When the gateway NCP receives contact from a network that has an unknown NETID, NCP accepts the NETID in the XID exchange. NCP uses an available pool network (which is a copy of the model network), assigns the unknown NETID to it, and marks it as dynamic, thus dynamically creating the network. As long as there are users of the dynamic network (the INN links are active), the network remains in existence. After there are no more active users of the network, the DYNAMIC network is cleared and returned to the pool, making it available for use by another network.

When a network is dynamically created within a gateway NCP, all gateway VTAMs that have activated the physical unit of that NCP are notified and made aware of the new network. Also, whenever a gateway VTAM® activates the physical unit of a gateway NCP, that VTAM is notified of all dynamic and static (predefined) networks. VTAM is also notified when dynamic networks are cleared and no longer exist.

Dynamic network capability is supported on leased, subarea dial, and NTRI INN links. The protocols used for dynamic NETID depend on whether the link is a leased (including NTRI) or switched line. For detailed information about the NETID negotiation protocols used for link activation between two NCPs, see the NCP, SSP, and EP Resource Definition Reference.