Listen End and Connect End
In a pair connection, the assignment of listen end and connect end is not arbitrary. Instead, it depends on the type of interaction, or on the bus topology. To simplify transport configuration, follow these guidelines.
In general, a process that must start first is a good candidate for the listen end of pair connection. This rule helps avoid situations in which programs send messages before the transport establishes a pair connection bus.
| Situation | Listen End | Connect End |
|---|---|---|
| Request/Reply Interactions | Replying process | Requesting process |
| Server and Clients | Server | Clients |
| Long-Lived Process and Ephemeral Processes | Long-lived process | Ephemeral processes |
| Hub-and-Spoke Topology | Hub | Spokes |
Start Order
Administrators must arrange for processes to start in the correct order, according to application semantics. If a requesting process starts before the replying process, the replying process could miss the first request (or several requests).
The principles that determine which processes must start first are similar to the principles that determine the preference for listen end of a pair connection (see the preceding table). Namely, replying processes, servers, long-lived processes and hub processes must start first.