Overview

I have been accused of having an unhealthy preoccupation with Web servers, to the detriment of other more useful protocols. It has even been suggested that the title of this book was dictated by purely commercial considerations and "UDP/IP Lean: Data Transfers for Real Applications" or some such title, although unlikely to make the best-seller lists, would have been a much more worthwhile project

In a belated but enthusiastic attempt to address this imbalance, the next three chapters expand your microcontroller horizons to include UDP for simple data transfer, DCHP for auto-configuration, and TCP clients and email protocols.

The terms client and server are used a lot in the coming chapters, so it is necessary to clarify what is implied by the use of these labels. While on the subject, it is worth looking at an alternative scheme: peer-to-peer networking.

Client Server Networking

Way back in Chapter 2, I suggested a client is the requester of a service, and the server is the provider of that service. These definitions can now be expanded.

• The client initiates contact with the server; the server responds to those contacts.

• There is generally a one-to-many relationship between a server and its clients.

• A server normally needs greater resources than a client.

• The labels client and server apply to logical functions within a node.

• A node can simultaneously host one or more clients and one or more servers.

The last...