QUASIMODO: quality of service-aware multicasting over DiffServ and overlay networks

• Published in: IEEE network 2003-01, Vol.17 (1), p.38-45
• Main Authors: Bianchi, G., Blefari-Melazzi, N., Bonafede, G., Tintinelli, E.
• Format: Article
• Language: English
• Subjects: Availability; Diffserv networks; Dynamics; IP (Internet Protocol); IP networks; Links; Multicast; Multicast protocols; Multicasting; Network operating systems; Networks; Quality of service; Real time; Routing protocols; Telecommunication traffic; Testing; Traffic control; Unicast
• ISSN: 0890-8044; 1558-156X
• DOI: 10.1109/MNET.2003.1174176

Efficient delivery of real-time multicast traffic imposes on the underlying network infrastructure the burden of supporting quality of service. This can be quite a complex issue in a differentiated services IP network, especially if multicast users are allowed to join and leave the multicast tree dynamically. In fact, since DiffServ lacks explicit reservation states, a replicating node cannot test whether a corresponding reservation exists on an output link, and upon a dynamic join of a QoS multicast user, the DiffServ network lacks control functions to verify whether resources are available along the new path. We present a solution to support dynamic multicast with QoS over a DiffServ network. Our solution combines two ideas. First, resource availability along a new QoS path is verified via a probe-based approach. Second, QoS is maintained by marking replicated packets with a special DSCP (differentiated service code point) value before forwarding them on the QoS path.