Key Properties: Provider Configuration

Along with a SIM card, the Service Provider should furnish three pieces of data you need to enter in the “Provider” section of the JACE platform’s GPRS Modem Configuration view (or default view of its station’s GprsPlatformService). See Figure 6.

Figure 6. Provider Configuration section of GPRS Modem Configuration view

Be sure to get the APN User Name and Password from the service provider (Wyless, for example). This is required for the GPRS modem to make the PPP connection.

Provider APN — The APN (Access Point Name) for the cellular provider network. This specifies the gateway between the mobile network and the Internet.
APN User Name — User name to authenticate to the provider’s network.
APN Password — Password for the above user, to authenticate to the provider’s network.

Above these APN-related properties are four checkboxes that apply to the PPP (Point-to-Point Protocol) stack used by the GPRS modem, described as follows:

Allow PPP Connections — Typically you leave this set (checked), unless you only need to have SMS messaging available, and don’t care about PPP.
Do not clear (uncheck) this unless you have some other local (alternate) connectivity to the JACE, otherwise, you will be unable to regain access.
Enable On-Demand PPP — Typically, you leave this cleared (disabled) for “always connected” PPP. Generally, this is enabled only if you are “pushing” all data from the JACE, such as when you care only about sending alarms/alerts. This results in less bytes sent (and billed), rather than maintaining a constant PPP connection. However, if data must be available for subscriptions—say, browser access to Px views, or there is proxied data in other stations, this checkbox must be cleared (disabled).
If only occasional access to data/Px views is needed, you could configure for on-demand PPP. In this case, when needed you could send the JACE’s GPRS modem explicit SMS messages to start up PPP and send back its IP address. This data could then be used to connect to it via the VPN network. For related details, see Remote SMS commands.
Enable PPP Debug — Typically, you clear (disable) unless you are diagnosing PPP authentication or parameter issues.
Switch Gateway on PPP Connection — Typically, you leave this enabled (checked), unless the Supervisor is on the same local LAN as the JACE.

Finally, review settings of the following five properties:

PPP Authentication Type — Either CHAP or PAP for Wyless (Service Provider dependent).
Min Time Before PPP Reconnect — This value guarantees that the pppd (PPP daemon) cannot respawn for this amount of time, providing a minimum down time, with a default value of 3 minutes. Typically left at default. Recommended not to be set under a minute, to allow for GPRS de-registrations, etc. to take effect. Typically of interest only when transmitted byte counts are of primary importance.
Max PPP Idle Time Before Disconnect — A value passed to the pppd when spawned, with a default value of 30 minutes. Typically left at default, after this amount of time with no data in the “PPP pipe,” the PPP connection is broken down, so it does not have to be maintained. This counter resets whenever PPP traffic occurs.
Max PPP Active Time Before Disconnect — (Available in AX-3.6, also builds 3.5.30 or 3.4.61 or higher) If set to 0 minutes (default if upgraded from previous 3.5 or 3.6 build), this timer is disabled. If a new modem under AX-3.6, the default is 1 day (24h 00m). This setting is available for the use case where the “Max PPP Idle Time Before Disconnect” has been set to 0 (disabling idle timeout), or if it has been set to some number; however, the occasional data sent by the station expects no response.

In either of the above scenarios, if an abrupt service outage from the network provide occurs, it is possible that pppd or the GPRS modem may never be notified that the PPP “pipe” it is using is no longer valid. The result is the JACE becomes unreachable from the remote end.

By specifying a time in this property, a shutdown and restart of PPP occurs even if the link is not idle, or if the idle time is disabled. Typically you should set this to a time much larger than the “Max PPP Idle Time Before Disconnect”, but one that would allow guaranteed “refreshing” of the link.
Max Number of Times LCP Can Fail Before Modem Reset — Default value is 10, range is from 2 to 100. Typically left at default, unless otherwise directed by Systems Engineering.

For additional details on these platform Provider Configuration properties, see the section Provider Configuration.