Chapter 3. Cluster 1600 networking 117
switch to the destination nodes. The amount of traffic coming in through the FDDI
network can be up to ten times the bandwidth that the SP Ethernet can handle.
For bigger demands on routing and bandwidth, the SP Switch router can be a
real benefit. For more information, refer to 2.4.1, “SP Switch Router” on page 34.
3.5 Using NIS in a Cluster 1600 configuration
Network Information System (formerly called the “yellow pages” or YP, and now
NIS). NIS provides a distributed database service for managing the important
administrative files, such as the passwd file and the hosts file. NIS’s main
purpose is to centralize administration of commonly replicated files, letting you
make a single change to the database rather than making changes on every
node within a network environment.
NIS separates a network into three components: domains, servers, and clients.
An NIS domain defines the boundary where file administration is carried out. In a
large network, it is possible to define several NIS domains to break the machines
up into smaller groups. This way, files meant to be shared among five machines,
for example, stay within a domain that includes the five machines and not all the
machines on the network.
An NIS server is a machine that provides the system files to be read by other
machines on the network. There are two types of servers: master and slave.
Both keep a copy of the files to be shared over the network. A master server is
the machine where a file may be updated. A slave server only maintains a copy
of the files to be served. A slave server has three purposes:
To balance the load if the master server is busy.
To back up the master server.
To enable NIS requests if there are different networks in the NIS domain. NIS
client requests are not handled through routers; such requests go to a local
slave server. It is the NIS updates between a master and a slave server that
go through a router.
An NIS client is a machine that has to access the files served by the NIS servers.
Since NIS is not directly related to a Cluster 1600 managed by PSSP
configuration we have created an appendix that covers the basic NIS terms.
Therefore, for more information about NIS and how to configure it, refer to
Appendix B, “NIS” on page 537.

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