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trunk not working

Hi,

I have an a simple configuration between two switches.

An 2950 with IOS 12.1(20)EA1a connected in trunk to an 2960 with IOS 12.2(25r)SEE1.

I have configured the same vtp domain name, I see from command "sh int status"

that both port link are in trunk but the vlans don't pass from a switch to the other excluded native vlan (1).

What can be ?

best regards

Lorenzo

2 ACCEPTED SOLUTIONS

Accepted Solutions
Cisco Employee

Re: trunk not working

Lorenzo,

Its good to know that the problem is resolved. I am gald to help you. Please continue your participation in the netpro forum.

** Note, Please use the rating system to rate all the helpful posts and appreciate our efforts that we all our putting in our busy schedules.

-amit singh

Cisco Employee

Re: trunk not working

Thanks Jon for appreciating the post. Yeah agree with you.. we get a lot to learn daily..

Lets keep up our spirits high...

-amit singh

12 REPLIES
Hall of Fame Super Blue

Re: trunk not working

Hi Lorenzo

Is one of the switches a VTP server and one a vtp client. Are you saying that if you add a vlan to one of your switches it doesn't get propogated to the other.

Not clear what you mean about the native vlan.

Could you post output of sh vtp status and elaborate on your problem.

Jon

New Member

Re: trunk not working

Hi Jon,

are both VTP server however I attach

both VTP status:

for 2950:

sw2-Bolo#sh vtp status

VTP Version : 2

Configuration Revision : 204

Maximum VLANs supported locally : 250

Number of existing VLANs : 7

VTP Operating Mode : Server

VTP Domain Name : racka

VTP Pruning Mode : Enabled

VTP V2 Mode : Disabled

VTP Traps Generation : Disabled

MD5 digest : 0x71 0x16 0xA6 0xE7 0x70 0xC9 0xBB 0xB1

Configuration last modified by 192.168.10.201 at 9-11-95 22:10:58

Local updater ID is 192.168.10.202 on interface Vl1 (lowest numbered VLAN interf

ace found)

for 2960:

sw7-bolo#sh vtp sta

VTP Version : 2

Configuration Revision : 7

Maximum VLANs supported locally : 255

Number of existing VLANs : 5

VTP Operating Mode : Server

VTP Domain Name : racka

VTP Pruning Mode : Enabled

VTP V2 Mode : Disabled

VTP Traps Generation : Disabled

MD5 digest : 0xBC 0x08 0x63 0xCF 0x44 0x58 0x11 0x32

Configuration last modified by 192.168.10.207 at 3-14-93 04:34:44

Local updater ID is 192.168.10.207 on interface Vl1 (lowest numbered VLAN interf

ace found)

Cisco Employee

Re: trunk not working

Please paste show VTP counters from both the switches.

New Member

Re: trunk not working

Hi asingh 2

here is:

from 2950 :

sw2-Bolo#sh vtp counters

VTP statistics:

Summary advertisements received : 263629

Subset advertisements received : 126

Request advertisements received : 617

Summary advertisements transmitted : 267977

Subset advertisements transmitted : 719

Request advertisements transmitted : 0

Number of config revision errors : 0

Number of config digest errors : 0

Number of V1 summary errors : 0

from 2960 :

sw7-bolo#sh vtp counters

VTP statistics:

Summary advertisements received : 4686

Subset advertisements received : 2361

Request advertisements received : 0

Summary advertisements transmitted : 899

Subset advertisements transmitted : 8

Request advertisements transmitted : 2326

Number of config revision errors : 0

Number of config digest errors : 2361

Number of V1 summary errors : 0

New Member

Re: trunk not working

Hi Lorenzo,

Is the trunking set to the same (.1q or isl) on both switches?

Also it would help if you could attatch the configs?

Urfan

New Member

Re: trunk not working

Hi,

yes are both configured on 802.1q

I attach config for both port:

2950:

sw2-Bolo#sh int fa 0/23 switchport

Name: Fa0/23

Switchport: Enabled

Administrative Mode: trunk

Operational Mode: trunk

Administrative Trunking Encapsulation: dot1q

Operational Trunking Encapsulation: dot1q

Negotiation of Trunking: On

Access Mode VLAN: 1 (default)

Trunking Native Mode VLAN: 1 (default)

Voice VLAN: none

Administrative private-vlan host-association: none

Administrative private-vlan mapping: none

Administrative private-vlan trunk native VLAN: none

Administrative private-vlan trunk encapsulation: dot1q

Administrative private-vlan trunk normal VLANs: none

Administrative private-vlan trunk private VLANs: none

Operational private-vlan: none

Trunking VLANs Enabled: ALL

Pruning VLANs Enabled: 2-1001

Capture Mode Disabled

Capture VLANs Allowed: ALL

Protected: false

2960:

sw7-bolo#sh int fa 0/23 sw

Name: Fa0/23

Switchport: Enabled

Administrative Mode: dynamic auto

Operational Mode: trunk

Administrative Trunking Encapsulation: dot1q

Operational Trunking Encapsulation: dot1q

Negotiation of Trunking: On

Access Mode VLAN: 1 (default)

Trunking Native Mode VLAN: 1 (default)

Administrative Native VLAN tagging: enabled

Voice VLAN: none

Administrative private-vlan host-association: none

Administrative private-vlan mapping: none

Administrative private-vlan trunk native VLAN: none

Administrative private-vlan trunk Native VLAN tagging: enabled

Administrative private-vlan trunk encapsulation: dot1q

Administrative private-vlan trunk normal VLANs: none

Administrative private-vlan trunk private VLANs: none

Operational private-vlan: none

Trunking VLANs Enabled: ALL

Pruning VLANs Enabled: 2-1001

Capture Mode Disabled

Capture VLANs Allowed: ALL

Cisco Employee

Re: trunk not working

Hi,

You have a VTP password mismatch on 2960 switch.

Check this:

from 2960 :

sw7-bolo#sh vtp counters

VTP statistics:

Summary advertisements received : 4686

Subset advertisements received : 2361

Request advertisements received : 0

Summary advertisements transmitted : 899

Subset advertisements transmitted : 8

Request advertisements transmitted : 2326

Number of config revision errors : 0

Number of config digest errors : 2361 ---> See here

Number of V1 summary errors : 0

Please make sure that you have the same VTP password at both the ends. Change the password and you should be good to go.

HTH,Please rate all the posts that have helped.

-amit singh

New Member

Re: trunk not working

Hi amit,

I had differently password.

Now I have seen insert the same password

for both and all working fine.

Best regards

Lorenzo

Cisco Employee

Re: trunk not working

Lorenzo,

Its good to know that the problem is resolved. I am gald to help you. Please continue your participation in the netpro forum.

** Note, Please use the rating system to rate all the helpful posts and appreciate our efforts that we all our putting in our busy schedules.

-amit singh

Hall of Fame Super Blue

Re: trunk not working

Hi Amit

That's the beauty of doing NetPro :). Never knew this was how to tell a password mismatch.

Deserves 5 points.

Jon

Cisco Employee

Re: trunk not working

Thanks Jon for appreciating the post. Yeah agree with you.. we get a lot to learn daily..

Lets keep up our spirits high...

-amit singh

New Member

Re: trunk not working

hi Lorenzo,

I want to ask you something about 802.1q trunk on cat2960.

It seems me that cat2960 TAGs the NATIVE VLAN (default 1) in trunk links ("Administrative Native VLAN tagging: enabled").

Standard 802.1q does not want native vlan tagging !!!

Switch#sh interfaces f0/1 switchport

Name: Fa0/1

Switchport: Enabled

Administrative Mode: trunk

Operational Mode: trunk

Administrative Trunking Encapsulation: dot1q

Operational Trunking Encapsulation: dot1q

Negotiation of Trunking: On

Access Mode VLAN: 1 (default)

Trunking Native Mode VLAN: 1 (default)

Administrative Native VLAN tagging: enabled

Voice VLAN: none

Administrative private-vlan host-association: none

Administrative private-vlan mapping: none

Administrative private-vlan trunk native VLAN: none

Administrative private-vlan trunk Native VLAN tagging: enabled

Administrative private-vlan trunk encapsulation: dot1q

Administrative private-vlan trunk normal VLANs: none

Administrative private-vlan trunk private VLANs: none

Operational private-vlan: none

Trunking VLANs Enabled: ALL

Pruning VLANs Enabled: 2-1001

Capture Mode Disabled

Capture VLANs Allowed: ALL

Protected: false

Unknown unicast blocked: disabled

Unknown multicast blocked: disabled

Appliance trust: none

Switch#

This vlan1 tag in 802.1q trunk is a problem when I try using a cisco2610 to do INTERVLAN routing.

The cisco2610 does not tag native vlan, so there is a mismath !

Do you know if is there a way to UNTAG the NATIVE VLAN on cat2960 ?

thanks

francesco

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