Supervising the Network

7-15
Maintaining the NetWare Server
About NetWare Networking Protocols
Routing Information Protocol (RIP)
The RIP allows routing information exchange on a NetWare internetwork.
The single packet structure defined by the RIP allows the following
exchanges of information:
• Workstations locate the fastest route to a network number by broadcasting a route
request.
• Routers request routing information from other routers to update their own
internal tables by broadcasting a route request.
• Routers respond to route requests from workstations and other routers.
• Routers perform periodic broadcasts to make sure that all other routers are aware
of the internetwork configuration.
• Routers perform broadcasts whenever they detect a change in the internetwork
configuration.
Service Advertising Protocol (SAP)
The SAP allows service-providing nodesæsuch as file servers, print servers,
gateway servers, and client workstationsæto advertise services and
addresses. The SAP makes adding and removing services on an
internetwork dynamic. As servers are booted, they advertise services to
other nodes through the SAP; when they are brought down, they use the
SAP to indicate that services are no longer available.
Through the SAP, clients on the network can determine what services are
available on the network, and obtain the internetwork address of the nodes
where they can access those services. This is an important function, since a
workstation cannot initiate a session with a file server without the server
address.
A gateway server, for instance, will broadcast a SAP packet periodically
(usually every 60 seconds, the period defined for all servers advertising with
the SAP) onto the network segment to which it is connected. The SAP agent
in each router on that segment copies the information contained in the SAP
packet into an internal table called the Server Information table. Because the
SAP agent in each router keeps up-to-date information on available servers,
a client wanting to locate the gateway server can access a nearby router for
the correct internetwork address.