Categories: Internet/Intranets

Continued from HOW IRC WORKS

IRC is impressive enough on a standalone server, but its magic lies in the fact that IRC servers can be linked together into IRC networks, with each public channel accessible to any user connected to any server on that network. In other words, if you create a channel called #OFFICE97 to carry on discussions about using the software suite, any client on the server network can see the channel by using the /LIST command and can participate through the /JOIN command. All servers simultaneously keep track of which users are on the network, which channels are available, and which client is connected to which server. Two connected servers can make up an IRC network, but the large IRC networks--EFNet, DALNet, and the Undernet--connect as many as 100 servers at once, with user populations numbering in the thousands.

Several lists of networks are available on the Web, among which is Saint's List at home.sprynet.com/sprynet/saint. Smaller networks abound: AnotherNet offers a kids-friendly chat environment; StarLink IRC and IceNet stay clear of pornography and other offensive topics, as does the up-and-coming SuperChat. Kidlink and LinuxNet make their subject matter clear (and they work to keep it that way), and there's even ScoutLink for anyone in the scouting movement. Chat networks specific to particular geographic regions are becoming increasingly popular as well, as evidenced by the growth of Australia's OzOrg.

Since IRC servers are connected in a linear fashion (see Figure 2), they behave differently than the Internet itself. Unlike a Web transaction, in which data packets are rerouted whenever one node becomes unavailable, IRC networks experience frequent broken connections between servers, usually when network traffic becomes heavy. When the connection between two servers is lost, the network splits in what is called, unsurprisingly, a netsplit. In a 10-server network, for example, if server 7 loses its connection with server 8, the result will be a 7-server network and a 3-server network, and these can split even further. The servers will continually attempt to reconnect, however, and once they succeed, users will once again be able to chat.

If you're in a busy channel, you can tell if a split has occurred: Suddenly you'll see a message saying a large number of people have left the channel. They could have all opted out simultaneously, but the more likely explanation is a netsplit. If you want to keep chatting with these people, the best thing to do is to wait until the servers reconnect, for one very good reason. If you disconnect from your current server and join the same channel from another server, when the IRC network reconnects you might experience a nick collision kill. Essentially, this means that your nickname is present on two different servers, and upon seeing this, the servers will, in IRC terms, kill it on both of them. If you're in the middle of an enthralling conversation, that can be more than a little annoying.

Published as Internet Tools in the 05/27/97 issue of PC Magazine.