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Scalability improvement of the real time control protocol

Research output: Contribution to journalJournal articlepeer-review

<mark>Journal publication date</mark>10/02/2005
<mark>Journal</mark>Computer Communications
Issue number2
Number of pages14
Pages (from-to)136-149
Publication StatusPublished
<mark>Original language</mark>English


Scalability problems arise when the Real Time Control Protocol (RTCP), which is the control protocol of the Real-time Transport Protocol (RTP), is used in large multicast groups. The problems include: increased feedback delay, increased storage state at every member, and ineffective RTCP bandwidth usage.

We have designed a Scalable RTCP (S-RTCP) which is based on a hierarchical structure in which members are grouped into local regions. For every region, there is an Aggregator (AG) which receives the feedback Receiver Reports (RRs) sent by its local members. The AG summarizes important information in the RRs, derives some statistics, and sends them to a Manager. The Manager performs additional statistical analysis to monitor the transmission quality and to identify regions suffering massively from congestion.

A simulation of S-RTCP using the Network Simulator (NS) showed that S-RTCP alleviates some of the RTCP scalability problems and makes effective use of RRs. Consequently, the feedback provides timely and useful QoS information required for network monitors and for adaptive applications. Details of the simulations and performance analysis are presented and described which show the advantages of using S-RTCP over the original RTCP.