vlan not coming up...

[gauravm]

i have created 2 vlans (VLAN 6 and VLAN7)in my Switch (Switch1).

one of port is configured for vlan 6 (connected to switch2).

i want to pass on the vlan 3 info also on to the other users on switch2.

interface GigabitEthernet3/5

switchport access vlan 6

switchport trunk allowed vlan 6,7

but it says Vlan7 is up, line protocol is down. but, vlan 6 is up.

kindly help...

[ankurbhasin]

Hi Quaravm,

Here you go with the answer and the solution...

Create trunk first. Currently your gig3/4 is a access port with vlan 6 configured on it. Make it trunk first and it will resolve you issue. Remember to bring any vlan up switch should have some port assigned to that vlan or there should be a trunk port and that vlan should be allowed on it.

You have just created the vlans but for vlan to be active some ports need to be assigned to that vlan or either there should be a trunk and that vlan should be allowed.

I am sure currently you do not have any ports assigned to vlan 7 and because you have connected the 2 switches with vlan 6 on it that is the reason vlan 6 is up.

First create the trunk between the 2 switches and once trunk is up vlan 7 will also be up and later you can restrict only vlan 6 and vlan 7 on the trunk.

Make sure you craete the trunk first.

switchport trunk encapsulation dot1q

switchport mode trunk

HTH

Ankur

[gauravm]

thanks ankur.

i have done that and vlan 7 starting working.

but the problem now is that vlan 6 has gone down.

ankur , tell me do i have to configure trunk on other switch also . actually i have 5505 with me on the other end but the port capabilities says it is not enabled for trunk.

cant make out what to do ... ??help!!!

[ankurbhasin]

Hi Gaurav,

You are right you have to configure trunk on both the switches to bring the trunk up as well as all the vlan up

Cat5505 can sure be configured as a trunk port.

set trunk mod_num/port_num on dot1q

Also ypu can check with s"sh port capabilities" that switch port on cat5k switch is capable of dot1q trunking or not.

Can you try this command also which switch you have on other end can you post me the config of the interface.

Regards,

Ankur

[glen.grant]

Ok it sounds like you have an IOS switch . You are not creating the vlans correctly . It sounds like you are creating the layer 3 SVI for managing the switch of which you can only have 1 active which is why one keeps going down . You must create the layer 2 vlan . If you do a "show vlan " do all 3 vlans show active " or do they show up at all ? To create the layer 2 vlans , conf t , vlan x , enter . this will create the layer 2 vlan . Once you get all your vlans to show active with the "show vlan" command you can then try to trunk them. I am surmising you are trying to create the vlan by doing " conf t, interface vlan x. This is incorrect unless you are trying to create a single layer 3 SVI to manage the switch with .

As far as the 5505 if you do a show port capabilties and the port does not say it will support ISL or dot1Q you are out of luck , some older 5500 cards did not support trunking .

[Richard Burts]

Gaurav

I am not sure that I fully understand your question. You start by talking about vlan 6 and 7 but then there is also a vlan 3. Perhaps you can clarify your situation and we might be able to provide better help?

One important question to start: is there at least one port in vlan 7 that is connected to an active device? On many Catalyst switches a vlan will not be protocol up until there is at least one active connection.

HTH

Rick