What is relation of show isdn status with show ip interface bri when checking isdn status

[eigrpy]

Hi I am confused with some questions in voip. I hope you can help to understand it. Here are two commands to check isdn status:

First one is show isdn status, and second one is show ip interface bri

When I setup isdn between two routers, the output of the second command are almost always showing "up" for isdn(interface s0/0/0:23), but the output of the first one sometimes show " State = MULTIPLE_FRAME_ESTABLISHED", which we call normal, while a lot times show "State = TEI_ASSIGNED", which we call abnormal

I am wondering what can cause the situation where the first command show abnormal and the second show normal. What does that mean with the situation? Thank you

We search the regular protocols for configuring isdn, and we got a lot. I guess this is because of different protocol for different type of routers. but main config commands are same. This might be reason we did not use proper commands and got the abnormal.  

[Carlo Poggiarelli · Accepted solution]

Hi,

When the controller shows UP but the layer 2 status in a show isdn status output is TEI-ASSIGNED, it means that cable is in both controller interface and TELCO device but there is no frame exchange between your vg and teclco because of an incorrect controller configuration or a telco remote issue.

Also an incorrect or damaged cable could be the cause.

MULTIPLE FRAME ESTABLISHED mean that all is working correctly and you should be able to make and receive calls 

HTH

Regards

Carlo

[eigrpy]

Thank you all!

[Venkatesh Perumal · Accepted solution]

do you experience any call failure as these states are often temporary, refer the below troubleshooting link for reference.

The most often seen Layer 2 states are MULTIPLE_FRAME_ESTABLISHED and TEI_ASSIGNED. A state=MULTIPLE_FRAME_ESTABLISHED indicates there is data link connectivity to the Telco ISDN switch. This is the state that you should see under normal operations. Any other state usually indicates a problem on the circuit. A state=TEI_ASSIGNED indicates that the router has lost connectivity to the switch. This is normal if the Telco (commonly in Europe) deactivates Layers 1 and 2 when there are no active calls. If this is not the case, proceed to Troubleshooting BRI Layer 2 for more information on Layer 2 issues. Refer to Annex B in the ITU Q.921 specifications for more information on all the other possible Layer 2 states such as:

• TEI_UNASSIGNED
• ASSIGN_AWAITING_TEI
• ESTABLISH_AWAITING_TEI
• AWAITING_ESTABLISHMENT
• AWAITING_RELEASE
• TIMER_RECOVERY

These states are often temporary. Use the command clear interface bri number to re-establish Layer 2 connectivity. If those states persist for extended periods use the debug isdn q921 command for further troubleshooting. A Layer 2 Status of down is indicated by Layer 2 NOT Activated. Refer to Troubleshooting BRI Layer 2 for more information on Layer 2 issues.

http://www.cisco.com/c/en/us/support/docs/dial-access/integrated-services-digital-networks-isdn-channel-associated-signaling-cas/5705-bri-sh-isdn-stat.html

regards,