SNA Terms and Concepts

Basic APPN Concepts

Figure 1-7

Network Node Directory

A network node locates a remote LU as follows:

1.The network node receives a request to locate an LU. The request can be any of the following:

•The name of a destination LU sent by an end node or a LEN node to its network node server

•An LU name specified in a LOCATE search request from an end node

•An LU name specified in a BIND request from a LEN node

•An LU name specified by a TP on the network node

2.If the destination LU is not located in the network node—but appears in its directory—the network node sends a directed search request to the destination network node server to verify the location of the LU.

If the LU is not in the network node directory, the node initiates a search of the network by sending a broadcast search to every adjacent network node.

3.Each node in turn propagates the broadcast and returns replies indicating success or failure.

For its future needs, a network node caches information obtained from successful broadcast searches.

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Chapter 1