What the topology agent does

At the request of the topology manager, the VTAM® topology agent gathers information about the network and sends it to the topology manager. The topology agent can send the following information:

Information about the local topology
This includes information about:
- The local agent host
- Resources owned by the agent host
- Resources defined to NCPs owned by the agent host
- TGs, lines, and PUs supporting those connections
- Names of contacted APPN and subarea nodes, and partner link-station names when available
Information about the network topology
This includes information about the APPN network nodes and subarea CDRMs known to this VTAM and the TGs and VRs that connect them.
Information about LUs that includes:
- Cross-domain resources
- USERVARs
- Generic resources
- Application programs
- Local non-SNA terminals
- Owned LUs (those activated or defined to the VTAM, but not local to this VTAM)
Information about a particular resource, by name
Event notifications

The VTAM topology agent sends this information by way of CMIP snapshot actions, get requests, and event notifications. Snapshot actions send an initial view of certain groups of resources, depending on the type of snapshot. Ongoing snapshots keep reporting the status changes for the resources in respective groups, until the snapshots are stopped. Get requests gather information about a particular resource at a single point in time.

An event notification is a report that indicates when a resource changes, in contrast to snapshot actions, which give information about resource connectivity as well.