Technical overview of LAN interconnection

Books Technical overview of LAN interconnection lnternetworking: A guide to network communications; LAN to LAN; LAN to WAN by Mark A Miller, Prentice Hall. UK, 1991, £22,95. 425 pp The 1980s were the LAN's years, in the sense that after a long period of study and development, the business community believed that LANs were installable, configurable and maintainable by network managers. In the 1990s another challenge has arisen: how do we connect dissimilar LANs, physically located in remote sites, working under different operating systems'? The era of internetworking is born. This challenge involves many problems: what type of line, analogue or digital, should be utilized'? What kind of software platform should be used, etc? This book offers a technical overview on the variety of aspects involved in the problem of LAN interconnection. It examines, in a practical context, a set of possible approaches and solutions, both t¥om the hardware and software points of view. The purpose of the book is to provide a comprehensive guide to network designers, managers and administrators who need to face the

internetworking of their own LANs with dissimilar, remote networks. As the book is not a didactic text, its reading requires previous specific knowledge of the subject, at least as far as LAN operation is concerned. Some concepts are supposed to be already known, or are only briefly explained. However, reading is simplified by figures, block diagrams and architectural schemes which help to fully explain the characteristics of solutions under discussion. The book is structured according to the OSI architecture, working from the physical layer through to the application layer. Much space is given to standardization aspects. providing a useful insight into the complex world of standards and recommendations. This chapter includes contributions from ANSI, IEEE and ISO. and in particular, it discusses the OSI internetworking protocols, the 802 series LANs, and contains a brief presentation of FDD! and ARCNET. Different sections focus on LANLAN and LAN-WAN internetworking. In the first case, a local internetwork (not wide area) is assumed, and the various dedicated devices, repeaters, bridges, brouters and routers are presented. The

reciprocal differences are clearly explained and their performance emphasized. As far as wide area interconnections are concerned, the characteristics of the various transmission facilities (analogue switched or leased lines, digital leased lines) and of the public data networks (e.g.X.25) are presented and discussed. A brief account of emerging technologies (i.e. frame relay, SONET, ISDN) is also given. Moreover, a set of devices which can be utilized with the various transmission facilities are studied. The second part of the book is dedicated to protocol and software aspects. OSI network and transport layer functionalities are discussed, together with features of the X.25, TCP/IP and XNS protocols. The concluding chapters are devoted to the internetworking and interoperability functions included in the most popular networking software (Apple Computer's Apple Talk, Sitka Corporation's TOPS, Novell's NetWare), and to reviews of several gateway products that connect LANs to other LANs and LANs to microcomputers. A checklist for internetwork implementations concludes the book.

Dr Marco Listanti Universitd di Roma 'La Sapienza' Roma, Italy

computer communications volume 16 number 4 april 1993

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