Document Type

Technical Report


Computer Science and Engineering

Publication Date






Technical Report Number



High-bandwidth multimedia applications pose new challenges to error control. These include the support of error control for Continuous Media (CM) streams and the scalable support of error control in multipoint applications where the number of participants is large. Current error control mechanisms provide no support for the above applications. In this report we present new error control mechanisms that provide the required support. Continuous media applications have strict timing requirements which greatly affect recovery. To support continuous media applications we have designed and implemented a point-to-point error control mechanism which features the following: (1) selective repeat retransmission, (2) conditional retransmission, (3) playout buffering to increase the time available for recovery, (4) gap-based rather than timer-based loss detection to reduce loss detection latency, and (5) data integrity information delivery to the application. We present our design, implementation and evaluation plans. Multipoint applications with a large number of participants do not scale well because of implosion. Implosion control can be performed by the sender, the receivers, or via a hierarchy. Sender-controlled implosion is appropriate when: (a) receiver anonymity and privacy is required, (b) receivers cannot buffer and retransmit data, and (c) in one-to-many connections on connection-oriented networks where receivers are isolated from each other. In hierarchical implosion control, the receivers are structured as a virtual tree with the sender at the root. The scope of receiver messages is restricted between children and their parents. We have designed and are investigating new sender-controlled and hierarchical implosion control mechanisms. We present our designs and our plans to investigate the effecrtiveness and associated trade-offs of the mechanisms by using implementation and simulation in our ATM testbed.


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