On 6/25/2013 7:04 AM, Linda Dunbar wrote:
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.
Do these apps set DF=1? If so, they ought to be prepared to handle ICMP PTB messages. If not, they shouldn't be setting PTB.
However, my view remains that PTB is for when a link cannot handle a packet - not when it chooses not to do so electively. The only packet that ought to be too big for GRE is one that exceeds the max payload of IP after encapsulation. Others ought to be fragmented at the GRE ingress and reassembled at the GRE egress at the outer IP layer, exactly because IP *can* do this.
Joe _______________________________________________ Int-area mailing list [email protected] https://www.ietf.org/mailman/listinfo/int-area
