The following figure provides an overview of node-to-node forwarding processing.
Figure D-6 Overview of node-to-node forwarding processing
![[Figure]](figure/zu990900.gif)
![[Figure]](figure/zu991000.gif)
The flow of processing shown in the figure is described below. The numbers correspond to the circled numbers in the figure. Number 1 describes TP1-X processing, and numbers 2-10 describe TP1-A, TP1-B, and TP1-C processing.
- As a result of a name service search, TP1-X sends a service request to the schedule service of node TP1-A.
- This service request is not queued because the server of TP1-A was shut down when the schedule service of TP1-A attempted to issue the service request.
- The schedule service searches the name service for a forwarding destination.
If the RPC request of the program that issued the service request is using the scheduler direct facility with the dc_rpc_call_to function, the schedule service returns an error to that program without forwarding the request.
- The service request is forwarded to the schedule service of TP1-B.
- The service request is not queued because this server's load level is high (2).
- The schedule service searches the name service for another forwarding destination.
- The schedule service forwards the service request to the schedule service of TP1-C.
- The service request is registered in the message queue because this server is not shut down nor is its load level high.
- Executes the service function.
- After the service function has executed, the UAP (server UAP1) that received the service request sends a response message directly to the UAP that issued the service request.