Designing Large Scale Lans

Chapter 7. IPX

Internetwork Packet Exchange (IPX) is a Layer 3 protocol that forms the basis for Novell's network operating system (NOS) called NetWare. IPX was developed from the earlier Xerox Network System (XNS). Today, it is used almost exclusively to support networks of Novell NetWare servers. It is primarily used for file and printer sharing, but the capabilities are broader. IPX is able to carry a large variety of applications.

Unfortunately, some of the terminology adopted by Novell is different from that used in IP networks. For example, Novell calls every device that provides IPX services a router. This term can cause some confusion. Thus, in this book, I continue with the already adopted language. I call a device that provides application services a server. In this book, a router is a device that primarily performs Layer 3 network functions. As always, I strongly caution the reader against using general-purpose application servers to perform network functions such as bridging and routing.

Just running applications creates a lot of work for application servers. At peak utilization times, they frequently are unable to perform their network functions as well. Therefore, when the network is needed the most, it is unavailable for all applications, not just the ones served by this device. I mention this fact specifically in the context of IPX because Novell servers are frequently configured to either bridge or route—a situation I do not recommend.

Every device in an IPX network ...