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Understanding
13
Internetwork Packet Exchange
103-000176-001
August 29, 2001
Novell Confidential
Manual 99a
38
July 17, 2001
For more information about the IPX protocol, refer to
Š “IPX Packet Structure” on page 13
Š “IPX Addressing” on page 17
Š “How IPX Routing Works” on page 21
IPX Packet Structure
The IPX packet is similar to an XNS IDP packet and comprises two parts:
Š A 30-byte IPX header , which includes the network, node, and socket
addresses for both the destination and the source
Š A data section, which often includes the header of a higher-level
protocol, such as SPX
The minimum IPX packet size—excluding the MAC header—is 30 bytes
(IPX header only). Historically, the maximum size of routed IPX packets has
been 576 bytes (IPX header and data). Until recently, all routed IPX packets
were between 30 and 576 bytes. However, the IPX protocol has always
allowed packet sizes up to 65,535 bytes.
NOTE:
Media constraints typically limit the actual maximum packet size allowed to
something less than 65,535 bytes. Ethernet II packets, for example, are limited to
a data size of 1,500 bytes, not including the MAC header.
The IPX header is placed after the MAC header and before the data. Figure 2
on page 14 shows the structure of an IPX packet.