Douglas Comer, author of many successful books and an expert in computer networking, builds a comprehensive picture of the technologies that enable the Internet to provide application services such as web browsing and instant messaging.

The book offers an excellent overview, covering everything from Internet applications to the lower levels of packet transmission. It describes how protocols are organized into layers and explains how the services of one layer are used by the immediately higher layer.

Fully updated, the book also includes the following:
· UDP: User Datagram Protocol: Presents the end-to-end user datagram protocol and its usage. Although once of secondary importance, UDP is now the basis for broadcasting and multicasting applications, as well as new applications for audio and video transmission.
· Network Address Translation: Explains how NAT technology overcomes Internet limitations regarding the sharing of a single IP address by multiple computers, which is extremely important in home installations and small business setups.
· IP Telephony (VoIP): Examines the exciting application of the Internet - making telephone calls over the Internet (VoIP). It describes the competitive standards of IP telephony, including protocols such as H.323, Session Initiation Protocol (SIP), and Megaco. It also presents an example of a SIP session.

The book is accompanied by a multimedia CD-ROM, with animated images, packet traces, over 200 photographs of networking equipment, code from the book, and copies of protocol standards.