The last couple of weeks I have been designing and working on a rather large switched project. Overall the topology isn’t complex, it just spans a large area. The length is about 3 kilometres.

The project uses 2960S/G and 3560x model switches with SFP SM Fibre between each with redundancy in between each switch. Once spanning tree was sorted with setting priorities as required by the brief I started to implement VTP.

Working over two days I was copying the config of VTP across from a base config. I have found a few little caveats.

  • VTP configs aren’t displayed in Show Run. When you are making a base template for a common group of switches you must ensure you either input the information or manually add it to each switch.
  • VTP Password. Make sure you have the same password across the entire domain! Enough said.
I found in hindsight it is best to configure VTP if you decide on using it before you create VLANs. Designate what switches you want to be the servers and where you want client and transparent switches. This way you won’t have to deal with any issues pertaining to revision numbers or human input!
I did lose my VLAN database once due to not paying attention and placing the wrong switch as a server. Shoop! There goes some VLANs!
No wonder there are though out there who love/hate it. It’s that kind of protocol!
And as always, wr mem.

2 thoughts on “VTP – Very Trying Protocol (Vlan Trunking Protocol)

  1. One thing that I do to cover myself in terms of the vlan database is to backup vlan.dat to a tftp or scp server every so often. On my core I have an EEM Script setup to do this automatically.

    event manager applet backup-vlan
    event timer cron cron-entry “0 23 * * *” maxrun 60000
    action 1 cli command “enable”
    action 2 cli command “configure terminal”
    action 3 cli command “file prompt quiet”
    action 4 cli command “end”
    action 5 cli command “copy const_nvram:/vlan.dat scp://scpbackup:[email protected]/vlan.dat”
    action 6 cli command “configure terminal”
    action 7 cli command “no file prompt quiet”
    action 8 cli command “end”

    1. Wow. Thank you. That would be handy indeed. I know I was doing show run | s vtp but that makes it easier. Much easier! Just was a headache after so many switches that it wiped. Lack of sleep most likely đŸ˜€

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