Re: [Spud] updated draft PLUS charter, rev. 1 June

[Brian Trammell <[e-mail]>]

> On 08 Jun 2016, at 06:27, Brian Trammell <[e-mail]> wrote:
> 
> Hi Joe, all,
> 
> Inline...
> 
>> On 08 Jun 2016, at 00:35, Joe Touch <[e-mail]> wrote:
>> 
>>> On 6/7/2016 3:19 PM, Tom Herbert wrote:
>>>> On Tue, Jun 7, 2016 at 3:09 PM, Joe Touch <[e-mail]> wrote:
>>>> 
>>>>> On 6/7/2016 3:05 PM, Tom Herbert wrote:
>>>>> The proper architectural solution is to place network layer
>>>>> information like what is being proposed in the network layer :-)
>>>>> Trying to make a network layer out of UDP fails on several accounts
>>>>> (fragments don't contain UDP headers, ports do not have global
>>>>> meaning, etc.). IPv6 extension headers are designed for carrying
>>>>> information like this, I really hope there is more investigation as to
>>>>> whether they are workable for signaling.
> 
> I know that Jen Linkova has done some measurement work on this with respect to on-path treatment; I forget the conclusions. Of course that leaves the question of userspace implementation open.

On the question of path transparency to DO extension headers in V6, see this talk from IEPG at IETF91:
http://iepg.org/2014-11-09-ietf91/iepg-ietf91-ipv6-ehs-in-the-real-world-v3.0.pdf (thanks Jen Linkova and Fernando Gont), the takeaway from which is that the minimum observed drop rate of small (8-byte) DO EH on UDP packets is about 6%.

There was also Geoff Huston's IPv6 WG presentation at RIPE a couple of weeks ago: https://ripe72.ripe.net/presentations/67-2016-05-23-bigipv6.pdf: in addition to a nice summary of why ICMP-as-is is broken, he found an upper bound of 16% on in-network fragmentation EH drops.

So the situation with IPv6 EH seems to be slightly worse than the situation with UDP, probably harder to diagnose at runtime, and requires kernel support. So while I agree this is architecturally cleaner, I'm skeptical that it's as deployable as a UDP encapsulation-based approach.

Cheers,

Brian