trunking protocol

[kapupu]

My question is how come the trunk is not establish?


SwitchA config

interface FastEthernet0/1
switchport trunk encapsulation dot1q
switchport mode trunk

A#sh vtp status
VTP Version : 2
Configuration Revision : 1
Maximum VLANs supported locally : 68
Number of existing VLANs : 6
VTP Operating Mode : Server

A#sh inte fa0/1 sw
A#sh inte fa0/1 switchport
Name: Fa0/1
Switchport: Enabled
Administrative mode: trunk
Operational Mode: trunk
Administrative Trunking Encapsulation: dot1q
Operational Trunking Encapsulation: dot1q
Negotiation of Trunking: Disabled
Access Mode VLAN: 0 ((Inactive))
Trunking Native Mode VLAN: 1 (default)
Trunking VLANs Enabled: ALL
Trunking VLANs Active: 1,20
Pruning VLANs Enabled: 2-1001





SwitchB config

interface FastEthernet0/1
switchport trunk encapsulation dot1q
switchport mode trunk

B#sh vtp sta
B#sh vtp status
VTP Version : 2
Configuration Revision : 0
Maximum VLANs supported locally : 68
Number of existing VLANs : 5
VTP Operating Mode : Client


B#sh inter fa0/1 switchport
Name: Fa0/1
Switchport: Enabled
Administrative mode: trunk
Operational Mode: trunk
Administrative Trunking Encapsulation: dot1q
Operational Trunking Encapsulation: dot1q
Negotiation of Trunking: Disabled
Access Mode VLAN: 0 ((Inactive))
Trunking Native Mode VLAN: 1 (default)
Trunking VLANs Enabled: ALL
Trunking VLANs Active: 1
Pruning VLANs Enabled: 2-1001




B#sh vlan brief
VLAN Name Status Ports
---- -------------------------------- --------- -------------------------------
1 default active Fa0/2, Fa0/3, Fa0/4, Fa0/5,
Fa0/6, Fa0/7, Fa0/8, Fa0/9,
Fa0/10, Fa0/11, Fa0/12
1002 fddi-default active
1003 token-ring-default active
1004 fddinet-default active
1005 trnet-default

 

[vipergg]

Check that vtp domain names match on each side . What does it show when you do a show int trunk ? Do you have layer 1 between the switches ?

 

[imbadatthis]

do you have an Active port that is part of another vlan in switch B? otherwise VTP is doing its job ....
try adding a port in switch B to vlan 20


We must go always forward, not backward
always up, not down and always twirling twirling towards infinity.

 

[vipergg]

Because switch B is a client he would have to change the role to server or transparent to add a vlan . Also try bouncing the connecting ports..

 

[kapupu]

I configure the vtp domain and password and it works.

 

[dgrizzard]

Not sure if you got your "issue" resolved. Just wanted to clear up a few things, VTP is not (despite the name) a trunking protocol, it is for exchaing VLAN information inside your network between switches. I would also look up the pitfalls and security concerns before implementing it.

Also, actual 802.1q trunking is working by your show vlan command from switch_b.

B#sh vlan brief
VLAN Name                             Status    Ports
---- -------------------------------- --------- -------------------------------
1    default                          active    Fa0/2, Fa0/3, Fa0/4, Fa0/5,
                                                Fa0/6, Fa0/7, Fa0/8, Fa0/9,
                                                Fa0/10, Fa0/11, Fa0/12
1002 fddi-default                     active
1003 token-ring-default               active
1004 fddinet-default                  active
1005 trnet-default

Since Fa0/1 is not listed, that means it is considered a trunk port.