Hi i've a ticket with Draytek Support which has been open since the 13th September, for a nice new shiney 3900 to replace one of our 3300's that has been locking up occasionally.
the 3900 seems to cope well with the incoming single VPN lan-to-lan links, from 4 other vigors, but fails terribly with the vpn trunk from the 3300 at one site.
The original firmware gave no data traffic over certain combinations/moon phases/order of disconnection, day of the week etc .
We've had new firmwares and are now up to 1442 release, and still no fix, and we've checked bootloaders etc and all seem ok to the support people, we thought that they had found the issue blaming connection names that were too long! so now everything is clearly labeled as m1,m2 :shock:
But once connected over a period of minutes to hours the performance drops off very badly, with pings going from (single vpn ping was 45ms) ocacional 100ms upto 350-450ms!

My query is 'is anyone using a 3900 to recieve trunked connections from ANY other router? - especially a 3300?
if it does work, any chance of some gems of wisdom, maybe what ip ranges on each side of the network?

The vpn trunk works perfectly when swapped the 3900 for the original 3300, I believe this applies the 2960 series too.. anyone got this working?

I'm using a 3900 to a 3300, with VPN trunking. We don't have a problem with performance dropping off, but we do have a problem that if any 1 of the VPN trunks goes down then the connection becomes unreliable. It seems that the "Trunk" still tries to send data over the dropped tunnel and so packet loss becomes quite high until we manually disable the failed tunnel and remove it from the trunk configuration at both ends.

We've got 3 ADSL lines at each location with Draytek 120 modems feeding the 3300 and 3900.

Have you set separate GRE IP ranges on each tunnel? That was essential for us in getting it to work at all.

Hi, does sound familiar, althought the 1.0.6 release firmware semms a lot more stable. can I ask if you have any other vpns in or out of either end? - as we are now looking at this a possible cause of the issue.

Thanks for taking the time to reply!

Hi,
Yes both sites have a single (non trunked) VPN to a 3rd site. This is a different IP range and connects to a Draytek 2820.