For delivering video over internet TCP must be used. When UDP is used developers end up re-implementing packet re-transmission, for eg. Bittorrent p2p live protocol. "If you use TCP, the OS must buffer the unacknowledged segments for every client. This is undesirable, particularly in the case of live events". This buffer must exist in some form.
UDP BitTorrent Will Destroy The Interwebs! - ..says According to posts at the uTorrent forum, the new version lays uTP, the micro transport protocol, on top of UDP, which provides for better flow control and prevents the kind of TCP RST packet bep_0015.rst_post - BitTorrent This overhead can be reduced significantly by using a UDP based protocol. The protocol proposed here uses 4 packets and about 618 bytes, reducing traffic by 50%. For a client, saving 1 kbyte every hour isn't significant, but for a tracker serving a million peers, reducing traffic by 50% matters a lot. bep_0003.rst_post - BitTorrent BitTorrent is a protocol for distributing files. It identifies content by URL and is designed to integrate seamlessly with the web. Its advantage over plain HTTP is that when multiple downloads of the same file happen concurrently, the downloaders upload to each other, making it possible for the file source to support very large numbers of downloaders with only a modest increase in its load.
Which TCP and UDP Port used by uTorrent? - General
tcp/udp torrents - LinuxQuestions.org
TCP: UDP: BitTorrent part of full range of ports used most often: Unofficial: 7000: TCP : Default for Vuze's built in HTTPS Bittorrent Tracker: Unofficial: 7001: TCP : Default for BEA WebLogic Server's HTTP server, though often changed during installation: Unofficial: 7002:
Aug 22, 2009 Does BitTorrent use TCP or UDP? - Quora BitTorrent uses both TCP and UDP, or should I perhaps say mainly TCP, for loading chunks of data between peers of a torrent session, but UDP between peers and the special supervising host called a tracker. That is, UDP is only used where it fits its purpose, for signaling and synchronization. Micro Transport Protocol - Wikipedia