Sap Packet Structure - 3Com LANPLEX 2500 EXTENDEDPLEX®2500 EXTENDED User Manual

A workstation must first know a server's network address before it can
initiate a session with a file server.

SAP Packet Structure

SAP uses IPX and the medium-access protocols for its transport. The packet
structure allows the following functions:
A workstation request for the name and address of the nearest server of a
certain type
A router request for the names and addresses of all the servers or of all the
servers of a certain type on the internetwork
A response to a workstation or a router request
Periodic broadcasts by servers and routers
Changed server information broadcasts
Figure 6-5 provides an overview of the SAP packet structure. Note that the
packet structure is encapsulated within the data area of IPX.
IPX Packet Format
IPX Header (30 bytes)
Packet Type = 4
Socket = 452h
Data
Figure 6-5 SAP Packet Structure
SAP Packet Structure
Operation (2 bytes)
Server Entry (1) (64 bytes)
.
.
.
Server Entry (n) (64 bytes)
(n <= 7)
The Elements of IPX Routing
Server Entry Structure
Service Type
Server Name
Network Address
Node Address
Socket Address
Hops to Server
6-11
(2 bytes)
(48 bytes)
(4 bytes)
(6 bytes)
(2 bytes)
(2 bytes)