SSCP and Cross Domain Manager

Every z/OS system with VTAM that implements SNA is referred to as a domain, which is an area of control. Within a subarea network, a domain is that portion of the network managed by the SSCP in a T5 subarea node.

A subarea network that contains only one T5 node is a single-domain subarea network. When there are multiple T5 nodes in the network, each T5 node may control a portion of the network resources. A subarea network that contains more than one T5 node is a multiple domain subarea network.

The SSCP can also set up and take down sessions with other domains through the cross-domain resource manager (CDRM). Before applications in one domain can have cross-domain sessions with resources in  another domain, a CDRM session must be established between the SSCPs of the two domains.

For a session between SSCPs to exist, VTAM must know about all cross-domain resource managers with which it can communicate. You must define to VTAM its own cross-domain resource manager and all other cross-domain resource managers in the network.

The cross-domain resource manager that represents the SSCP in your domain is called the host cross-domain resource manager. The cross-domain resource managers that represent the SSCPs in other domains are called external cross-domain resource managers.