5-4 CHAPTER 5: ROUTING WITH IPX
How IPX Routing Works
A router operates at the network layer of the OSI Reference Model. This
means that it receives its instructions to route packets from one segment to
another from a network layer protocol. IPX, with the help of RIP and SAP,
performs these network layer tasks. These tasks include addressing, routing,
and switching information packets to move single packets from one
location to another. This section describes the information included in an
IPX packet that helps it get delivered and the IPX packet delivery process.
IPX Packet Format The IPX packet format consists of two parts: a 30-byte header and a data
portion. The network, node, and socket address for both the destination and
source are held within the packet’s IPX header.
Figure 5-2 shows the IPX packet format.
Figure 5-2 IPX Packet Format
Checksum
Packet Length
Transport Control
Destination Network
Destination Node
Destination Socket
Source Network
Source Node
Source Socket
Upper-layer Data
Packet Type
(2 Bytes)
(2 Bytes)
(1 Byte)
(2 Bytes)
(2 Bytes)
(6 Bytes)
(4 Bytes)
(4 Bytes)
(6 Bytes)
(1 Byte)