Help with learning VTP

Unanswered Question
Sep 10th, 2007

Hi,

I connected a 2950 to a 2924 and set the 2950 to VTP SERVER and the 2924 to VTP CLIENT but the 2924 won't learn the additional VLANs I created on the 2950. I even manually set the VTP DOMAIN on the 2924 to match the 2950 even though I thought that would be one of the things learned through the VTP announcements. Any help would be appreciated. Here's the port configs and some info:

2950

----

interface FastEthernet0/24

switchport mode trunk

speed 100

duplex full

Cat2950A#show int fa0/24 trunk

Port Mode Encapsulation Status Native vlan

Fa0/24 on 802.1q trunking 1

Port Vlans allowed on trunk

Fa0/24 1-4094

Port Vlans allowed and active in management domain

Fa0/24 1

Port Vlans in spanning tree forwarding state and not pruned

Fa0/24 1

2924

----

interface FastEthernet0/22

duplex full

speed 100

switchport trunk encapsulation dot1q

switchport mode trunk

Cat2924A#show int fa0/22 status

Port Name Status Vlan Duplex Speed Type

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

Fa0/22 connected trunk Full 100 100BaseTX/FX

I have this problem too.
0 votes
  • 1
  • 2
  • 3
  • 4
  • 5
Overall Rating: 4 (2 ratings)
Loading.
rileymartin Mon, 09/10/2007 - 16:25

Cat2924A#show vtp status

VTP Version : 2

Configuration Revision : 1

Maximum VLANs supported locally : 68

Number of existing VLANs : 5

VTP Operating Mode : Client

VTP Domain Name : VTP-1

VTP Pruning Mode : Disabled

VTP V2 Mode : Disabled

VTP Traps Generation : Disabled

MD5 digest : 0x3D 0xE8 0xCA 0x71 0x45 0x40 0x32 0xD1

Configuration last modified by 192.168.126.13 at 3-1-93 01:09:25

Cat2924A#show vtp counters

VTP statistics:

Summary advertisements received : 8

Subset advertisements received : 1

Request advertisements received : 0

Summary advertisements transmitted : 14

Subset advertisements transmitted : 0

Request advertisements transmitted : 2

Number of config revision errors : 0

Number of config digest errors : 0

Number of V1 summary errors : 0

VTP pruning statistics:

Trunk Join Transmitted Join Received Summary advts received from

non-pruning-capable device

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

Fa0/22 0 0 0

Cat2950A#show vtp status

VTP Version : 2

Configuration Revision : 1

Maximum VLANs supported locally : 64

Number of existing VLANs : 5

VTP Operating Mode : Server

VTP Domain Name : VTP-1

VTP Pruning Mode : Disabled

VTP V2 Mode : Disabled

VTP Traps Generation : Disabled

MD5 digest : 0x3D 0xE8 0xCA 0x71 0x45 0x40 0x32 0xD1

Configuration last modified by 192.168.126.13 at 3-1-93 01:09:25

Local updater ID is 192.168.126.2 on interface Vl1 (lowest numbered VLAN interfa

ce found)

Cat2950A#show vtp counters

VTP statistics:

Summary advertisements received : 14

Subset advertisements received : 0

Request advertisements received : 1

Summary advertisements transmitted : 12

Subset advertisements transmitted : 1

Request advertisements transmitted : 0

Number of config revision errors : 0

Number of config digest errors : 0

Number of V1 summary errors : 0

VTP pruning statistics:

Trunk Join Transmitted Join Received Summary advts received from

non-pruning-capable device

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

Fa0/24 0 0 0

Cat2950A#

sundar.palaniappan Mon, 09/10/2007 - 18:50

The config revision is the same (1) on both the client and server and that may be the problem here. On the 2924 (client)change the VTP mode to transparent and set it back to client and that should reset the config revision to 0. Alternatively, adding a VLAN on the 2950 switch by going into the VLAN database and exiting should raise the config revision # and should help achieve the same results. Let us know the outcome.

HTH

Sundar

rileymartin Tue, 09/11/2007 - 05:46

I powered off/on the equipment and VTP is working on one of the 2924 switches. It now shows the correct VLANs and configuration revision. On the other switch I forgot to do a 'wr mem' so the trunking settings were missing and it was set to isl which I guess is the default for a 2924 switch. I added the below settings to the interface connecting the switches but after the trunk was established VTP still wasn't working. The interfaces are up and trunking and I can PING and TELNET so connectivity is there.

Interface config on the stubborn 2924

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

interface FastEthernet0/22

duplex full

speed 100

switchport trunk encapsulation dot1q

switchport mode trunk

I then tried adding three more VLANs to the 2950, typing apply after each one, and the one 2924 would get each one but the other 2924 never changed.

I then tried changing the stubborn 2924 to VTP TRANSPARENT and it still didn't work. I made sure to do a 'wr mem' to save the switchport and trunk settings on the interface and powered off/on the 2924 and still no good.

I tried changing the VTP domain on the stubborn 2924 to match what was on the other two switches and then added another vlan on the 2950 but still nothing on the stubborn 2924. I did a reload on the 2924 and again nothing.

Edison Ortiz Mon, 09/10/2007 - 19:18

I don't see a problem here. Both switches have the same amount of Vlans (5).

Can you post the 'show vlan' output from both switches and tell us what Vlans are actually missing on the 2924 ?

rileymartin Tue, 09/11/2007 - 05:13

Thanks everyone for the replies. Here is the show vlan info:

Cat2950A#sho vlan

VLAN Name Status Ports

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

1 default active Fa0/1, Fa0/2, Fa0/3, Fa0/4

Fa0/5, Fa0/6, Fa0/7, Fa0/8

Fa0/9, Fa0/10, Fa0/11, Fa0/12

Fa0/13, Fa0/14, Fa0/15, Fa0/16

Fa0/17, Fa0/18, Fa0/19, Fa0/20

Fa0/21, Fa0/22, Fa0/23

1002 fddi-default act/unsup

1003 token-ring-default act/unsup

1004 fddinet-default act/unsup

1005 trnet-default act/unsup

VLAN Type SAID MTU Parent RingNo BridgeNo Stp BrdgMode Trans1 Trans2

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

1 enet 100001 1500 - - - - - 0 0

1002 fddi 101002 1500 - - - - - 0 0

1003 tr 101003 1500 - - - - srb 0 0

1004 fdnet 101004 1500 - - - ieee - 0 0

1005 trnet 101005 1500 - - - ibm - 0 0

Remote SPAN VLANs

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

Primary Secondary Type Ports

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

Cat2950A#

Cat2924A#sho vlan

VLAN Name Status Ports

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

1 default active Fa0/1, Fa0/2, Fa0/3, Fa0/4,

Fa0/5, Fa0/6, Fa0/7, Fa0/8,

Fa0/9, Fa0/10, Fa0/11, Fa0/12,

Fa0/13, Fa0/14, Fa0/15, Fa0/16,

Fa0/17, Fa0/18, Fa0/19, Fa0/20,

Fa0/21, Fa0/23, Fa0/24

1002 fddi-default active

1003 token-ring-default active

1004 fddinet-default active

1005 trnet-default active

VLAN Type SAID MTU Parent RingNo BridgeNo Stp BrdgMode Trans1 Trans2

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

1 enet 100001 1500 - - - - - 0 0

1002 fddi 101002 1500 - - - - - 0 0

1003 tr 101003 1500 - - - - srb 0 0

1004 fdnet 101004 1500 - - - ieee - 0 0

1005 trnet 101005 1500 - - - ibm - 0 0

rileymartin Tue, 09/11/2007 - 05:51

My previous post with the 'sho vlan' information was after I had added and then removed the additional VLANs. Here is the current vlan configuration showing the additional VLANs on the 2950 and that they are missing from one of the 2924s.

Cat2950A#sh vlan

VLAN Name Status Ports

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

1 default active Fa0/1, Fa0/2, Fa0/3, Fa0/4

Fa0/5, Fa0/6, Fa0/7, Fa0/8

Fa0/9, Fa0/10, Fa0/11, Fa0/12

Fa0/13, Fa0/14, Fa0/15, Fa0/16

Fa0/17, Fa0/18, Fa0/19, Fa0/20

Fa0/21, Fa0/22, Fa0/23

2 VLan2 active

3 VLan3 active

4 VLan4 active

5 VLan5 active

6 VLan6 active

7 VLan7 active

1002 fddi-default act/unsup

1003 token-ring-default act/unsup

1004 fddinet-default act/unsup

1005 trnet-default act/unsup

VLAN Type SAID MTU Parent RingNo BridgeNo Stp BrdgMode Trans1 Trans2

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

1 enet 100001 1500 - - - - - 0 0

2 enet 100002 1500 - - - - - 0 0

VLAN Type SAID MTU Parent RingNo BridgeNo Stp BrdgMode Trans1 Trans2

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

3 enet 100003 1500 - - - - - 0 0

4 enet 100004 1500 - - - - - 0 0

5 enet 100005 1500 - - - - - 0 0

6 enet 100006 1500 - - - - - 0 0

7 enet 100007 1500 - - - - - 0 0

1002 fddi 101002 1500 - - - - - 0 0

1003 tr 101003 1500 - - - - srb 0 0

1004 fdnet 101004 1500 - - - ieee - 0 0

1005 trnet 101005 1500 - - - ibm - 0 0

Remote SPAN VLANs

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

Primary Secondary Type Ports

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

Cat2924B#SH VLAN

VLAN Name Status Ports

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

1 default active Fa0/1, Fa0/2, Fa0/3, Fa0/4,

Fa0/5, Fa0/6, Fa0/7, Fa0/8,

Fa0/9, Fa0/10, Fa0/11, Fa0/12,

Fa0/13, Fa0/14, Fa0/15, Fa0/16,

Fa0/17, Fa0/18, Fa0/19, Fa0/20,

Fa0/21, Fa0/23, Fa0/24

1002 fddi-default active

1003 token-ring-default active

1004 fddinet-default active

1005 trnet-default active

VLAN Type SAID MTU Parent RingNo BridgeNo Stp BrdgMode Trans1 Trans2

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

1 enet 100001 1500 - - - - - 1002 1003

1002 fddi 101002 1500 - - - - - 1 1003

1003 tr 101003 1500 1005 - - - srb 1 1002

1004 fdnet 101004 1500 - - 1 ibm - 0 0

1005 trnet 101005 1500 - - 1 ibm - 0 0

Edison Ortiz Tue, 09/11/2007 - 06:39

Did you configure any vtp password ?

Let's see a 'show vtp password' output.

rileymartin Tue, 09/11/2007 - 06:18

Thanks for the link. I read through the various links however couldn't find anything that fixed the problem. I also couldn't find anything that said whether or not I have to change the VTP domain on a VTP client manually or if the domain name is configured when the client receives the VTP announcement. I also couldn't find how to reset the VTP domain name back to NULL or whatever the default is.

Jon Marshall Tue, 09/11/2007 - 06:44

Hi

The VTP domain is not sent through VTP advertisements so you need to configure it manually.

As per Sundar's post what are the configuration revision numbers on both switches ?

Jon

rileymartin Tue, 09/11/2007 - 07:03

Thanks to everyone for your help. I was missing a switchport mode trunk statement on one of the interfaces on the middle switch. That explains why I had connectivity but VTP wasn't working. Thanks again for everyone's help.

Kevin Dorrell Tue, 09/11/2007 - 07:52

Jon,

However, I have observed that if you take a brand new switch and add it to a network, it will learn and inherit the VTP domain name through VTP (but not the password). The VTP domain is included in the VTP message.

I have always thought there must be risks in that functionality, but there it is. Maybe it depends on the switch model and IOS revision.

The document that Mahmood posted is one of the best on cisco.com, and explains the subject really clearly. The flash animation in it is expecially cool.

Kevin Dorrell

Luxembourg

Actions

This Discussion