Sierra Wireless DART 200 CDPD Modem - Manual (Page 81)

DART 200 CDPD Modem User’s Guide 5 DART Supported Protocols
PN1197-00 Revision 1.0 5-27
SLIP initial testing
After the IP Addresses are set, the SLIP setup is completed, and the
modem has been put into SLIP mode, determine if your setup is correct
and that you have network connectivity by pinging the network.
The ping command format can vary slightly depending on the program
you are using. However, the following discussion provides basic
guidance regardless of the TCP/IP stack used. The general format of the
ping command is: PING nnn.nnn.nnn.nnn
The ping sends a fixed length of data (L) with an echo request to IP
Address nnn.nnn.nnn.nnn and waits for a time out period (T) for a
response. L and T can be quite different from one program to another, as
well as from the DART 200 ping values used with the AT*P command.
Consider the differences in these values between your program and the
DART 200’s AT*P when comparing results.
The DART 200 default ping values are L= 68 bytes, and T=10 seconds,
that result in ping times in the range of 600 to 1600 ms. Most SLIP
packages use a larger L and a smaller T than the DART 200, because
they were originally designed for land lines or Local Area Networks
(LANs) where ping times are much faster than with CDPD. Executing a
SLIP ping with its own default parameters over CDPD frequently causes
time-outs. If this occurs shorten the SLIP ping data length or increase the
timeout period to get successful pings.
To validate that you have set up the SLIP session between the DART
200 and the stack correctly:
1. Ping the modem. Make the modem’s SLIP address (1.1.1.2) the
target. If this ping operation is successful it demonstrates that your
setup is correct. This test can be done without being registered or
without CDPD being active.
2. Ping the DNS or a server at the local carrier. This Server IP Address,
like the DNS, is available from the carrier. If this ping operation is
successful, the SLIP system can communicate with the carrier.
If the ping fails and you are using a modem SLIP address other than
1.1.1.2 , you may have a routing problem. Refer to item 2 on p.5-25,
for guidance.
3. Ping an IP Address on the other side of the MDIS; usually, this is a
server, or a test terminal near you.
If this is successful, your SLIP system has network connectivity and
is now fully operational. If this ping attempt fails for reasons other
than time-out, suspect a bad IP Address, an unregistered IP Address,
or a router failure at the MDIS.
P P
TIP:
It's helpful when testing
to have two DARTs to
ping between. This
gives you control over
both ends of the link,
and can be done using
a single PC. Register
the first DART using
your PC, then switch
the PC to the second
DART, bring up SLIP,
and ping back to the
first modem. A
registered modem does
not need
an attached
PC to respond to a
ping
provided it is not
in SLIP mode.