Cisco vtp not updating
Everything was working fine in terms of VLAN updates through out the topology.
I am getting following issue after configuring SW1 as a TRANSPARENT MODE and SW3 & SW4 as a CLIENT MODE.- SW3 does not update or delete VLAN definition.-SW4 does update and delete vlan definition.-SW2 is configured as a SERVER mode.
These advertisements inform nearby Catalyst switches with a variety of information, including the VTP Domain name, configuration revision number, timestamp, MD5 encryption hash code, and the number of subset advertisements to follow.
The configuration version number is a value each switch stores to help it identify new changes made in the VTP domain.
SW2:(Server)Port Vlans in spanning tree forwarding state and not pruned Fa0/6 67,146Fa0/13 5,7,22,43,58,67,79,146Fa0/14 none Fa0/15 none SW1(Transparent)In the INE topology, SW1 is connected to SW3 using ports fa0/16 - 18. Port Vlans in spanning tree forwarding state and not pruned Fa0/13 1,5,7,22,43,58,67,79,123,146,456Fa0/14 1,5,7,22,43,58,67,79,123,146,456Fa0/15 1,5,7,22,43,58,67,79,123,146,456Fa0/16 5,7,22,43,58,67,79,123,146,456Fa0/17 5,7,22,43,58,67,79,146Fa0/18 5,7,22,43,58,67,79,146Fa0/19 1,5,7,22,43,58,67,79,123,146,456Fa0/20 123,456Fa0/21 123,456I believe that once you correct that issue, you'll see the VTP advertisements start to work as expected.
Your trunk ports on the transparent switch needs to have all of it's interfaces forwarding for VLAN 1, or at least to the ones that need to send the VTP advertisement..
I have tried following things- rebooting SW3 did not fix this problem- updated VTP domain,password,modes to trigger updates but no change.- SW3 starts updating vlan database once I configure SW1 as a server mode.- but SW3 does not update vlan definition if I configure SW1 as a TRANSPARENT MODE.
Answer: I believe this is not working because SW1 and SW2 are not forwaring VLAN 1 over some of their trunk links. According to the INE topology, SW1 and SW2 are connected to each other using ports fa0/13 - 15.According to SWITCH book by Sivasubramanian, Froom, Frahim (2010 p.56): With Cisco IOS Release 12.1(11b)E or later, you can remove VLAN 1 from a trunk port.Even after removing VLAN 1 from a trunk, the trunk interface continues to send and receive management traffic.Depending on how many VLANs are configured in the domain, there might be more than one Subset Advertisement sent to ensure all VLAN information is updated on the VTP Clients. The Code field for a Subset Advertisement of this type is set to 0x02 while the Sequence No.Comparing the fields of this message with the previous one, you'll notice most of them are identical, except for the Sequence No. field contains the sequence of the packet in the stream of packets following a summary advertisement.Lastly, summary advertisements are usually followed by Subset Advertisements, this is indicated by the Followers field and is the next message we'll be closely examining.As mentioned in the previous message, when VLAN changes are made on the Catalyst VTP Server, it will then issue a Summary Advertisement, followed by a Subset Advertisement.When a switch receives a summary advertisement message, it will first compare the VTP domain name (Mgmt Domain Name field) with its own.If the Domain Name is found to be different, it will discard the message and forward it out its trunk links.I think we learned that there are some errors in documentation.Documentation states that VTP version 1 will forward advertisements through a VTP transparent switch if the domain matches.