Muse-IP: A Network Layer Protocol for Large
Distributed Systems with Mobile Hosts
Fumio Teraoka, Yasuhiko Yokote, and Mario Tokoro1
tel: +81-3-448-4380 fax: +81-3-448-4273
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Sony Computer Science Laboratory Inc.
3-14-13 Higashigotanda, Shinagawa-ku, Tokyo, 141 JAPAN
In spite of the fact that the works about distributed operating systems has been very active, it seems that the importance of network layer protocols in distributed environments is scarcely recognized. This paper describes the basic design of the Muse-IP, a network layer protocol, which is suitable for large distributed systems with mobile hosts such as lap-top computers. The Muse-IP is based on ISO CLNP for the sake of compatibility and adds some features to it. The Muse-IP exploits the interface information to eliminate redundant processing. The addressing scheme of the Muse-IP can make routing functions easier and support mobile hosts in the internet. The Muse-IP can also provide realtime communications by predicting the communication time between source and destination hosts. The Muse-IP is being implemented in the Muse operating system as a network layer protocol.
Several distributed operating systems such as V-system, DASH, Sprite, and Mach, have been designed and implemented. Among those operating systems, V-system developed their own transport layer protocol, VMTP[Cheriton 86], and Sprite implemented their own network protocol[Welch 86]. These two protocols are suitable for applications using remote procedure calls. DASH proposed a new communication abstraction, channels[Anderson 89] which provide communication paths with user desired qualities. Although new protocols for the transport layer and new concepts of communications have been discussed, the discussion about network layer protocols suitable to large distributed systems is scarcely heard. Network layer protocol is very important on developing large distributed systems because network layer protocols have responsibility to control the whole internet. That is, in the whole internet, how addresses of hosts are assigned, how routing of packets is done efficiently, how reliable communications are provided, how real-time communications are supported, etc., are responsibilities of network layer protocols.
DARPA Internet Datagram Protocol (DARPA-IP) has gained the position of a de facto standard of network layer protocols. ISO has also recommended a network layer protocol, connectionlessmode network layer protocol (ISO CLNP)[ISO 86b] based on datagram communications. They have several shortcomings such that they can't support mobile hosts and they can't provide real-time communications.
The Muse Internet Protocol (Muse-IP) is designed to support communications in large distributed systems with mobile hosts as depicted in Figure 1. The transport layer can provide connectionmode and connectionless-mode communications to upper layers efficiently by using functions provided by the Muse-IP. Real-time communications are supported by communication time estimation and specification of priority. The Muse-IP is being implemented on the Muse operating system as a network layer protocol.
1also with Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama, 223 JAPAN