Fwd: New Version Notification for draft-pardue-httpbis-priority-order-00.txt

Hi folks,

Please see the attached notice for a proposed send-order parameter for
extensible priorities. Recall that the recommended scheduling guidance [1]
is that non-incremental responses of the same urgency be served in stream
ID order. This closely maps to typical web cases where a user agent has a
good chance of dispatching requests in a sensible order.

However, there are some use cases where stream ID order might not be
optimal. A late discovered item could be more valuable to receive than
others that are being queued up to serve - effectively getting HoL blocked
in the sender's scheduler. While it might be possible to work around that
by smarter or more elaborate use of urgencies, there are some factors and
constraints that make that difficult in practice.

An alternative to juggling urgencies is the send-order parameter, with the
idea being to enhance the current scheduling guidance. The scheduler would
effectively operate over three groups per urgency level in this order:

1) The non-incremental send-order group, served in send order
2) The non-incremental group, served in stream order
3) The incremental group, served in round-robin fashion

One example of use case for this parameter is a LIFO style media streaming
case (such as those being discussed in the Media over QUIC WG), where the
last media items are more important than early ones. If all items have the
same urgency, LIFO can be trivially achieved by incrementing the send-order
parameter for each one and effectively never giving the scheduler group 2
or 3.

Another example use case is explicitly letting an item jump the group 2
queue by providing a send-order of any value. This could potentially be
most useful for server-side overrides, whereby it is difficult to exchange
connection-local stream IDs in a way that would allow an origin behind the
proxy to make good decisions. Instead, they could rely on a fairly simple
send-order mapping table to influence behaviours downstream.


[1] - https://www.rfc-editor.org/rfc/rfc9218.html#name-server-scheduling

---------- Forwarded message ---------
From: <internet-drafts@ietf.org>
Date: Sun, Mar 26, 2023 at 6:15 AM
Subject: New Version Notification for
To: Lucas Pardue <lucaspardue.24.7@gmail.com>

A new version of I-D, draft-pardue-httpbis-priority-order-00.txt
has been successfully submitted by Lucas Pardue and posted to the
IETF repository.

Name:           draft-pardue-httpbis-priority-order
Revision:       00
Title:          HTTP priority order extension
Document date:  2023-03-26
Group:          Individual Submission
Pages:          8

   The send-order parameter for the HTTP extensible prioritization
   scheme allows explicit ordering indication independent of request
   order.  This can be used to as an additional input signal to
   scheduling decisions, to support alternative sending behaviors.

The IETF Secretariat

Received on Sunday, 26 March 2023 05:54:49 UTC