4.1 Client Locator To be able to exchange messages, two clients must be able to locate each other. Upon connecting to a server, a client registers using a label which is then used by other servers and clients to know where the client is located. Servers are responsible for keeping track of all the labels being used. The IRC protocol provides no mean for two clients to directly communicate. Management A channel is a named group of one or more users which will all receive messages addressed to that channel.
Channels provide a mean for a message to be sent to several clients.
Servers host channels, providing the necessary message multiplexing. Servers are also responsible for managing channels by keeping track of the channel members. This section is devoted to describing the actual concepts behind the organization of the IRC protocol and how different classes of messages are delivered. Thus the path of a message being delivered is the shortest path between any two points on the spanning tree. The following examples all refer to Figure 1 above.