911 pots line lag

[jesse.garcia11]

Afternoon everyone. We are having issues where our users at a specific site call 911, and get a delay before the call takes off(timer starts on phone) of about 8 seconds. We have a cisco 4351 with 3 voice ports connected with three pots lines. Users are using cisco 7841 phones and our network equipment are cisco switches. Can anyone lead me into a direction to how to troubleshoot this? This will be my first time. 

Steps I have taken are bouncing the voice ports, and reloading the router. 

[TechLvr]

@jesse.garcia11 Do you have a CUCM or CME?

The issue is caused by an overlapping dial plan which triggers the interdigit timeout. In your case, the interdigit timeout is set to 8 seconds. 

Let's say you have a CUCM for your phone system. You need to look for patterns in you phone system that overlap with 911. For example, XXXX, 9XXXXXXXXXX, 91XXXXXXXXXX, 9XXXX, 9110.

Now, when you dial 911, the system waits for the interdigit timeout to expire before routing the call just in case you need to dial more digits after 911 since there are more than one matches.

To fix the issue:
1. You need to check urgent priority on all 911 patterns. 
2. While step one should resolve the issue, you need to remove / fix the overlapping patterns because it is never a good idea 

The same rules apply to CME.

[jesse.garcia11]

Oh wow ok I will start to look into this. We do have CUCM. The odd thing was that it started recently. We had a failure on the voice cards, and replaced them, then a power outage. So we thought maybe it was that. Thank You I will look into it now and post an update. 

[Nithin Eluvathingal · Accepted solution]

First check the Dialed Numbers analysis and check if there is a alternative dial plan.  Watch the video one how to do DNA .

On the  CUCM Route pattern for 911 you can select urgent Priority to process the call quickly.

On gateway check the calls are send through proper ports and calls are handled by right dial-peer.

Debug voip ccapi inout wiill give you more info from gateway. And for specific on dial peer you can use debug voip dialpeer inout

2.12.0.0

[jesse.garcia11]

Ok I am going to try this today! thank you for the details. That helps a ton

[jesse.garcia11]

How can I show the results after debug ? for the command 'debug voip ccapi inout'

[Bryson F]

I know this is not necessarily helping in the solution of this issue but there are also legal guidelines to follow pertaining to 911 with Kari's Law and Ray Baum's act I don't mean to add anything additional to your plate by any means but if you have not looked into that i would highly highly recommend that. If you already know about those laws and outlines please feel free to ignore me, it will not hurt my feelings.