Bandwidth Management for Intranets Using Multicast Firewalls

Multimedia applications utilizing multicast transmission techniques are becoming prevalent as the number of users and types of applications proliferate. Nonetheless, the deployment of such applications throughout an Intranet is constrained by the lack of multicast capable routers and the inability to protect the network from being swamped by multicast traffi

Bandwidth Management for Intranets Using Multicast Firewalls

Multimedia applications utilizing multicast transmission techniques are becoming prevalent as the number of users and types of applications proliferate. Nonetheless, the deployment of such applications throughout an Intranet is constrained by the lack of multicast capabl e routers and the inability to protect the network from being swamped by multicast traffic. Multicast firewalls are designed to overcome these limitations. The roles of a multicast firewall are to: * Perform multicast packet forwarding in place of tunneling across existing routers for an Intranet * Perform packet replication optimization via multicast group management (multicast spanning tree management) * Perform subnet bandwidth management, by assigning priorities to multicast addresses and filtering (dropping) packets for each group according to specified criteria This paper outlines requirements for multicast firewalls, as well as describes an implementation of a dual-LAN multicast firewall prototype implemented using Linux. Keywords Multicast, Firewall, Bandwidth Management, Intranet, H.323, Multimedia Applications. INTRODUCTION The development of multicasting as the vehicle for multimedia content delivery has resulted in the proliferation of new applications that take advantage of the bandwidth optimizati on of multicast transmission. Nonetheless, enabling such applications to operate in an Intranet environment necessitates the use of multicast capable routers that are still in limited use. Multicast tunneling, while effective, introduces additional bandwid th requirements to support the following environment [2]