L2TPV3 + switches

[Gaj Anna]

Hi All,

I experienced a issue when tesing an l2tpv3 tunnel between two sites across WAN. The requirement is to extend the LAN from site A to Site B. During tesing the l2tpv3 (ethernet to ethernet) when two PC's are connetced at the ethernet ports of the tunnel interfaces across each site they are reachable. When these interfaces are conencted to switches (to a access port vlan) on each side the network of site A goes down. Could not able to see any debugs at all in the switches. Packet capture on site B at the switch access port showed that the ARP requestes were received correctly from site B's router for the Site A's LAN addresses. Site A switch is a VTP server and Site B is transparent. The MTU size used is 1500 bytes.

Anyone have come across this issue and please advice if I have missed anything?

Thanks in advice.

Ted

[Ivan Krimmel]

Hi Ted,

were you able to capture any errors in the logs on Site A when it went down?

[Gaj Anna]

Hi Ivan,

No not at all. That was bit weired and cannot see any logs. Only I could see the ARP table some times receives different for same IP's even after diasbling proxy-arp at ethernet of Site A router interface.

Ted

[Ivan Krimmel]

Hi Ted,

please do share the logs you have, as well as the configuration snippets taken off the PE boxes, I mean the L2TPv3 termination endpoints. Also did you notice anything on the switched which were being connected? like STP issues etc. What was the SRP state during the test/meltdown?

HTH,

Ivan.

[Gaj Anna]

Hi Ivan,

UNfortunately I dont have any logs because I couldnt see anything. There was no STP issues as well. I will do the test again and if I could see any logs I will post here.

Ted

[Ivan Krimmel]

Hey Ted,

better go for a TAC SR to have somebody with you during the test.

Cheers,

Ivan.