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VTP update over L2TPV3 fails

tgusset
Level 1
Level 1

Hello

we are expanding a trunk port over a L2TPV3 tunnel (in port mode):

trunk port <-> 2811 <-tunnel-> 2811 <--> trunk port

Everything works fine but VTP updates are failing.

Sniffer shows that VTP packets are out of order after the tunnel. There a 3 packets and order after the tunnel is 1,3,2. So packet #2 is as big as MTU and will be transfered fragmented over the tunnel. It looks like the router on the far end of the tunnel delivers reassembled packets later.

We can't increase MTU in the tunnel network. Decreasing MTU in the LAN is also no option.

Q's:

Is there a way to limit VTP packet size on the VTP server switch?

Is there a way to force tunnel routers to deliver fragmented and reassembled packets in original order?

Thanks in advance

Thomas

1 Reply 1

Giuseppe Larosa
Hall of Fame
Hall of Fame

Hello Thomas,

>> Is there a way to force tunnel routers to deliver fragmented and reassembled packets in original order?

see

Sequencing section

http://www.cisco.com/en/US/docs/ios/12_3t/12_3t2/feature/guide/gtl2tpv3.html#wp1042754

Hope to help

Giuseppe

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