Multicast traffic % in enterprise network ?

Brandon Butterworth brandon at
Fri Aug 10 12:30:29 UTC 2018

On Fri Aug 10, 2018 at 08:44:55AM +0100, Jethro R Binks wrote:
> In terms of other Internet use, the BBC recently published this white 
> paper on the R&D efforts with HTTP Server Push/QUIC, part of which 
> describes an "experimental IP multicast profile of HTTP over QUIC".

We're doing this as part of our work on moving the entirety of
broadcast, from camera to viewer, to IP. The broadcast industry is
going this way now (visit IBC or NAB and see) so you'll see plenty of
multicast inside their networks

I've kept out of the multicast hate fest, it's a tool and some tools
work better in some situations than others, some may be a bit old and

I don't think banishing multicast is the answer. It would be better to
fix the problems instead, if we don't want to sustain the content based
balkanisation of the internet by content rights holders and eyeball
networks that support them to exlude competition.

Internet VOD is huge but there is little linear TV. VOD traffic is
driving standards development not linear TV, so there is no demand to
fix inter domain multicast. We think our iPlayer VOD service traffic is
quite large but it is only 5% of our viewing so linear TV is not dead
yet, especially for major events. We could scale our CDNs for this but
multicast does it more efficiently in some networks.

Our aim with MPEG-DASH is to have one standard for uni and multicast
streaming where clients transparently use whichever works. If an edge
network wishes to use multicast, as many do for IPTV, they can but they
may have to use unicast from the origin, we didn't want to be delayed
for another 10 years waiting for other networks to turn it (back) on.
The edge network does not have to roll out multicast 100% as it will
just be used wherever it happens to have been deployed.

There have been standards for this, usually with tunnels. Using the
same DASH stream format means it's simpler to do transparently this way
giving networks more flexibility to handle the capacity issues when we
do a World Cup in IP only.

The latency problem remains, people don't like hearing the goal cheers
through the wall and waiting for it to appear on their screen.
Sometimes not all new standards, forcing video over HTTP rather than
RTSP, are progress.


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