[c-nsp] GRE packets drop

[Alex Wa]

Hi,
   
  We're having a weird problem in one of our remote offices, connected through a GRE tunnel (using internet). The remote ISP, aparently is dropping randomly (or selectively) some 
GRE packets. when we ping the remote physical interface through the tunnel some packet drops are observed, but if icmp packets don't get into the tunnel they are never dropped. this is causing the ospf adjacencies to go down for no reason and is giving us a hard time. We've changed the tunel interface MTU to 1400, but it didn't work. besides OSPF's hello are less than a hundred octets, and i don't see a reason for the ISP dropping so small packets. The interface connected to the provider is a Gigabit Ethernet. Any suggestion to avoid this behaviour? any hint?
   
  Alejandro Wainshtok
  Network Engineer
  CCNP