Ron, Those applications ignore the ICMP messages and keep sending data frames as if there is no ICMP message received. We ran into this problem in testing Video distribution system. After the first few frames, the receivers can't receive anything. After lengthy debugging, we found out that an intermediate node drops packets when GRE encapsulated frames exceed the link MTU. We tested that ICMP message is sent back, but the source node didn't respond. We tried several setting as Joe pointed out. Some guest OSs change behavior, some don't.
Linda > -----Original Message----- > From: Ronald Bonica [mailto:[email protected]] > Sent: Wednesday, June 26, 2013 8:00 AM > To: Linda Dunbar; Joe Touch; Carlos Pignataro (cpignata) > Cc: Internet Area > Subject: RE: [Int-area] New Version Notification for draft-bonica- > intarea-gre-mtu-00.txt > > Linda, > > What do these platforms do when they receive an ICMP Packet too big > from a router that isn't a tunnel ingress? > > Ron > > > > -----Original Message----- > > From: Linda Dunbar [mailto:[email protected]] > > Sent: Tuesday, June 25, 2013 10:05 AM > > To: Joe Touch; Carlos Pignataro (cpignata) > > Cc: Ronald Bonica; Internet Area > > Subject: RE: [Int-area] New Version Notification for draft-bonica- > > intarea-gre-mtu-00.txt > > > > Ron, > > > > Your draft recommends that the ingress node discards the frame and > > sends ICMP msg to the source node when the size of GRE encapsulated > > frame exceeds link MTU. > > We experienced that Window XP doesn't adjust frame size after > receiving > > ICMP message. Many Linux based applications don't do anything either > > with the MTU ICMP message. I think your draft should point those > issues > > out and recommend fragmentation approach under those circumstances. > > > > Linda > > > > > > > > _______________________________________________ Int-area mailing list [email protected] https://www.ietf.org/mailman/listinfo/int-area
