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In computer networking, the Reliable User Datagram Protocol (RUDP) is a transport layer protocol designed at Bell Labs for the Plan 9 operating system. It aims to provide a solution where UDP is too primitive because guaranteed-order packet delivery is desirable, but TCP adds too much complexity/overhead. In order for RUDP to gain higher quality of service, RUDP implements features that are similar to TCP with less overhead.
Implementations
[edit]In order to ensure quality, it extends UDP by means of adding the following features:
- Acknowledgment of received packets
- Windowing and flow control
- Retransmission of lost packets
- Over buffering (Faster than real-time streaming)
RUDP is not currently a formal standard, however it was described in an IETF Internet Draft in 1999.[1] It has not been proposed for standardization.
Cisco RUDP
[edit]Cisco in its Signalling Link Terminals (either standalone or integrated in another gateway) uses RUDP for backhauling of SS7 MTP3 or ISDN signaling.
- RUDP v0 (no checksums) is used for SS7 MTP3 backhaul.
- RUDP v1 (with checksum) is used for ISDN PRI backhaul.
The versions are mutually incompatible and differ slightly from the IETF draft.[citation needed] The structure of the Cisco Session Manager used on top of RUDP is also different.
Microsoft R-UDP
[edit]Microsoft introduced another protocol which it named R-UDP and used it in its MediaRoom product (now owned by Ericsson) for IPTV service delivery over multicast networks. This is a proprietary protocol and very little is known about its operation. It is not thought to be based on the above referenced IETF draft.[2]