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ovm
New Member

Gigabit down when changing to VTP transparent

We have reached the maximum of 64 VLAN in our switch environment 3548 + 6509. To overcome the limit we have decided to change the LAN environment access layer from VTP client to transparent. But when we issue the transparent command the 3548 switch shutdown both gigabit uplinks. This shutdown causes 30sec outage - STP:-(

Is it possible to change to transparent mode without gigabit's are brought down?

Rgds Ole

4 REPLIES
Cisco Employee

Re: Gigabit down when changing to VTP transparent

Why dont you just clear the VLANs on the trunk(on the 6509) which you do not want to pass on to the 3548XL.

ovm
New Member

Re: Gigabit down when changing to VTP transparent

It will not help, as I see it. The 3548 will still receive all VLAN with VTP, and run a STP instances for each VLAN, even the VLAN where no ports is assigned.

Cisco Employee

Re: Gigabit down when changing to VTP transparent

It'll not. Try this on your 6500

clear trunk x/y

Example:clear trunk 2/4 10-100

cs-c4003-47a> (enable) sh spantree 2/4

Port Vlan Port-State Cost Prio Portfast Channel_id

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

2/4 1 forwarding 19 32 disabled 0

2/4 2 forwarding 19 32 disabled 0

2/4 3 forwarding 19 32 disabled 0

2/4 4 forwarding 19 32 disabled 0

2/4 5 forwarding 19 32 disabled 0

2/4 6 forwarding 19 32 disabled 0

2/4 7 forwarding 19 32 disabled 0

2/4 8 forwarding 19 32 disabled 0

2/4 9 forwarding 19 32 disabled 0

cs-c4003-47a> (enable)

As you see all the trunk is forwarding only vlans 1-9

Cisco Employee

Re: Gigabit down when changing to VTP transparent

I forgot to mention this. On the XL, remove the unneccessary VLANs using

switchport trunk allowed vlan remove

Example:switchport trunk allowed vlan remove 10-100

interface FastEthernet0/24

switchport trunk encapsulation dot1q

switchport trunk allowed vlan 1-9,101-1005

switchport mode trunk

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