HP UX SNAplus2 manual 54

SNA Terms and Concepts

Basic APPN Concepts

network backbone topology—the nodes and transmission groups that can be used for routing sessions between any pair of nodes in the network.

In addition, the topology database on each network node contains local information about transmission groups from that network node to adjacent end nodes or LEN nodes.

The network node uses the topology database to calculate routes for sessions between LUs in its domain and remote LUs, or to provide information to other network nodes to enable them to calculate session routes.

•Each end node has a local topology database with information about transmission groups from that end node to adjacent nodes.

The end node provides this information to its network node server as part of the request to locate an LU and calculate a session route to that LU. The network node server uses the end node topology information when calculating the session route for the end node. The end node uses this information when establishing sessions with predefined LUs on adjacent nodes. The end node topology database supports communication only with adjacent nodes.

NOTE	APPN network nodes and end nodes also maintain topology information
	about links to a connection network (see “APPN Connection Networks”).
	LEN nodes maintain local topology information. They do not forward this
	information to a network node server.
	As shown in Figure 1-8, “Network Topology Database in Network
	Nodes,” network topology information is replicated at all network nodes,
	and local topology information is stored at network nodes and end nodes.

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