User manual

RLXIC-EV ♦ Intelligent Cellular Configuring your RLXIC-EV
RadioLinx® Intelligent Cellular Ethernet Gateway for Verizon User Manual
Page 84 of 104 ProSoft Technology, Inc.
March 10, 2010
Redundant Server
When a redundant server is enabled, each time a message is sent out to the
main, or failover, a second identical message will be sent to the redundant
server. This can allow the data to be used by two or more different applications.
The redundant servers can be running the same or different application than the
primary and failover servers. The messages to the redundant server are
independent of the primary/failover server settings or state.
You can set one or both redundant servers. The messages are sent
independently to either or both.
Note: Messages will be sent regardless if the server is available or not and do not use any reliable
mode format. Receipt of a message is not acknowledged nor is any message resent. Currently,
redundant servers cannot use TCP.
Store and Forward
Store and Forward will store reports when the primary Reports Server is
unavailable and forwards them when the server is available again. Store and
Forward can also group multiple reports in to a single message, rather than
individually.
The Report Server could be unavailable because the RLXIC-EV leaves
coverage, has very low signal (an RSSI of -105 or lower), or the server is
unreachable, regardless will store reports in memory. When the RLXIC-EV is
able to reach the server again, it will forward the reports.
The RLXIC-EV can also store messages and send them to the server in a packet
or only when the messages are requested rather than individually to conserve
bandwidth.
Reliability Modes
Reliability Modes provide methods for the RLXIC-EV and receive an
acknowledgment from the Reports Server to determine if a sent message was
received.
 Reliable Mode - The RLXIC-EV will transmit a sequence number (1 to 127)
as part of a packet of messages that may contain one or more reports. To
reduce overhead, the server only acknowledges receipt of every eighth
packet. The RLXIC-EV considers the eight packets a "window" of outstanding
packets.
If the RLXIC-EV does not receive acknowledgment for a "window", the device
will PING the server with a message containing the sequence numbers of the
first and last packets that have not been acknowledged. The RLXIC-EV will
continue until the server acknowledges receipt. When the RLXIC-EV receives
the acknowledgment, it will advance its "window" to the next group. When the
RLXIC-EV is first powered on (or reset), it will send a Set Window message
to synchronize with the server for the current "window".