Fwd: HTTP redirect for HTTP Adaptive Streaming (HAS) in CDN use cases

[Resending as I have sent to the wrong list]


Hello ,

HTTP redirect, usually using 302 Found, is widely used in video CDN for
HTTP Adaptive Streaming (HAS) protocols, specifically for HLS and DASH.
Using HTTP redirect instead of the more commonly used delegation by CNAME
is a much more powerful and flexible solution.

At a high level, the required behavior is that after getting an HTTP
redirect to a playlist address that takes the client to a CDN cache, if the
playlist contains
relative references to the media segments, the client should be "sticky"
and request the subsequent media segments directly from the cache without
the need
for repeated redirects that would add undesired latency and harm QoE.
However, due to misinterpretations of the RFC in some cases, and
contradiction between this requirement and the existing RFC in other cases,
we face many
issues with clients that behave differently in the case of HTTP redirect,
when relative references are being used.
A discussion of this use case can also be found in section 2.2.1 of RFC6983
<https://tools.ietf.org/html/rfc6983#section-2.2.1>.

The Streaming Video Alliance (SVA) and DASH Industry Forum (DASH-IF) are
attempting to resolve these issues and create clear guidelines describing
how video players,
browsers and streaming applications should behave in such HTTP redirect
cases.

The attached I-D includes a detailed description of this issue, examples
with our understanding of the current behavior and proposals for
alternative approaches for solution.
We were hoping that the members of HTTPBIS working group could share their
views regarding the preferred  approach in order to resolve this issue.

If there is interest and some available time I can prepare a quick slide
deck for the httpbis meetings next week.


Best regards,
Ori



-- 

*Ori Finkelman*Qwilt | Work: +972-72-2221647 | Mobile: +972-52-3832189 |
orif@qwilt.com
-- 

*Ori Finkelman*Qwilt | Work: +972-72-2221647 | Mobile: +972-52-3832189 |
orif@qwilt.com
-- 

*Ori Finkelman*Qwilt | Work: +972-72-2221647 | Mobile: +972-52-3832189 |
orif@qwilt.com