Previous versions of NetWare used Internetwork Packet Exchange (IPX), a proprietary protocol developed by Novell®, for network communications. NetWare 6 uses TCP/IP (Transmission Control Protocol/Internet Protocol), IPX, or a combination of both IP and IPX.
With increasing access to worldwide data exchange through the Internet, IP has become so popular that many companies'networks now require it. But IPX and IP are two separate protocols. If you run both, you must maintain both. Administering routers, bridges, switches and other hardware components required for multiprotocol network communications can prove prohibitive.
Potentially, migrating from IPX to IP could prove costly, and there are some important considerations. Attempting to move a large number of servers and clients to NetWare 6 simultaneously won't generally be practical. It may be neccessary to introduce IP components over time, depending on the size and complexity of your network. You might choose to upgrade only servers as a preliminary phase, and later upgrade clients. To understand your migration options, see Planning Migration.
Although Novell now recommends the use of pure IP on your network, small, private networks might be more efficient using an IPX-only implementation. As you'll see in the discussion regarding addressing, IPX requires no special address resolution protocols---it can assign addresses dynamically, and addresses are abundant. IP is better suited for large IP-based networks attached to the Internet, to WAN links, or where IP is the exclusively required protocol. If you don't require IP for any of these reasons, and you can use a pure IPX network, you might find IPX implementation easier to administer.