

the problem is fixed, the problem is client version of VTP is higher than VTP domain which over written those VLANs.

[lamav]

VTP is kaka. I would never use it, no matter what. The very small benefit it gives you is grossly outweighed by the disaster it can cause.