Acm Sigcomm –101– Computer Communication Review 8 Related Work Acm Sigcomm –100– Computer Communication Review 7 Hierarchical Multicast Routing 6 Link-state Multicast Routing 5.4 Reverse Path Multicasting (rpm)

The Ethernet: a local area network; data link layer and physical layer specifications , version 1.0. [23] R. Perlman. An algorithm for distributed computation of a spanning tree in an extended LAN. within the subdomain a special " wild-card " group that all superdomain routers may join; the changes to each algorithm to support wild-card groups are straightforward. A variety of algorithms for multicast routing in store-and-forward networks are described by Wall [26], with emphasis on algorithms for constructing a single spanning tree that provides low average delay, thereby striking a balance between opposing goals of low delay and low network cost. Frank, Wittie and Bernstein [10] provide a good survey of multicast routing techniques that can be used in internetworks, rating each according to such factors as delay, bandwidth, and scaleability. Sincoskie and Cotton [25] propose a multicast routing algorithm for link-layer bridges which supports a type of group in which all senders must also be members of the group. Such groups are acceptable for some applications, such as computer conferencing, but are not well suited to the common client/server type of communication where the (client) senders are generally not members of the (server) group and should not receive packets sent to the group. 9 Conclusions We have proposed a number of algorithms for routing multicast datagrams in internetworks and extended LANs. The goal of each algorithm is to provide a mul-ticast service that is as similar as possible to LAN mul-ticasting, so that applications that currently benefit from LAN multicasting may be moved to a multiple-network environment with little or no change. In particular, we have concentrated on low delay multicasting, in order to minimize the effect of going from the LAN environment to a store-and-forward environment. Different multicast routing algorithms were developed as extensions to three different styles of unicast routing: the single-spanning-tree routing of extended LAN bridges, and the distance-vector and link-state routing commonly used in internetworks. These different routing styles lead to significantly different multicast routing strategies, each exploiting the particular protocols and data structures already present. For most of the algorithms, the additional band-width, memory and processing requirements are not much greater than those of the underlying unicast routing algorithm. In the case of distance-vector routing, we presented a range of multicast routing algorithms based on Dalal and Metcalfe's reverse path forwarding scheme, providing increasing " precision " of delivery (flooding, broadcasting, truncated broadcasting …