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FalconUDP is an application level protocol for sending and receiving small messages (one up to about one thousand bytes) frequently (once a minute to hundreds of times a second) to and from one or many connected peers. It has been implemented on top of the Internet User Datagram protocol (UDP).

This is the official .NET implementation, implemented as a .NET 4.0 Class Library: FalconUDP.dll. Throughout this site "FalconUDP" is used interchangeably to refer to the protocol or this .NET implementation.

FalconUDP was developed by Gnomic Studios for their multiplayer game Square Heroes: http://www.squareheroes.com, check it out to see FalconUDP perform.

Features

• Authentication and connection orientated. FalconUDP only communicates with previously authenticated peers.
• In-order and/or reliable messages. Messages can be sent in-order, reliably, both in-order and reliable, or without any reliable and in-order checking and controls. Duplicates are always detected and dropped.
• Minimal data overhead. FalconUDP adds minimal data to the user-application's data to be sent and received "on the wire" and includes support for "packing" additional user-application packets into existing outgoing messages.
• Latency estimation. FalconUDP measures round-trip-times from sending reliable messages till receiving the corresponding ACKnowlodgment, providing one way latency estimation to each connected peer.
• Any Topology. User-applications can use their own logical network topology such as Server-Client or Peer-to-Peer, since a "Falcon peer" can have one or more connected peers.
• Discovery. FalconUDP peers can "discover" other FalconUDP peers on the same subnet (if a FalconUDP peer is set to accept discovery requests and optionally the request has a valid token).
• NAT Traversal. Two FalconUDP peers behind NAT(s) can establish a connection with each other after connecting to third publically accessible server to negotiate the connection.
• Minimal garbage. FalconUDP makes extensive use of memory management techniques to avoid creating garbage such as: pooling objects, segmenting buffers from large ones (to prevent heap memory fragmentation) and copying data directly into and out of buffers.
• Statistics. Total bytes per second sent and received to/from all remote peers.
• Simulate latency, jitter and packet loss options.

Limitations

• Hard max limit of ~1400 bytes per message. FalconUDP is designed for small messages, not a stream of bytes - use TCP for that.
• Currently only IPv4 supported.
• No Congestion Control. FalconUDP provides no in-built congestion control.†
• No Encryption. FalconUDP has no in-built encryption.†

† User-applications can use their own implementation before sending and after receiving data using the library's API