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New Member

why my VTP client switch changes automatically to vtp transparent?

hi ppl!

i got a severe problem in my network. currently, we are implementing cisco 5509 catos based layer switch as our vtp mode server. so when i tried to hook up a new cisco 2950 switch by configuring it as vtp client with the same vtp domain name with dat of cisco 5509 vtp server mode, it will automatically change to vtp transparent mode but with the same vtp domain name. so, is there anyone dat can give me the best solution to mitigate my problem. e-mail me via dawit_a3@yahoo.com

dawit [B.Sc,CCNA,CCNP], Ethiopia

thanx

8 REPLIES
Silver

Re: why my VTP client switch changes automatically to vtp transp

Hello,

I have never heard of a switch changing VTP mode *automatically*.

Did you create a VLAN with a value greater then 1005 on the Catalyst 2950 switch beforehand?

It is not possible to create VLANs while the switch is in VTP client mode. Post your configuration and software version and I'll see what I can do.

HTH

--Leon

* Please rate posts.

New Member

Re: why my VTP client switch changes automatically to vtp transp

here is the configuration as per your request

version 12.1

service nagle

no service pad

service timestamps debug uptime

service timestamps log uptime

service password-encryption

service linenumber

!

hostname ccr6switch1

!

logging monitor notifications

aaa new-model

aaa authentication login default local

ip subnet-zero

no ip source-route

no ip gratuitous-arps

ip domain-name netdev.aau.edu.et

ip name-server 10.6.10.22

ip name-server 10.5.10.22

ip name-server 10.4.10.22

ip dhcp-server 10.6.10.100

vtp domain aau

vtp mode transparent

!

vlan 6

name 4kthin

said 10006

!

vlan 7

name 5kthin

said 10007

!

vlan 8

name thinclient

said 10008

!

vlan 9

name Multi

said 10009

!

vlan 10

name SSserverFarm

!

vlan 13

name ccr6_1

!

vlan 14

name ccr6_2

!

vlan 15

name ccr6_3

!

vlan 16

name ies1

!

vlan 17

name ies2

!

vlan 18

name sisa6switch1

!

vlan 19

name bued6switch1

!

vlan 20

name ken6switch1

!

vlan 21

name ken6switch2

!

vlan 22

name law6switch1

!

vlan 23

name reg6switch1

!

vlan 24

name ier6switch1

!

vlan 25

name glib6switch1

!

vlan 26

name idrl6switch1

!

!

!

spanning-tree extend system-id

no spanning-tree vlan 6

no spanning-tree vlan 7

no

no spanning-tree vlan 19

!

!

interface FastEthernet0/1

description from ccr6switch2

switchport trunk allowed vlan 1,11-15,300,301,1001-1005

switchport mode trunk

no ip address

!

!

interface Vlan1

ip address 10.1.0.6 255.255.255.0

no ip redirects

no ip redirects

no ip proxy-arp

no ip route-cache

!

ip default-gateway 10.1.0.2

ip http server

!

^C

AND THE SOFTWARE VERSION IS

IOS (tm) C2950 Software (C2950-I6Q4L2-M), Version 12.1(9)EA1, RELEASE SOFTWARE (

fc1)

Silver

Re: why my VTP client switch changes automatically to vtp transp

Hi,

As by software reference, When the network is configured with more than the maximum 250 VLANs, the switch automatically changes from VTP server or client mode to VTP transparent mode.

An automatic mode change also can occur if the switch receives a VLAN configuration database message that contains more than a set number of VLANs. This will happen in switches when they are connected to a VTP domain that has more VLANs than are supported locally.

http://www.cisco.com/en/US/products/hw/switches/ps628/products_configuration_guide_chapter09186a00801cde85.html

Go thro. the below mentioned link to see the cause and workarounds,

http://www.cisco.com/en/US/tech/tk389/tk689/technologies_tech_note09186a0080094c52.shtml#vtp_mode_change

There is no finding other than this for the mentioned problem. So just try by configuring VLANs lesser than 250 number and tell us still r u facing the same problem???

Rate if it does,

Rgs

New Member

Re: why my VTP client switch changes automatically to vtp transp

hi there

you know what i did all the solutions dat you recommended before i post the problem here in this forum . i did it again and removed all unnecessary vlans from both trunk ends [ cisco 2950 2 switches] but when i do immediately conncet the cat5 cable to the trunk port it will immediatelly change the vtp mode from client to transparent. can u tell me a solution other than the one you mentioned before?

dawit

Re: why my VTP client switch changes automatically to vtp transp

This is happening becasue there is a limit of 64 VLANs on a 2950. Once that limit is reached, the switch goes into VTP transparent to prevent any damage, and to ensure that it continues to propagate the VLANs.

Now, I'm not sure of the next bit, so you will have to try it out ... if I remember rightly, the limit is actually on the number of spanning-tree instances, rather than the VLANs in the domain. So, if you go to your trunks and disallow any VLANs that are not relevant to the switch, then the box will not create any spanning-tree instances for those VLANs. At that point, as long as you do not need the box to participate in more than 64 of the VLANs, it may stay in client mode. But I'm not 100% sure of that. Try it, and let us know if it works.

Kevin Dorrell

Luxembourg

New Member

Re: why my VTP client switch changes automatically to vtp transp

hi kevin ! i do really appreciate your concern to alleviate my problem. you know what i did all the solutions dat you recommended before i post the problem here in this forum . i did it again and removed all unnecessary vlans from both trunk ends [ cisco 2950 2 switches] but when i do immediately conncet the cat5 cable to the trunk port it will immediatelly change the vtp mode from client to transparent. can u tell me a solution other than the one you mentioned before?

dawit

Purple

Re: why my VTP client switch changes automatically to vtp transp

What Kevin recommended should work , I have done it many times . You need to manually prune "both sides " of the trunk link . Manually prune the 5500 side (clear trunk ) and manually prune off the 2950 side (switchport trunk allowed) . This is best practice and should be implemented on all your trunk links not just down to the 2950's . Obviously you probably don't actually need more than probably a handful of vlans on a 2950 so everything else should be manually pruned .You cannot use vtp pruning to cure this situation you must manually prune...

New Member

Re: why my VTP client switch changes automatically to vtp transp

hi

i really thank you foe your comment. foe your info, i have done all what u said but at the end still the vtp mode changes from client transparent!

if u can, will u make it your recommendation more specific and detailed [including the commands]?

thanx

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