Interchange node

An interchange node resides on the border of an APPN network and a subarea network. It provides protocol conversion between subarea and APPN networks to enable the integration of the two types of networks. Because an interchange node can convert session requests from one protocol to the other and can provide intermediate routing, it can establish sessions from one type of network to the other.

An interchange node combines the function of a subarea node and a network node. It controls resources and functions as a network node in the APPN network and as an SSCP and a cross-domain resource manager (CDRM) in the subarea network. All of the characteristics described for network nodes and subarea nodes apply to interchange nodes.

An interchange node:

Uses subarea path definitions to determine routes within the subarea network
Uses the topology database to determine routes within APPN networks
Uses both SSCP-SSCP and CP-CP sessions to communicate with other nodes
Has a subarea number and NODETYPE=NN defined
Can own and activate NCPs

The interchange node communicates network control data by using SSCP-SSCP sessions with other subarea nodes and CP-CP sessions with other APPN nodes. To enable it to participate in the subarea network, it is defined with a unique subarea number and requires subarea path definition statements. It can be connected to other APPN nodes, LEN nodes, and subarea nodes.

Note: The SACONNS start option must be set correctly to allow VTAM® to function as an interchange node.