09-09-2012 10:16 AM - edited 03-07-2019 08:46 AM
Hi Everyone,
I was testing the VTP Pruning on cisco switches.
Switch A is VTP server mode and is connected to Switch B ---B is client.
Switch A is connected to Switch C. ---C is Client mode.
I configured layer 3 interface vlan 2 on Switch A.
All other switches show vlan 2 now .
No ports on all 3 switches are assigned to Vlan 2.
I enabled VTP pruning on server and now all client switches shows that VTP pruning is enabled.
Switch A
shows
A#sh int trunk
Port Mode Encapsulation Status Native vlan
Fa0/12 desirable n-802.1q trunking 1
Po10 on 802.1q trunking 1
Port Vlans allowed on trunk
Fa0/12 1-4094
Po10 1,10,20,30
Port Vlans allowed and active in management domain
Fa0/12 1-2,10,20,30
Po10 1,10,20,30
Port Vlans in spanning tree forwarding state and not pruned
Fa0/12 1,20
Po10 1,10,20,30
This is correct behaviour as vlan 2 is pruned now.
B shows
I
B#sh int trunk
Port Mode Encapsulation Status Native vlan
Po10 on 802.1q trunking 1
Port Vlans allowed on trunk
Po10 1,10,20,30
Port Vlans allowed and active in management domain
Po10 1,10,20,30
Port Vlans in spanning tree forwarding state and not pruned
Po10 1,10,20,30
This also seems ok
Switch C shows
sh int trunk
Port Mode Encapsulation Status Native vlan
Fa0/12 desirable 802.1q trunking 1
Port Vlans allowed on trunk
Fa0/12 1-4094
Port Vlans allowed and active in management domain
Fa0/12 1-2,10,20,30
Port Vlans in spanning tree forwarding state and not pruned
Fa0/12 1-2,10,20,30
My question is why switch C shows vlan 2 as not pruned.
Switch c has only switch A as its nei.
Thanks
Solved! Go to Solution.
09-09-2012 01:27 PM
Yes, if switch A is the VTP server, than you need to configure it there, so switch A can replicate it to switch B and C.
Also, for testing and learning, this is fine. If this is for production and you only have 3 switches with handful vlans, VTP doesn't do much for you. Some times VTP causes more issues than helping you.
HTH
Reza
09-09-2012 10:40 AM
Hi Mahesh,
Switch-B does not show vlan 2 at all.
Can you post your configs?
HTH
Reza
09-09-2012 12:08 PM
Hi Reza,
Thanks for reply.
I have attached run config of all 3 switches under first post.
Mahesh
09-09-2012 12:26 PM
Hi Mahesh,
Sorry, I didn't see the attachments. Looking at switch-A config, I don't see any vtp config like vtp name, vtp mode, etc...
can you clarify?
Thanks,
Reza
09-09-2012 12:50 PM
Hi Reza,
Here is info from 3 switches
Switch B
B#sh vtp sta
3550SMIB#sh vtp status
VTP Version : running VTP2
Configuration Revision : 48
Maximum VLANs supported locally : 1005
Number of existing VLANs : 9
VTP Operating Mode : Client
VTP Domain Name : manveer.com
VTP Pruning Mode : Enabled
VTP V2 Mode : Enabled
VTP Traps Generation : Disabled
MD5 digest : 0x8E 0xB5 0x29 0x8B 0x11 0x17 0xC3 0x11
Configuration last modified by 2.0.0.1 at 9-9-12 16:49:09
B#sh int trunk
Port Mode Encapsulation Status Native vlan
Po10 on 802.1q trunking 1
Port Vlans allowed on trunk
Po10 1,10,20,30
Port Vlans allowed and active in management domain
Po10 1,10,20,30
Port Vlans in spanning tree forwarding state and not pruned
Po10 1,10,20,30
A#sh vtp status
VTP Version : running VTP2
Configuration Revision : 48
Maximum VLANs supported locally : 1005
Number of existing VLANs : 9
VTP Operating Mode : Server
VTP Domain Name : manveer.com
VTP Pruning Mode : Enabled
VTP V2 Mode : Enabled
VTP Traps Generation : Disabled
MD5 digest : 0x8E 0xB5 0x29 0x8B 0x11 0x17 0xC3 0x11
Configuration last modified by 2.0.0.1 at 9-9-12 16:49:09
Local updater ID is 2.0.0.1 on interface Vl2 (lowest numbered VLAN interface fou
nd)
A#sh int trunk
Port Mode Encapsulation Status Native vlan
Fa0/12 desirable n-802.1q trunking 1
Po10 on 802.1q trunking 1
Port Vlans allowed on trunk
Fa0/12 1-4094
Po10 1,10,20,30
Port Vlans allowed and active in management domain
Fa0/12 1-2,10,20,30
Po10 1,10,20,30
Port Vlans in spanning tree forwarding state and not pruned
Fa0/12 1,20
Po10 1,10,20,30
C#sh vtp status
VTP Version : 2
Configuration Revision : 48
Maximum VLANs supported locally : 250
Number of existing VLANs : 9
VTP Operating Mode : Client
VTP Domain Name : manveer.com
VTP Pruning Mode : Enabled
VTP V2 Mode : Enabled
VTP Traps Generation : Disabled
MD5 digest : 0x8E 0xB5 0x29 0x8B 0x11 0x17 0xC3 0x11
Configuration last modified by 2.0.0.1 at 9-9-12 16:49:09
C# sh int trunk
Port Mode Encapsulation Status Native vlan
Fa0/12 desirable 802.1q trunking 1
Port Vlans allowed on trunk
Fa0/12 1-4094
Port Vlans allowed and active in management domain
Fa0/12 1-2,10,20,30
Port Vlans in spanning tree forwarding state and not pruned
Fa0/12 1-2,10,20,30
HEre is config u requested.Also under original posts at the bottom there is 3 attachments with all sh run config.
Thanks
MAhesh
09-09-2012 01:05 PM
Hi Mahesh,
Switch-A is the vtp server, but I don't see vlan 2 under portchannel 10. Can you add it and try again?
interface Port-channel10
switchport trunk encapsulation dot1q
--More-- switchport trunk allowed vlan 1,10,20,30
switchport mode trunk
speed nonegotiate
HTH
Reza
09-09-2012 01:15 PM
Hi Reza,
Thanks for reply.
Should i config that on switch A only?
MAhesh
09-09-2012 01:27 PM
Yes, if switch A is the VTP server, than you need to configure it there, so switch A can replicate it to switch B and C.
Also, for testing and learning, this is fine. If this is for production and you only have 3 switches with handful vlans, VTP doesn't do much for you. Some times VTP causes more issues than helping you.
HTH
Reza
09-09-2012 06:12 PM
Hi Reza,
Thanks for all the replies.
I was doing this for learning purposes.
regards
Mahesh
09-09-2012 01:26 PM
Hi Reza,
I did as you said on last post on Switch A and B.
Switch C still shows
C#sh int trunk
Port Mode Encapsulation Status Native vlan
Fa0/12 desirable 802.1q trunking 1
Port Vlans allowed on trunk
Fa0/12 1-4094
Port Vlans allowed and active in management domain
Fa0/12 1-2,10,20,30
Port Vlans in spanning tree forwarding state and not pruned
Fa0/12 1-2,10,20,30
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