Re: QUIC use with multicast

[David Waring <[e-mail]>]

Hi Gyan,

You might want to look at
https://datatracker.ietf.org/doc/draft-pardue-quic-http-mcast/
which looks at using HTTP/3 in QUIC over IP multicast.

It not as simple as just using QUIC in multicast. As you point out, 
there are unidirectional streams, but these are encapsulated within a 
bidirectional QUIC session. The bidirectional nature is required to make 
the protocol reliable. Unfortunately bidirectional doesn't work well 
with multicast.

The draft above makes the stream truly unidirectional by removing the 
ack system on the QUIC multicast session, which removes the reliability, 
but also means that the session no longer needs to send anything back 
from receiver to sender. A separate bidirectional unicast session is 
used to fill in any gaps in the data streams received.

Another solution, which we considered as too complex at this stage, is 
to use multipath, with the unicast session being setup but using a 
second unidirectional multicast path to deliver the majority of shared 
content (live video stream for example). This would however require a 
separate packet number space for the multicast stream in order to share 
that path between multiple connections, which complicates the ack system 
and isn't catered for in the current incarnation of QUIC. But this is 
something we may look into in the future.

Regards,
David

On 17/01/2020 02:05, Gyan Mishra wrote:
> 
> QUIC WG
> 
> Has anyone ever tried using QUIC with multicast RTP UDP streamed using 
> QUIC transport.
> 
> Multicast has always been problematic with use on the internet MBONE and 
> even on intranets due the unreliable UDP RTP transport for MPEG4 MPEG-TS 
> and even newer protocols MPED-DASH abs and HLS multicast has struggled 
> with using UDP transport.
> 
> Multicast has thus required stringent end to end QOS in profile 
> guaranteed scheduling bandwidth hop by hop PHB to ensue no drops to 
> avoid dropping of I frame resulting in client frozen window and buffering.
> 
> Since QUIC is a secure reliable transport and supports unidirectional 
> flows it would be a perfect fit for multicast.
> 
> This would be a game changer for multicast as over the internet which 
> you don’t have any QOS guarantee.
> 
> Kind regards
> 
> Gyan
> 
> 
> -- 
> 
> Gyan  Mishra
> 
> Network Engineering & Technology
> 
> Verizon
> 
> Silver Spring, MD 20904
> 
> Phone: [phone]
> 
> Email: [e-mail] <mailto:[e-mail]>
> 
> 
> 
-- 
David Waring, Project Software Engineer, BBC Research & Development