Front End Service

Overview

The Front End Service is the inbound gateway that receives signals from field receivers and feeds them into SBN for processing. It listens on one or two TCP ports and accepts connections from the field; as signals arrive they are passed into SBN so they can be acted on right away. The service tracks each source so that duplicate or out-of-order messages are skipped and never processed twice.

A built-in timer continually checks that the configured ports are still listening and automatically restarts a listener if it has stopped, keeping the service available without manual intervention. The Front End requires a working SBN data-server connection and a valid SMTP server; if either is missing or invalid at start-up, the service logs the reason and stops. More than one Front End can run on the same machine, each with its own instance number and its own set of ports.

Service Manager

Instructions for installing and interacting with this service is found here.

Service Properties

Only properties specific to this service are listed here. Common service properties (SBN Server connection, Logging, SMTP) are found here.

Listening Port 1

The first TCP port the Front End listens on for inbound signal connections. Set this to a port the field receiver at <receiver-host> is configured to send to.

Listening Port 2

An optional second TCP port the Front End listens on. It must be a different value than Listening Port 1, and is disabled when set to 0.

Are Ports Listening?

A button that checks, on demand, whether the configured ports are currently active, so you can confirm the listeners are up and accepting connections.

Receive Timeout (in seconds)

How long the Front End waits for data on an established connection before treating the remote end as dead. When the timeout is reached the listener is reset and made ready for a new connection, which keeps a stalled or dropped connection from blocking the port.

Immediate Queue

Selects which immediate queue inbound signals are placed into. This is reserved for future use and must remain set to 1.

ZREC

The receiver (account) identifier the Front End reports itself to SBN as on start-up, so the system knows this Front End is online.

ZREC Timer (in seconds)

How often the Front End re-reports its ZREC status to SBN to indicate it is still running.