一個連結IP群播和第二層群播的架構

Abstract

Multimedia applications, such as Video Conferences and Distance Learning, depend on "IP multicasting" technology. IP multicasting is an efficient multi-destinations and robust unknown-destinations delivery. Because of using class D IP addresses as Group IDs, IP multicasting can be regarded as Layer 3 Multicasting.However, IP multicasting is problematic in the Layer 2 environments（e.g. LANs）because multicast packets will flood switches. Solutions for this problem are Internet Group Management Protocol (IGMP) Snooping, Virtual LAN, and GARP Multicast Registration Protocol (GMRP). Refer to IGMP Snooping, IGMP version2 supports "specific group query" and version3 supports "source-filtering" to eliminate flooding. On the other hand, Virtual LAN eliminates flooding by splitting a physical broadcast domain into several lTaking advantage of "dynamic multicast filtering" ability provided by GMRP and "virtual router " capacity by the Direct IP Switch, we propose a Virtual Multicast Router architecture to combine IP multicasting and Layer 2 multicasting. Finally, Inter-Router Multicast Virtual LANs in Intranet, an application of this model, is presented to illustrate this model.