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Introduction to Novell IPX
419
IPX Addressing
After sweating through IP addressing, IPX addressing should seem like a day
at the beach. The IPX addressing scheme has several features that make it a
lot easier to understand and administer than the TCP/IP scheme.
IPX addresses use 80 bits, or 10 bytes, of data. As with TCP/IP addresses,
they are hierarchical and divided into a network and node portion. The
first four bytes always represent the network address, and the last six bytes
always represent the node address. There's none of that Class A, Class B,
or Class C TCP/IP stuff in IPX addressing--the network and node portions
of the address are always the same lengths. After subnet masking, this is
sweet indeed!
Just as with IP network addresses, the network portion of the address
is assigned by administrators and must be unique on the entire IPX inter-
network. Node addresses are automatically assigned to every node. In
most cases, the MAC address of the machine is used as the node portion
of the address. This offers several notable advantages over TCP/IP address-
ing. Since client addressing is dynamic (automatic), you don't have to run
DHCP or manually configure each individual workstation with an IPX
address. Also, since the hardware address (layer 2) is included as part of
the software address (layer 3), there's no need for a TCP/IP ARP equiva-
lent in IPX.
As with TCP/IP addresses, IPX addresses can be written in several
formats. Most often, though, they're written in hex, such as
0000.7C80.0000.8609.33E9.
The first eight hex digits (0000.7C80) represent the network portion of
the address. It's a common IPX custom when referring to the IPX network
to drop leading zeros. Thus, the above network address would be referred to
as IPX network 7C80.
The remaining 12 hex digits (0000.8609.33E9) represent the node por-
tion and are commonly divided into three sections of four hex digits divided
by periods. They are the MAC address of the workstation.
You must understand IPX addressing and be able to differentiate between the
network number and node number when looking at an IPX address.
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