NCPROUTE operation

An NCP's IPOWNER statement defines the controlling host and the interface this NCP client must use to reach the host. The NCP client initiates contact with NCPROUTE by sending a datagram, known as a “Hello” message, to the controlling host. It transmits this datagram on UDP port 580.

Note: The port number is generated in the NCP (using the UDPPORT keyword on the IPOWNER statement) and configured in NCPROUTE.

The “Hello” message identifies the client NCP and determines which member from the hlq.NCPROUTE.GATEWAYS partitioned data set to use for this NCP's route table. Any valid MVS™ data set name can be used for the gateways data set.

The NCP client then sends a list of its inactive links to NCPROUTE. NCPROUTE uses additional routes defined for this NCP in the NCPROUTE gateways data set, as defined in the NCPROUTE profile. It also uses the inactive links provided dynamically by the NCP to build the current route table for this NCP. The following process is repeated for each NCP that has been generated to act as a RIP router:

A RIP packet arrives at the NCP client from a foreign router.
The NCP client sends this datagram to the NCPROUTE server.
The NCPROUTE server processes the RIP packet.
The NCPROUTE server creates a RIP update for an NCP client.
This update is sent to the NCP client.
The NCP client transmits the datagram to the network.

NCPROUTE sends route table updates to each NCP client every 30 seconds. After a client has been activated, updates must be supplied over each of its interfaces every 30 seconds. The NCPROUTE server creates these updates and sends them to the NCP client along with the IP addresses of other RIP routers that the NCP client should send them to.

At the same time, adjacent RIP routers are providing periodic updates every 30 seconds to NCPROUTE. These updates are sent by the NCP client to the NCPROUTE server, where they are processed, and the results are reflected in future updates back to the NCP client.

The NCP client sends all SNMP and RIP datagrams to the NCPROUTE server for processing. The NCPROUTE server provides RIP packets and SNMP replies to the NCP client to send to their final destination.