Connecting to a Novell Network
481
SAP - Service Advertising Protocol
Operation: 4 NetWare Nearest Service Response
Service Advertising Set #1
Service Type: 4 File Server
Service Name:
ECORP......................................
Network Number: 0x34b62f24
Node Number: 00:00:00:00:00:01
Socket Number: 0x0451
Hops to Server: 1
Extra bytes (Padding):
. 00
Frame Check Sequence: 0x00000000
The return packet from Ecorp is a unicast back to the requesting client.
This is more efficient than a broadcast-based return, and the packet includes
information about the services provided and the internal network number.
At this point in the connection, the client has no knowledge of the services
available--the SAP table that contains the information about all servers was
not sent to the client. Rather, the client has a single server from which to
obtain this information. The GNS process presumes that the first server to
respond to the GNS request is the closest (or least busy) of equally preferable
servers.
Following the GNS response, the client requests routing information from
the router. Once this information is provided, the client establishes a direct
connection to the server.
Figure 9.1 provides a visual representation of the GNS process in an IPX
network where the server is separated from the client by a router. The first
two transmissions from the client are broadcasts, whereas the responses are
unicasts. NCP (NetWare Control Protocol) is a connection-oriented proto-
col that is used for primary Novell functions. Once the client and server
establish an NCP session, the client proceeds to the login phase.
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