Additional Troubleshooting Procedure Here are some additional steps for troubleshooting:
- If you observe that the router is sending ISDN Q.921 IDREQs and is receiving no response from the ISDN switch, check that the SPIDs are configured correctly, verify the SPIDs with the telco, and if necessary, have the telco track the SPIDs. An example is shown below: 19:27:31: TX -> IDREQ RI = 19354 AI = 127 dsl = 0 19:27:33: TX -> IDREQ RI = 1339 AI = 127 dsl = 0 19:27:35: TX -> IDREQ RI = 22764 AI = 127 dsl = 0 19:27:37: TX -> IDREQ RI = 59309 AI = 127 dsl = 0 Observe that each IDREQ has an AI = 127 requesting that the ISDN switch can assign any TEI value available.
- Normally, the router is assigned the TEI by the ISDN switch during powerup. However, sometimes (notably in Europe) switches may deactivate Layers 1 or 2 when there are no active calls. In such situations, it is necessary to configure isdn tei-negotiation first-call under the BRI interface, so that TEI negotiation can occur when the first ISDN call is placed or received. Typically, this setting is used for ISDN service offerings in Europe and connections to dms100 switches that are designed to initiate TEI negotiation. maui-soho-01(config)#interface bri 0 maui-soho-01(config-if)#isdn tei-negotiation first-call In this case, you may have to initiate a dialout or receive a call for the TEI negotiation to occur. For dialout, ensure that your DDR configuration is correct.
- Reload the router.
- If you have performed all the above procedures and continue to have Layer 1 and 2 not properly established, contact the telco for further troubleshooting assistance