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VLAN not working

londint
Level 1
Level 1

I have set up 2 new vlans on a new switch e.g vlan 1 and vlan 900. I have given them addresses

vlan 1 - 20.30.50.1/24

vlan 10 - 30.40.50.1/24

But VLAN 1 keeps going up and down. How can I go about rectifying this?

In addition, this new switch (Cat 2950) is connected to another switch (Cat 3550) via their FA0/1 interface, which I have put in vlan 1. And on the 3640 I have existing vlans and have configured the Cat 2950 to be a client to the Cat 3550 but they are both at configuration revision 0 with the same VTP domain.

Unfortunately the Cat 2950 is not picking up the VLAN information from the Cat 3550. So I am not able to put any of the interfaces on the 2950 in any VLAN. How can I go about rectifying this?

8 Replies 8

bpotschien
Level 1
Level 1

Do you have a layer-3 module on your 3550 or a seperate router for routing through vlans?

Check the vlan trunk between your switches.

Does the 2950 see no vlans? (#show vlan)

Thanks yes I do.

I am not truning between the Int fa0/1 of the 2 switches. Do I need to do this.

Yes, you should do it, when you have more than one vlans on both switches. I'am assuming that you want connect the vlans together.

You can read my other posting.

Regards

Peter

pflunkert
Level 4
Level 4

Hi,

first you must configure layer 2 vlans:

conf t

vlan 2

name xyz

vlan 3

name vlan 3

Then (or as first step) configure the vtp domain

conf t

vtp domain test

vtp mode server (default)

Connect the switch to the second switch as trunk

conf t

int fast 0/24 (for example)

switchport mode trunk

switchport trunk encapsulation dot1q

On the second switch configure this:

conf t

int fast 0/24 (for example)

switchport mode trunk

switchport trunk encapsulation dot1q

exit

vtp mode client

vtp domain test

Now the links should up and you receive the vlan information. When you had problems, check your trunk configuration. Now you have a layer 2 configuration.

You can add the layer 3 interface as you want.

conf t

int vlan 2

ip address xxxxxxx

and so on

The layer 3 interface is only up, when you a existing layer 2 port (this could also be a trunk interface).

Regards

Peter

aashish.c
Level 4
Level 4

Hi

check if you have assigned an ports to Vlan1 or not.

Only 1 vlan can be active on 2950, means 1 can be the management vlan on this switch.

as fas as VTP is concerened, check the domain name, password(if assigned), make sure links between switches are trunk links NOT access.

check the VTP mode on all the switch. By default switches stay in VTP server mode.

Vlan 1 is by default created on all the switches, so u can assign ports to vlan 1.

but other vlans should be automatically created on VTP clinet switches if u create a vlan on VTP server.

if it doesnt work, paste the configs of swtch and "sh vtp stats"

regards

aashish C

Thanks

The Cat 2950 is a Cat 2950xl

Sh vtp sta

VTP Version : 2

Configuration Revision : 0

Maximum VLANs supported locally : 68

Number of existing VLANs : 5

VTP Operating Mode : Client

VTP Domain Name : Cxxxxx

VTP Pruning Mode : Disabled

VTP V2 Mode : Disabled

VTP Traps Generation : Disabled

MD5 digest : 0xDF 0xD1 0x01 0xC6 0x55 0xB6 0x84 0x84

Configuration last modified by 20.x.x.x at 6-4-93 08:19:01

Local updater ID is x.x.x.x on interface Vl1 (lowest numbered VLAN interface f

ound)

On the Cat 3550, it is

VTP Version : 2

Configuration Revision : 0

Maximum VLANs supported locally : 1005

Number of existing VLANs : 7

VTP Operating Mode : Server

VTP Domain Name : Cxxxxx

VTP Pruning Mode : Disabled

VTP V2 Mode : Disabled

VTP Traps Generation : Disabled

MD5 digest : 0xDF 0xD1 0x01 0xC6 0x55 0xB6 0x84 0x84

Configuration last modified by 1.20.x.x at 6-4-93 08:19:01

Local updater ID is x.x.x.x on interface Vl1 (lowest numbered VLAN interface f

ound)

As at now, I have configured the following

On the Cat 3550

interface FastEthernet0/48

switchport trunk encapsulation dot1q

switchport mode trunk

no ip address

On the Cat 2950

interface FastEthernet0/24

switchport trunk encapsulation dot1q

switchport mode trunk

no ip address

Thanks

Hi,

thanx for updating. the config and stats seems to be fine except that Config. revision number is 0 on both switches.

convert the VTP mode of 2950 to transparent, save the changes and then again to client and same parameters as on server.this will take the VTP to factory default settings.

Then create 2-3 dummy vlans on 3550 for testing in vlan database and check whether the changes are downloading on 2950 or not.

also on 2950remove all the created vlans except 1 and othe default vlans. Let 2950 download thse vlans from 3550.

regards

aashish C

Thank you so very much.

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