Article · Wikipedia archive · Last revised Jun 21, 2026

Local Peer Discovery

The Local Peer Discovery protocol, specified as BEP-14, is an extension to the BitTorrent file-distribution system. It is designed to support the discovery of local BitTorrent peers, aiming to minimize the traffic through the Internet service provider's (ISP) channel and maximize use of higher-bandwidth local area networks (LANs).

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The Local Peer Discovery protocol, specified as BEP-14,1 is an extension to the BitTorrent file-distribution system. It is designed to support the discovery of local BitTorrent peers, aiming to minimize the traffic through the Internet service provider's (ISP) channel and maximize use of higher-bandwidth local area networks (LANs).

Local Peer Discovery is implemented2 with HTTP-like messages on User Datagram Protocol (UDP) multicast group 239.192.152.143:6771 (IPv4) or ff15::efc0:988f (IPv6)1 which are administratively scoped multicast addresses. It's similar to Simple Service Discovery Protocol but sends BT-SEARCH instead of M-SEARCH: 

BT-SEARCH * HTTP/1.1\r\n
Host: <host>\r\n
Port: <port>\r\n
Infohash: <ihash>\r\n
cookie: <cookie (optional)>\r\n
\r\n
\r\n


Since implementation is simple, Local Peer Discovery is implemented in several clients (μTorrent,3 BitTorrent/Mainline,4 MonoTorrent,5 libtorrent6 and its derivatives, Transmission,7 aria28). An alternative multicast peer discovery protocol based on ZeroConf is published as BEP 26 Zeroconf Peer Advertising and Discovery, but is not widely adopted since it is considered too complex9 in comparison.

References

References

  1. "BitTorrent Enhancement Proposal 14: Local Service Discovery". BitTorrent.org. 29 October 2015. Retrieved 17 September 2019.
  2. "Protocol Design Discussion » Local Peer Discovery Documentation". 2009-10-30. Retrieved 2009-12-12.
  3. "Announcements » μTorrent 1.7 Release Candidate 6". 2007-06-28. Archived from the original on 2012-03-08. Retrieved 2009-12-12.
  4. "BitTorrent User Manual". Archived from the original on 2009-12-27. Retrieved 2009-12-12.
  5. "MonoTorrent 0.80". Retrieved 2010-05-05.
  6. "libtorrent manual: features". Retrieved 2009-12-12.
  7. "Release Notes: Transmission 2.00". GitHub. 2010-06-15. Retrieved 2020-05-23.
  8. "Aria2 Manual: OPTIONS". Retrieved 2015-09-14.
  9. "Transmission Bug Tracker: ZeroConf Peer Advertising and Discovery". Retrieved 2016-10-26.