Auto-Negotiation

In the start when then networking first begin there was no mean for the adapters to negotiate the best possible shared mode of operation, therefore, the adapters were unable to achieve high speeds as compared to the adapters of today. The first negotiation protocol for the adapters was released in the 1995 so that the adapters could automatically negotiate with one another and can attain higher speed by sharing and working on the common parameters present in both the adapters.

The Auto-negotiation technology was introduced by the National Semi-conductor, to the IEEE 802.3u working group. The basic reason for this protocol is not simply to ensure that the adapters in the network are able to achieve higher speed, it performs another function too, that is, it is used to accommodate the multi-speed network devices that are present in the network. The mechanism on which the auto-negotiation protocol work is that when a connection is made with the other device on the end of the line, that is, destination device, it then detects the various modes that exist in that destination device, after that it advertises the source device ability to automatically configure the best or the highest performance mode of interoperation. In this way basically the auto-negotiation protocol helps about in bring the maximum speed that can be obtained between two network adapters, that is, the source and the destination.

This procedure can work for different components of the network like switch, Ethernet, routers, severs etc. The latest tweaks made to this technology have enabled the auto-negotiation procedure to do three things, attain maximum speed possible, duplex mode and to maintain the flow control between the two devices. The first use of this auto-negotiation can be traced back to the series of Fast Ethernet where this procedure was an optional component, however, today it is widely used in the networking world.