Sap; Dns - Novell NETWARE 6-DOCUMENTATION Manual

SAP

DNS

24
Server Communications Administration Guide
The Service Advertising Protocol provides the same function in IPX networks
as SLP in IP networks. It registers information in a database and allows clients
to query the database to find services.NetWare servers using IPX use SAP to
advertise their services and network addresses. Routers gather this
information and share it with other routers. Workstations on the network
access the information provided by routers to determine which services are
available on the network and to obtain the IPX address of the services.
Workstations use this information to initiate a session with a service.SAP
makes the process of adding and removing services on an internetwork
dynamic. As servers start up, they use SAP to advertise their services; as they
are brought down, they use SAP to indicate that their services are no longer
available.As a router becomes aware of any change in the internetwork server
layout, this information is broadcast immediately to all neighboring routers.
SAP broadcast packets containing all server information known to the router
are sent periodically—the default is every 60 seconds. These broadcasts keep
all routers on the internetwork synchronized and provide a means of updating
routing information when a router or server has become inaccessible since the
last broadcast. A server might be inaccessible because a router went down, or
because a router dropped a packet containing a notification that the route to
the server is unreachable. Servers that are inaccessible do not appear in the
SAP broadcast.
The Domain Name System (DNS) is a distributed database system that
provides hostname-to-IP resource mapping (usually the IP address) and other
information for computers on an internetwork. Any computer on the Internet
can use a DNS server to locate any other computer on the Internet.
DNS is made up of two distinct components:
The DNS hierarchy specifies the structure, naming conventions, and
delegation of authority in the DNS service.
The DNS name service provides the actual name-to-address mapping
mechanism.