Networks and servers are not the same thing. Servers are interconnected to make up a network. However, when you connect to a server of a network you are effectively connecting to that network. You cannot connect to a "network" directly, you have to connect to one of the networks servers
(Read it three times, maybe it'll become less confusing...maybe *G*). For example, Surrey.UK.EU.Undernet.Org is an Undernet server
but Undernet is the name of the network
You can connect to server pools also, which are IRC addresses that have several servers connected to them. For example, "irc.dal.net" would connect to any IRC server on DALnet (provided the server is open to normal users). Likewise, "uk.dal.net" would connect to any server based in the UK on the DALnet network.