2.10. OVER THE AIR [ADVANCED]
tination
takes place on any of the following situations:
•
For IP-type destinations (Tracking Servers):
1. The GPRS session is down.
2. When using TCP: The GPRS session is up but the TCP
connection with the IP-host is closed and cannot be estab-
lished or the host is unreachable.
3. When using UDP: The GPRS session is up but the IP-host
is not acknowledging UDP reports
•
For Telephone Numbers destinations:
1. The unit is not registered on the GSM network
2. There is no Telephone Number defined on the report’s
Des-
tination
.
•
The serial port destination is never buffered.
The unit has an event buffering capacity of
1137
events. Events are
buffered and transmitted on an individual manner for each
Destina-
tion
meaning that an unreachable destination may have many pend-
ing events while other destinations have their buffer empty with no
interference between the two destinations. The total buffer capacity
whatsoever is shared among all destinations meaning that the max-
imum holding capacity is always restricted to the free space left by
the destination with the maximum accumulated reports.
The buffering capacity may be significantly lowered by a miss-
configured or permanently-unreachable
Destination
.
Note:
The buffer is automatically controlled by the unit according to the
situations described above and whenever the conditions change for
good the unit starts emptying the buffer as messages are successfully
transmitted to destinations.
The state for the buffer for a given
Destination
can be consulted
with the
XASF
message.
2.10
Over The Air [Advanced]
Interacting with the unit remotely (Over the Air) is not different than
doing it locally. The unit’s configuration and operation is controlled
6
The UDP acknowledging mechanism is optional and can be turned off/on.
40