Open System Services Management and Operations Guide (G06.25+, H06.03+)

Introducing Open System Services
Open System Services Management and Operations Guide—527191-002
1-17
Interprocess Communication Facilities
forth by the transport-agent processes. Transport-agent processes do not
communicate with each other directly, but through the transport-provider.
For example, given the situation pictured in Figure 1-6 on page 1-18, suppose
Process 2 sends a message to Process 4. The following occurs:
1. The message is forwarded by $ZTA01 (the transport-agent process on processor 1
of Node A, where Process 2 is running) to $ZTC0 (the transport-provider process
that supports the IP address used by Process 2).
2. The message is sent over the network and is received on Node B by $ZTC0 (the
transport-provider process that supports the IP address used by Process 4).
3. The message is forwarded to $ZTA01 (the transport-agent process on processor 1
of Node B, where Process 4 is running).
4. The message is delivered to Process 4 when that process is ready to accept the
message.
Note. Whenever any application process sends a message to another process, the message
is always sent through the transport-provider processes and through the network, regardless of
which processors or nodes they are running on. Even when two processes are running on the
same processor, a message from one to the other always goes to the transport-provider
process first.