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Networking Concepts for the Accelar 1000 Series Routing Switch
be able to reach the network address in order to access the services. Applications
are statically stored on the server; when network users log on to the server and
request to use an application, the application is downloaded and executed within
the memory of the workstation.
Communication between a server and client require the use of numerous
protocols. As data makes its way through the protocol stack of one device on
the way to another device, the data is continuously enveloped by various protocol
headers until it is sent to the destination device. When the destination device is
reached, the headers that were added by the source device are sequentially
stripped away.
IPX Packets
An IPX packet consists of two major parts: a 30-byte header and the data portion.
The destination and source network, node, and socket addresses make up the IPX
packet header. The header contains fields with the following information:
•
Checksum
•
Packet length (Total length can range from 30 to 64,535 bytes.)
•
Transport control— indicating how many routers an IPX packet has passed
through on its way to the destination network (When the value reaches 16,
the packet is discarded.)
•
Packet type —a 1-byte field (Novell-specified) to indicate the type of service
such as RIP (1), SAP (4), NetBIOS (20), NCP (17), unknown (0)
•
Destination network, destination node, and destination socket
•
Source network, source node, and source socket
•
Data
Figure 7-2 shows the contents of the header, and Figure 7-3 shows the contents
of the four supported types of IPX packets.
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