[Ecn-sane] [tsvwg] Compatibility with singlw queue RFC3168 AQMs

[Jeremy Harris]

On 07/08/2019 11:06, Mikael Abrahamsson wrote:
> I also encourage if we can reach overall consensus that transports
> should take into account that packets can be re-ordered and what
> timescales would be acceptable for this to happen (1ms? 10ms? 100ms?
> Even more? Less? Not at all?)

The major issue I see is that the interface between transport and
its client layer needs to become more complex for that.

I could, for example, imagine a pure (FTP-complexity) file transfer
application over TCP being able to receive out-of-order received
TCP segments and hand them direct to the kernel using pwrite
(assuming TCP SACK in use).  But the socket interface would need
to present sequencing information along with the segments; it being
no longer implied by the sequence of satisfied reads.

The timescale for acceptable re-ordering for that case is "indefinite".
But it's only one case, and a pretty limited one.

-- 
Cheers,
  Jeremy