Meaning – The term peripheral host node, refers to a node that provides an application programming interface (API) for running application programs but does not provide SSCP functions and is not aware of the networkconfiguration. The peripheral host node does not provide subarea node services. It has a boundary function provided by its adjacent subarea.
Type 2.1 peripheral nodes can communicate with each other, and with application programs in VTAM. Communication between type 2.1 peripheral nodes can occur through the main communication path among the subarea nodes in the network. Type 2.1 peripheral nodes support link-level role negotiation, eliminate hierarchical control (no ACTPU or ACTLU unless PU requests), require fewer flows to establish sessions, and use dynamically assigned session identifiers rather than preassigned addresses, all of which require fewer system definitions.
Example of usage – “VTAM performs the directory services function for the subarea network and any APPN end nodes it serves. It locates the other session partner through a type 2.1 logical unit session request. VTAM is also involved in the session setup process when the type 2.1 session request traverses the subarea network, or when it is acting as a network node server for an APPN end node.”