UDP vs TCP : streaming content

I agree with everything that Mick has said, but would like to add the following: the way WebRTC is set up, you can prioritise UDP over TCP so that you can get flexibility of UDP, but when UDP is blocked (hotels, government institutions etc), you can offload to TCP. We have implemented this at LiveSwitch and it seems to work well in the context of live meetings and broadcasts.

TCP vs UDP for streaming and real time communications is a long running and ongoing discussion.

I suspect you'll find there is no single 'right' answer.

In very high level terms UDP does seem a better match for media streaming but there are many reason why TCP is also used and is probably most common at this time for end user OTT video delivery.

One of the reasons is that TCP and HTTP traffic are 'accepted' by many networks and firewalls while UDP traffic often will be subject to restrictions.

Another reason may be that many of the largest streaming services were initially VOD rather than Live, and quality and lack of buffering were bigger drivers than latency, so the extra overhead of TCP was offset by its greater perceived reliability.

As Live streaming becomes more and more important the landscape is evolving with much focus on low latency HLS and DASH (TCP) and on applying technologies like webRTC (UDP) to streaming. At the moment the momentum seems to still be with low latency version of the traditional TCP streaming protocols but that could change over time.

Its worth noting too that UDP streaming is used extensively today also, especially in the backend with contribution and post production feed using the SRT protocol and in operators IPTV multicast backbones networks.