DART 200 CDPD Modem User’s Guide | 5 DART Supported Protocols |
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.
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
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
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
