Fast Group Management in IGMP
Luigi Rizzo · 1998
The ability to control quickly the expansion/reduction of the multicast distribution tree is central in some recent proposals for multicast congestion control. At the lowest level, these operations are controlled by the IGMP protocol. With the current specification of the protocol, IGMP takes a few seconds to stop distribution of a group after a request. This reduces the effectiveness of congestion control mechanisms based on this feature. In this paper we propose a mechanism to make the LEAVE operation act instantaneously, basing on prediction techniques similar to those used in processors for optimizing jump performance. The proposed mechanisms acts on the router side only, and it is fully compatible with the existing IGMP protocol. An implementation of the mechanisms described in this paper has been included in the latest mrouted3.9 sources and is available from the author. 1 Introduction The IP multicast infrastructure (MBone) has been successfully used in recent years to support ...