> No, it isn't, but as far as I can see, any tunnel spec needs to state how > this applies. If the tunnel keeps no packet state, how is it going to perform > PMTUD? If the answer is that the tunnel end points need to be configured in > some way, that needs to be stated too. > > Sorry to go on, but when I review a draft, I like to feel that if I had to, I > could code it, and in this case I just don't know how I would code the AFBR > with respect to PMTUD and/or including a fragment header.
Typically tunnels are either configured with a fixed MTU, or do path MTU discovery like any other host on the Internet. E.g. for a point to point tunnel it can dynamically set the MTU on a tunnel interface based on received PMTUD messages (or PLMTUD probing). For point to multi-point tunnels it maintains a PMTUD cache. There’s no magic for tunnels here, just like Joe says. Cheers, Ole _______________________________________________ Softwires mailing list [email protected] https://www.ietf.org/mailman/listinfo/softwires
