Re: [Gen-art] Review of draft-ietf-6man-rfc1981bis-04 Tue, 14 February 2017 18:33 UTC

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Subject: Re: [Gen-art] Review of draft-ietf-6man-rfc1981bis-04
Date: Tue, 14 Feb 2017 19:33:09 +0100
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To: Stewart Bryant <>
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> *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).

> When I think about the people asking for fast re-route to minimise packet loss, it seems
> very strange to deliberately induce loss to try to stretch the MTU by 15%.

Please show the data that there is significant loss. The measurements I have found has not shown that.
If not, then let's please leave that argument on the shelf.

(And please don't read me wrong, I think we should get DNS fixed, that we should fix the IP tunnelling protocols, and that we should get IP fragmentation deprecated).

But right here, right now. PMTUD is for many problems the only solution on the table.
We as a community can choose not to elevate the standard of course, and that will of course not have any big consequence.
Are you afraid that elevating 1981, will hinder people from working on new and better solutions?

Best regards,