Joe, On Jun 25, 2013, at 12:50 PM, "Joe Touch" <[email protected]> wrote:
> > > 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. If a physical link has an MTU of 1500, can you configure it and set it to be 1300, despite the hardware being able to do 1500? Are you suggesting that a GRE tunnel has a Tunnel MTU of 65535 - encap always? > > Joe Thumb typed by Carlos Pignataro. Excuze typofraphicak errows _______________________________________________ Int-area mailing list [email protected] https://www.ietf.org/mailman/listinfo/int-area
