Andrew Krowczyk & Vinod Kumar 
Pro .NET 1.1 Network Programming [PDF ebook] 

Networking is one of the core tasks of enterprise-level programming, and this book covers key concepts, like network programming in .NET with C#, and building network-based applications in .NET. You will gain confidence to use the classes shipped with .NET, and eventually implement your own application-level protocols.The text first overviews important background material, like physical network architecture, network protocols, the Open Systems Interconnection (OSI) model, streams in .NET, and stream access. Also covered in detail: socket programming complete with introduction, and descriptions for use in .NET.Finally, the book explores Internet programming, with a look at HTTP the underlying protocol of e-mail and Internet. By the end of the book, you will also have learned to secure network communications in .NET.