Abstract- Host mobility is becoming an important issue due to the recent proliferation of notebook and palmtop computers, the development of wireless network interfaces, and the growth in global internetworking. This paper describes the design and implementation of a mobile host protocol, called the Internet Mobile Host Protocol (IMHP), that is compatible with the TCPDP protocol suite, and allows a mobile host to move around the Inter-net without changing its identity. In particular, IMHP provides host mobility over both the local and wide area, while remaining transparent to the user and to other hosts communicating with the mobile host. IMHP features route optimization and integrated authentication of all management packets. Route optimization allows a node to cache the location of a mobile host and to send future packets directly to that mobile host. By authenticating all management packets, IMHP guards against possible attacks on packet routing to mobile hosts, including the interception or redirection of arbitrary packets within the network. A simple new authentication mechanism is introduced that preserves the level of security found in the Internet today, while accommodating the transition to stronger authentication based on public key cryptog-raphy or shared keys that may either be manually administered or provided by a future Internet key management protocol. I.

New distributed computing applications are driving the development of more specialized protocols, as well as demanding greater control over the communication substrate. Here, a network subsystem that supports modular, finegrained construction of high-level protocols such as atomic multicast and group RPC is described. The approach is based on extending the standard hierarchical model of the x-kernel with composite protocols in which micro-protocol objects are composed within a standard runtime framework. Each micro-protocol realizes a separate semantic property, leading to a highly modular and configurable implementation. In contrast with similar systems, this approach provides finer granularity and more flexible inter-object communication. The design and prototype implementation runing on Mach are described. Performance results are also given for a micro-protocol suite implementing variants of group RPC. 1 Introduction Network protocols that are implemented at high levels of the pro...

One of the most important issues affecting host mobility is the location and routing scheme that allows hosts to move seamlessly from one site to another. This paper presents a method that exploits the locality properties of a host's pattern of movement and access history. Two concepts, "local region" and "patron service", are introduced based on the locality features. For each mobile host, the local region is a set of designated subnetworks within which a mobile host often moves, and the patrons are the hosts from which the majority of traffic for the mobile host originated. These are used to confine the effects of a host moving, so location updates are sent only to its local area, and to those source hosts which are most likely to call again. Our scheme has the advantages of limiting location updates, and providing optimal routing, whilst increasing network and host scalability.

"Mobile Computing" has been a buzzword in the area of computer communications. A technology vital to mobile computing is how to communicate with mobile hosts. This paper proposes a protocol, Virtual Internet Protocol (VIP), that allows hosts to move transparently within the Internet. VIP is defined as an instance of the virtual network protocol, the general protocol supporting mobile hosts. The virtual network protocol is based on the concept of a virtual network and the propagating cache method. VIP is scalable to the total number of mobile hosts and the scale of the Internet, is free from routing loops, and tolerant of loss of control packets. VIP is currently running on operating systems based on 4.3BSD UNIX. The VIP overhead is negligible when compared with IP.

This paper compares four recent proposals for mobile host protocols (MHPs) that are compatible with the TCP/IP protocol suite. A set of requirements for an MHP is proposed and it is observed that while all proposals perform the basic task none of the proposals entirely satisfy the requirements. 1. Introduction

Host mobility is becoming an increasingly important feature with the recent arrival of notebook and palm top computers, the development of wireless network interfaces and the implementation of the global network. This paper describes and compares three proposals from Sony, IBM and Columbia University for mobile host protocols (MHP) that are compatible with the TCP/IP protocol suite. A set of basic requirements for a MHP are also suggested and it is observed that none of the three proposals entirely satisfies these requirements. Each proposal has faults in their implementation of mobile network layer functionality. Moreover, it is noted they do not address problems that must be solved in both higher and lower layers. Key Words: Mobile Protocols, Wireless Networks, Networks, IP 1 Introduction Computers are no longer large, expensive, and nonportable. Recent developments make it possible to buy inexpensive notebook and palm top computers that are both portable and extremely powerful. As a...

This thesis explores the provision of End System (ES) mobility on large, datagram-based, internetworks.

This paper presents a novel routing scheme for wireless mobile networking which is adaptive to the mobile traffic patterns. We propose a concept called "friend network" to accommodate the need for effective routing information update. Our routing scheme has the advantages of minimizing network bandwidth consumptions, providing optimal routing, and addressing network security concerns at the same time. 1.0 Introduction The advances in computing technology have produced miniaturized computers such as notebook and palmtop computers. Meanwhile, the rapid expansion of wireless communication technologies such as cellular network, wireless LAN are making it possible to support universal network connectivity for mobile computers. Such universal network connectivity offers great promises for general purpose mobile computing. However, network connection between mobile computers presents an entirely different challenge compared to that of the traditional fixed static network. One of the most imp...

"Mobile Computing" is a buzz word in the area of computer communication nowadays. An important technology in mobile computing is how to communicate with mobile hosts. We introduced Virtual Internet Protocol (VIP)[9] to achieve host migration transparency. Although VIP works correctly in a pure VIP environment, there are two major problems when VIP is used in existing IP networks: 1) backward compatibility with IP and 2) remaining obsolete cache entries. This paper enhances VIP to solve these problems. In enhanced VIP, the VIP header format is redesigned so that enhanced VIP is fully compatible with IP. To solve the problem of obsolete cache entries, "temporary proxies" and "two-phase cache deletion " are employed. Enhanced VIP is running on SONY NEWS workstations and PC/AT clones. Its overheads have been slightly improved though several functions such as two-phase cache deletion have been added. I. Introduction Mobile telephones have become popular and several kinds of future telepho...

This paper proposes a network architecture to support mobile communication in a large university campus. The design allows each mobile host to maintain transport connectivity while roaming freely in the campus. Called Crosspoint, the design combines wireless local-area network (LAN) technology with high-speed Asynchronous Transfer Mode (ATM) switching technology. The combination provides a wireless communication system with sufficient aggregate bandwidth to handle massive, synchronized movements of mobile hosts. Furthermore, the design requires no modification to conventional network software on mobile hosts, stationary hosts, or existing IP routers. We have implemented a prototype of the Crosspoint design. This paper also describes the basic protocols used in the implementation. 1 Introduction Recent advances in personal computing and wireless LAN technologies have resulted in affordable laptop and palmtop computers with wireless networking capability. A computer with wireless A Po...