Defining VLANs?

[Armegeden]

Ok...

I have a Cat4000 with 27 Vlans defined and is in VTP Server mode. Currently on Rev.112.

I found another Cat4000 in another building also with 27 defined Vlans in the "sh run". This device is in VTP Client mode, though, and also has Rev.112.

Now, isn't that redundant? Defining the same exact Vlans on a Client switch when it is getting updates from a VTP Server? Could I just remove all the Vlans defined in the Client's running-config and have it just get the info off the Rev.?

Thanx for any help...

[glen.grant]

What you are seeing on the 4000 was sent by the server , it was not defined at the 4000 switch. Do not remove anything on the 4000 . All vlans are created on the server . You cannot "create" vlans on a client. That is basically the client server model allows you to create all vlans on 1 switch (server) and then determine what is allowed down to every switch from 1 place .

[Armegeden]

If the VLANs that are listed in the Client (mhg) come from the Server (21cc1), then something is amiss. The VLANs that are listed via "sh run" on MHG are not identical to those listed from "sh run" on 12CC1.

I'll attach the running-config portion of the two if that'll help...

I really don't know what's going on, hah

[thisisshanky]

Armegeden,

It looks like both switches were setup in HSRP (with the 4006 L3 being active). I see that a few vlans are out of sync (22,24 25). To figure out which is the VTP server and which is the client,

please paste sh vtp status from either switches.

[Armegeden]

21CC1#sh vtp status

VTP Version : 2

Configuration Revision : 112

Maximum VLANs supported locally : 1005

Number of existing VLANs : 27

VTP Operating Mode : Server

VTP Domain Name : IM

VTP Pruning Mode : Disabled

VTP V2 Mode : Disabled

VTP Traps Generation : Disabled

MD5 digest : 0x93 0x60 0xA4 0x47 0x94 0x82 0xBF 0xE2

Configuration last modified by 192.168.26.1 at 4-7-05 04:43:33

Local updater ID is 172.16.208.110 on interface Vl1 (lowest numbered VLAN interface found)

21CC1#

and

MHG#sh vtp status

VTP Version : 2

Configuration Revision : 112

Maximum VLANs supported locally : 1005

Number of existing VLANs : 27

VTP Operating Mode : Client

VTP Domain Name : IM

VTP Pruning Mode : Disabled

VTP V2 Mode : Disabled

VTP Traps Generation : Disabled

MD5 digest : 0x93 0x60 0xA4 0x47 0x94 0x82 0xBF 0xE2

Configuration last modified by 192.168.26.1 at 4-7-05 04:43:33

MHG#

The 21CC1 is definately the Server, but why isn't the MHG's Vlan list being overwritten by the Servers updates? Weird...

[thisisshanky]

Can you also paste a sh vlan output from both switches ?h

[Armegeden]

Figured I'd attach to save from scrolling 8)

[thisisshanky]

Clearly both the vlan databases (sh vlan output) seems to be synced properly. The interface vlan command is used to create a layer 3 interface for each vlan.

VTP doesnt control these layer 3 SVI interface configurations on each switch that is part of a VTP domain. These interfaces are manually created by the person configuring the switch.

For ex: int vlan 22 shows up on the 4000 switch but not on the 4503. This could be either because the interface vlan 22 was never created on the 4503 or the configs could have got lost, because it wasnt saved to memory and the switch was powercycled.

You can simply create this SVI interface on the 4503 by using command,

int vlan 22

standby ip <>

..

..

or to remove the vlan use command,

no int vlan 22

HTH

[Armegeden]

Great, that all makes sense and I thank you for the input.

Now from a logic perspective; If the 4000 is a VTP Client and is getting the governing VLAN info from the 4503 VTP Server, isn't defining all those VLANs via the "interface vlan" command pointless? aren't they overwritten by the VTP Server?

Should I just "no int vlan" the created interfaces on the 4000?

[thisisshanky · Accepted solution]

It is kind of pointless to have those interface vlan definitions on the 4503, if the same defintion is not there on the 4000. (Also because there are standby (hsrp) commands under the vlan interfaces, it makes sense to have the interfaces defined on both switches)

Make sure that you dont have any devices on the 4000/4503 on those vlans, before you remove those vlan interfaces.