Understanding the network.pdf - Back to Home

Figure 3.15. SAP message format.
• Operation is a 16-bit field that describes the packet's informational purpose.
o Request is a general informational request about all the servers on
the network.
o Response is a reply to a SAP request or a general SAP announcement
sent by servers and routers every 60 seconds (default).
• GetNearestServer is a specific request sent by a host to locate the nearest
server.
• GiveNearestServer is a response sent by a router or server with the SAP
information about the server closest to the requesting end-station.
• Service Type is a 16-bit field that indicates the kind of service being
provided.
• Server Name can be up to 384 bits in size. It describes the unique name of
the server. SAP provides the naming service used by NetWare. Each server
on the internetwork requires its own unique name. SAP is used exclusively
for name service in all versions of NetWare up to version 4.0. With NetWare
4.0, NetWare Directory Services (based on the ISO x.500 standard) is used
for name service. SAP, however, is still needed for server locating and
printing.
• Network Address is a 32-bit value.
• Node Address is a 48-bit value.
• Socket Address is a 16-bit value.