CCIE Pursuit Blog

September 25, 2007

VTP: More On The Local updater ID

This post is a follow up to VTP: Which VTP Server Generated The Most Recent Update?  I didn’t want to make that post any longer than it already was.  Here’s some more information about the “Local update ID” in VTP.

If you have multiple IP addresses on your VTP server, the Local updater will use the first IP address found:

sw1(config-if)#do sh ip int br | e ass
Interface              IP-Address      OK? Method Status                Protocol
Loopback0              10.0.0.1        YES manual up                    up
Loopback1              100.100.100.100 YES manual up                    up
Loopback2              220.0.0.100     YES manual up                    up

sw1(config-if)#do sh vtp statu | i Local updater
Local updater ID is 10.0.0.1 on interface Lo0 (first layer3 interface found)

Just for fun, let’s get rid of lo0 and see what IP address it will choose (either lo1 or lo2):

sw1(config-if)#no int lo0
01:47:42: %LINK-5-CHANGED: Interface Loopback0, changed state to administratively down
01:47:43: %LINEPROTO-5-UPDOWN: Line protocol on Interface Loopback0, changed state to down
sw1(config)#do sh vtp statu | i Local
Local updater ID is 100.100.100.100 on interface Lo1 (first layer3 interface found)

The Local updater ID will choose the lowest VLAN interface IP address over all IP addresses others:

sw1(config-if)#do sh ip int br | e ass
Interface              IP-Address      OK? Method Status                Protocol
Vlan6                       6.0.0.1         YES manual up                    up
Vlan69                     69.0.0.1        YES manual up                    up
Loopback0              10.0.0.1        YES manual up                    up
Loopback1              100.100.100.100 YES manual up                    up
Loopback2              220.0.0.100     YES manual up                    up

sw1(config-if)#do sh vtp statu | i Local
Local updater ID is 6.0.0.1 on interface Vl6 (lowest numbered VLAN interface found)

If you have multiple IP addresses, you can manually set the Local updater ID:

sw1(config)#do sh ip int br | e ass
Interface              IP-Address      OK? Method Status                Protocol
Vlan6                       6.0.0.1           YES manual up                    up
Vlan69                     69.0.0.1        YES manual up                    up
Loopback0              10.0.0.1        YES manual up                    up
Loopback1              100.100.100.100 YES manual up                    up
Loopback2              220.0.0.100     YES manual up                    up

sw1(config)#vtp ?

  interface  Configure interface as the preferred source for the VTP IP updater address.

sw1(config)#vtp interface ?
  WORD  The name of the interface providing the VTP updater ID for this device. <-word??  really?

sw1(config)#vtp interface lo1 ?
  only  Use only this interface’s IP address as the VTP IP updater address.
  <cr>

sw1(config)#vtp interface lo1
sw1(config)#do sh vtp stat | b Local
Local updater ID is 100.100.100.100 on interface Lo1 (preferred interface)
Preferred interface name is lo1

With “only” keyword:

sw1(config)#vtp interface lo2 only
sw1(config)#do sh vtp stat | b Local
Local updater ID is 220.0.0.100 on interface Lo2 (preferred interface)
Preferred interface name is lo2 (mandatory)

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3 Comments »

  1. […] VTP: More On The Local updater ID […]

    Pingback by VTP: Local updater ID on VTP Transparent Switches « CCIE Pursuit — September 25, 2007 @ 6:28 pm | Reply

  2. Doh, Just read your follow up on VTP Local update an see that you already came across it. Good man, keep up the good work.

    SteveP

    Comment by SteveP — September 27, 2007 @ 5:17 am | Reply

  3. […] Если вам интересны подробности их можно посмотреть у CCIE Pursuit. […]

    Pingback by Errata: CCIE R&S Exam Cert Guide part3 | I Love Networking — May 25, 2008 @ 8:56 am | Reply


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