%T Improving TCP/IP Multicasting with Message Segmentation
%A  Hans Henrik Happe,  Brian Vinter
%E  Jan F. Broenink,  Herman Roebbers,  Johan P. E. Sunter, Peter H. Welch,  David C. Wood
%B Communicating Process Architectures 2005
%X Multicasting is a very important operation in high
   performance parallel applications. Making this operation
   efficient in supercomputers has been a topic of great
   concern. Much effort has gone into designing special
   interconnects to support the operation. Today&\[sh]8217;s
   huge deployment of NoWs (Network of Workstations) has
   created a high demand for efficient software\-based
   multicast solutions. These systems are often based on
   low\-cost Ethernet interconnects without direct support for
   group communication. Basically TCP/IP is the only widely
   supported method of fast reliable communication, though it
   is possible to improve Ethernet performance at many levels
   &\[sh]8211; i.e., by\-passing the operating system or using
   physical broadcasting. Low\-level improvements are not
   likely to be accepted in production environments, which
   leaves TCP/IP as the best overall choice for group
   communication. In this paper we describe a TCP/IP based
   multicasting algorithm that uses message segmentation in
   order to lower the propagation delay. Experiments have shown
   that TCP is very inefficient when a node has many active
   connections. With this in mind we have designed the
   algorithm so that it has a worst\-case propagation path
   length of O(log n) with a minimum of connections per node.
   We compare our algorithm with the binomial tree algorithm
   often used in TCP/IP MPI implementations.