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Re: [Gen-art] Review of draft-ietf-6man-rfc1981bis-04

2017-02-14 12:55:21

On Feb 14, 2017, at 10:33 AM, otroan(_at_)employees(_dot_)org wrote:

*If*  you care about packet loss, then your only option is to probe the path 
with with
synthetic data that exactly mimics the live data, or not to probe at all and 
live
with the 1280. As I said 1280 is pretty close to 1496 which is all most 
networks
will give you in practice.

Yes, but sending at 1280 does not work for IP tunnels. The whole purpose of 
the minimum MTU was to give space for tunnel headers (1500-1280).

I'm confused by that statement. https://tools.ietf.org/html/rfc7676#section-3.2 
indicates that a GRE tunnel on IPv6 and carrying an IPv6 payload works with a 
PMTU of 1280, and AFAIK it is among the larger tunnel headers. What tunnels 
does a PMTU of 1280 not work for?