Overview

With today's ever changing networks in terms of speed and functionality, and the fact that every desk has some measure of computing capability, it is now becoming a requirement that devices should be able to operate in a " plug and play" manner. Certainly, the accounts department has little need to know or understand the complexities of the network to which they connect. Their interest lies only in the speed and functionality that they have purchased and that they expect to be delivered. Hence, it is now becoming a prerequisite that devices should require little or no user interaction in terms of configuration.

For this reason, many vendors now incorporate the ability to auto-negotiate features such as whether the device will operate at 10Mbps or 100Mbps and whether Full Duplex operation is supported. Although not mandatory, auto-negotiation provides a standardized method through which DTEs can exchange configuration information with hubs or switches to which they are attached. Figure 11-1 shows an example of this where we have several stations, each with different capabilities but sharing the same switch. This chapter details the process of auto-negotiation, and chapter 12 then expands upon this to discuss other associated features such as Full Duplex operation and Flow Control.

Figure 11-1: Example of Where Auto-Negotiation Is Used

Two points however must be made. Firstly, auto-negotiation is defined only for point-to-point copper implementations (i.e., XBase-T). Secondly, auto-negotiation is not infallible. Certainly, vendors strive to ensure interoperability, but with the best...