Assume that a Novell client intends to make a connection to a Novell server that offers a particular service such as file services (type 4). The client sends a GNS (get nearest server) broadcast request out of its LAN interface card. If a Novell server offering this particular type of service (file service = type 4) is present on the local LAN, it will reply to the client's request and the local router(s) remain silent. Otherwise, the router searches in its IPX servers table (sometimes referred to as SAP [Service Advertisement Protocol] table) to see if an entry that matches the client's request is present.
Routers build and maintain IPX server tables by accepting SAP broadcasts that are generated by other neighbor devices. If more than one entry is present, the closest one (hop count) is furnished, and in case of a tie, the most recent entry is chosen. A reply is not sent if there is a GNS-reply filter configured on the corresponding interface of the router. The router's reply contains the selected server's internal IPX address. When the client receives the router's reply (containing a remote IPX address), it will generate a RIP (broadcast) request for the received (server's internal) network address. Once again, the router has to do a search, this time in its IPX route table to see if there is an entry that matches the client's request. If the router finds a match, it sends a RIP reply to the client. Finally, the client sends an NCP (Novell Core Protocol) request to the remote Novell server to establish a connection (log in). Once a connection is built between the Novell client and server, the file sharing mechanism begins.
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