The Issue
*CLI> pri set debug on span 1
1 TEI=0 MDL-ERROR (G): T200 expired N200 times sending SABME in state
5(Awaiting establishment)
1 Changing from state 5(Awaiting establishment) to 4(TEI assigned)
1 TEI=0 DL event: Q931_DL_EVENT_DL_RELEASE_IND(3)
1 TEI=0 Sending SABME
1 Changing from state 4(TEI assigned) to 5(Awaiting establishment)
Span: 1 Processing event: PRI_EVENT_DCHAN_DOWN
1 TEI=0 Sending SABME
1 TEI=0 Sending SABME
1 TEI=0 Sending SABME
1 TEI=0 MDL-ERROR (G): T200 expired N200 times sending SABME in state
5(Awaiting establishment)
1 Changing from state 5(Awaiting establishment) to 4(TEI assigned)
1 TEI=0 DL event: Q931_DL_EVENT_DL_RELEASE_IND(3)
1 TEI=0 Sending SABME
1 Changing from state 4(TEI assigned) to 5(Awaiting establishment)
Span: 1 Processing event: PRI_EVENT_DCHAN_DOWN
1 TEI=0 Sending SABME
1 TEI=0 Sending SABME
1 TEI=0 Sending SABME
1 TEI=0 MDL-ERROR (G): T200 expired N200 times sending SABME in state
5(Awaiting establishment)
1 Changing from state 5(Awaiting establishment) to 4(TEI assigned)
1 TEI=0 DL event: Q931_DL_EVENT_DL_RELEASE_IND(3)
1 TEI=0 Sending SABME
1 Changing from state 4(TEI assigned) to 5(Awaiting establishment)
Span: 1 Processing event: PRI_EVENT_DCHAN_DOWN
1 TEI=0 Sending SABME
1 TEI=0 Sending SABME
1 TEI=0 Sending SABME
1 TEI=0 MDL-ERROR (G): T200 expired N200 times sending SABME in state
5(Awaiting establishment)
1 Changing from state 5(Awaiting establishment) to 4(TEI assigned)
1 TEI=0 DL event: Q931_DL_EVENT_DL_RELEASE_IND(3)
1 TEI=0 Sending SABME
1 Changing from state 4(TEI assigned) to 5(Awaiting establishment)
Span: 1 Processing event: PRI_EVENT_DCHAN_DOWN
1 TEI=0 Sending SABME
1 TEI=0 Sending SABME
1 TEI=0 Sending SABME
1 TEI=0 MDL-ERROR (G): T200 expired N200 times sending SABME in state
5(Awaiting establishment)
1 Changing from state 5(Awaiting establishment) to 4(TEI assigned)
1 TEI=0 DL event: Q931_DL_EVENT_DL_RELEASE_IND(3)
1 TEI=0 Sending SABME
1 Changing from state 4(TEI assigned) to 5(Awaiting establishment)
Span: 1 Processing event: PRI_EVENT_DCHAN_DOWN
1 TEI=0 Sending SABME
1 TEI=0 Sending SABME It sounds like you may be experiencing an issue with your Link Access Procedure, Balanced (LAPB) protocol, which is used in X.25 networking to provide reliable data transfer.
The T200 timer is a retransmission timer used in LAPB to ensure that data frames are acknowledged within a certain time period. If the T200 timer expires before an acknowledgement is received, the sender will retransmit the data frame. If the T200 timer continues to expire multiple times without receiving an acknowledgement, it may indicate a problem with the connection or the LAPB protocol.
The N200 parameter is the maximum number of retransmissions that are allowed before the connection is considered failed. If the N200 limit is reached, the sender will send a SABME (Set Asynchronous Balanced Mode Extended) frame to reset the connection.
Possible causes of the T200 timer expiring and the N200 limit being reached could include:
- Network congestion or other issues causing delays in data transmission.
- Incorrect configuration of the LAPB protocol parameters.
- Hardware or software problems with the devices or communication channels being used.
To troubleshoot this issue, you may want to try the following steps:
- Check the network connection and ensure that there are no issues with the devices or communication channels being used.
- Check the LAPB configuration and verify that the T200 timer and N200 parameters are set correctly.
- Monitor the T200 timer and N200 values to see if they are consistently reaching the maximum limit.
- Try using a different communication channel or device to see if the issue persists.
- Check for any hardware or software problems with the devices being used.
If the issue persists after trying these steps, you may want to consider seeking additional help or consulting with a network administrator or specialist to further diagnose and resolve the problem.
