IPX/SPX

IPX/SPX
When Novell NetWare was introduced, it was designed to be a server platform for a local area and wide area networks. To that end, Novell designed a protocol stack that was very efficient
over local area networks and that would also work on wide area networks. That protocol stack was the Internetwork Packet Exchange/Sequenced Packet Exchange (IPX/SPX).
In the following sections similar information to that presented for TCP/IP will be presented so that you may compare similar features, including addressing, routing, and naming, between
the two.

 Addressing
IPX is the Network layer protocol that handles addressing and routing for the IPX/SPX protocol stack. IPX addressing is actually very simple. It takes the 12-digit hexadecimal address because
that is the address for the individual node on that network segment. The network segment is referred to by its own unique 8-digit hexadecimal address. For example, the address
0001ABF3:12AB341FF414 would correspond to an interface with a MAC address of 12-AB- 34-1F-F4-14 on the network segment labeled 0001ABF3. Every network segment is assigned its own, unique IPX network address. Since the MAC address is burned in to the NIC at the factory and, for the most part, shouldn’t be changed, it doesn’t have to be configured. The only configuration
that must be done is to assign the IPX network address and configure the server with that address.

Note:

In addition to a station address, routers are given an internal IPX address. This address uniquely identifies a router to the rest of a network. NetWare servers always have an internal IPX address because they can function as routers.

Routing
Most routers that route TCP/IP traffic can also route IPX traffic (although they may require additional software or configuration). IPX/SPX is a routable protocol stack because its address
strucure is hierarchical, with a network portion and a node portion. As a result and to increase functionality, IPX/SPX has routing protocols designed into it. The routing protocols for IPX/SPX are RIP and NLSP. IPX RIP is very similar to the RIP protocol in TCP/IP in that it is the distance vector routing protocol for IPX. Similarly, NLSP is the link state routing protocol for IPX/SPX. Both work similarly to their TCP/IP counterparts. RIP uses broadcasts of the entire IPX routing tables to keep all IPX routers updated, although every 60 seconds, not 30 as with IP RIP, and just as OSPF
does, NLSP sends out only the changes to the routing tables and then only to a select group of network addresses. NLSP is actually based on another link state routing protocol, ISO’s Intermediate
Sytem to Intermediate System (IS-IS).

Interoperability
IPX/SPX isn’t as ubiquitous as TCP/IP (which can even be found running on Coke machines), but it holds its own when it comes to allowing many different platforms to talk. Windows 9x,
NT, Me, 2000, XP, and2003 as well as NetWare, and a few versions of Linux come “out of the box” with support for communicating with other entities via the IPX/SPX protocol stack,
although Microsoft calls its completely compatible version NWLink. Before the popularity explosion of the Internet in the mid-1990s, the IPX/SPX protocol stack was the only protocol
stack many companies would run.
     The only downside to interoperability using IPX/SPX is that many versions of Unix and other high-end operating systems like OS/400 don’t come with built-in support for the IPX/SPX protocol stack or even with an option for support.


Naming
Really, the only devices that have names are the NetWare servers. Generally speaking, you can name a NetWare server anything you want, as long as you follow these rules:

• The name must not include any of the “illegal” characters, including a period (.), a comma (,), a plus sign (+), an equal sign (=), and a backslash (\).
• Names must have fewer than 64 characters.
• Names are not case sensitive.

These names are resolved using either Bindery Services or Novell Directory Services.

Note:

These will be discussed more in Chapter 5, “Major Network Operating Systems.”