Client controllers
The following table lists the basic hardware requirements for client controllers.
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Client controllers
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Minimum RAM 4 MB
Recommended RAM 8 MB
Minimum hard disk 80 MB
LAN Ethernet
WAN optional
Floppy disk installation only
Tape optional
Client controllers are located between clients and the server,
and have the task of regulating traffic over the network. They
can do this by acting as a gateway between sub-networks
connecting locally grouped client machines. They are also
used as boot servers for diskless clients.
Client controllers have almost exactly the same hardware configuration as disk based clients, the only exception being a possible second network card. The first network card enables the client controller to communicate with the server and the second, when present, enables the controller to communicate with the clients. While any physical network can be used to link the client controller to the server, Ethernet is generally used to communicate with any diskless clients that require boot image downloading.
Client controllers with two or more network adapters are generally used as download servers for multiple diskless clients (as described above) and/or as gateways to other networks. For example, a client controller may be responsible for taking care of downloading diskless clients and communicating with a server system connected via a WAN.
Client controllers with a single network card are generally used to gather and concentrate information from multiple clients and then pass that compressed information on to the server. The collection and compression of this information is an application function that must be implemented by the application programmer.
Figure B-1 Client controllers with one network card
Using client controllers with a single network card to download boot images to diskless clients is possible. However, if there are a lot of diskless clients connected to the same controller, the network may become flooded with the data being downloaded. A more suitable configuration for downloading multiple diskless clients is to connect them to client controllers with two network adapters.