Data Channel Troubleshooting

Possible Setup Issues

• Before trying to establish a packet data connection, you must make sure that the following settings properly configured:
  • the Session Application Type must be set to the Default Packet Application.
  • Cell band and channel must be set to the proper values for your AT (see How Do I Change Call Parameters? ).
  • LAN IP Address 2 (Data+) must be set correctly if the test set supports the LAN 2 PORT . This address must be set on the same subnet as the LAN IP Address and must not be identical to the LAN IP Address.
  • Call Limit Mode must be set to off.
  • Cell Power must be set to an adequate level and AWGN Power must be set to an adequately low level to allow for successful data connection processing.
• If the test set's internal PDSN is used for packet data connection via simple IP protocol (see How Does Test Set Support Simple IP Packet Data Connection? ).
  • you must properly set a DUT IP Address for your AT and make sure the External PDSN State is set to Off (see Data Channel Parameters ).
  • see Packet Data Service Example Procedure (via Simple IP) for an example packet data connection procedure using Simple IP protocol.
• If the external MOB-IP-SIM is used to supply the PDSN simulation (providing Mobile IP protocol, see How Does Test Set Support Mobile IP Packet Data Connection? ).
  • you must properly specify the External PDSN IP Address and the External PDSN TCP Port , and make sure the External PDSN Connect Timeout is not set to zero. Then turn the External PDSN State to On . See Data Channel Parameters .
  • see Packet Data Service Example Procedure (via Mobile IP) for an example packet data connection procedure using Mobile IP protocol.

Other Considerations

• It is recommended not to execute a preset/reset (full or partial) when a session is open with an AT. This is because executing a preset/reset (full or partial) will take the test set to Idle state without signaling to the AT and may cause the test set and AT in a mismatched state. In this case, some ATs can not open a new session with the test set.
• You should always set the AT Directed Packets to 100% for maximum throughout. This allows the test set to send data to the AT under test in all possible slots. Note that achieving maximum throughout also depends on other parameters of your test setup such as Window Size, TCP or UDP protocol, etc.
• The packet data connection can only be started from your AT. You can not start a packet data connection using CALL:FUNCtion:DATA:STARt command. Otherwise, an error message will be generated due to without having a PPP connection established.
• If you are trying to end a packet data connection from the test set, use CALL:FUNCtion:DATA:DORMant command instead of the CALL:FUNCtion:DATA:STOP. Sending CALL:FUNCtion:DATA:DORMant command results in data connection status going to Dormant state. This indicates that the physical connection (traffic channel) is closed but PPP connection is maintained. See Dormant State .
• Use Ping function to verify the system interconnect.
  • See How Do I Ping a Device From the Test Set? .
  • When the external MOB-IP-SIM is providing PDSN service to the AT, the AT's IP address is assigned by the MOB-IP-SIM. The setting by DUT IP Address is ignored and the ping to DUT functionality is not functioning (see Ping the DUT from the test set ).
• Ping log has an unknown IP address: If you log a Ping that originated from the test set, the Ping forward link Source Address and the reverse link Destination Address have a fixed value of 130.29.181.203. This is because the test set uses an internal address to originate IP data from the test set to the AT. See Protocol Logging During Ping for more information.

Related Topics

Data Channel

Packet Data Service Example Procedure (via Simple IP)

Packet Data Service Example Procedure (via Mobile IP)