Maximum Hunt timer question

gayathridissanayaka · ‎08-28-2015

Hi,

I'm trying to understand how the Maximum hunt timer works in Hunt pilot configuration in CUCM.

My test scenario is as below;

I have an IP phone (4931) ringing in to a hunt pilot 404921 , which is pointing towards a Line group with two other IP phones with a distribution algorithm of broadcast (i.e 4921, 4901) . The ring No answer timer on the line group is set to 60 seconds. Within the hunt pilot, if there is no answer on this particular call to 404921 from 4921 and 4901 at 60 seconds, I want to forward the call to another DN, which is 4904 and I want the hunting to continue up to 10 mins on the 4904 IP phone.

My idea was that the forwarded IP phone 4904, should continue its ringing for up to 10 mins as the Maximum hunt timer is set to 600 seconds.

What I am experiencing is that within the first 60 seconds, the two IP phones4921 and 4901 rings, then the call get forwarded to the 4904 IP phone .THis will continue to ring for 5 mins and then call drops. When I looked at the traces on RTMT, I can see that the CUCM sends a Cancel request with, Reason: Q.850;cause=19 .

09089328.001 |10:10:35.481 |AppInfo |SIPTcp - wait_SdlSPISignal: Outgoing SIP TCP message to 192.168.20.34 on port 52595 index 13166
[981321,NET]
CANCEL sip:b4ec11cf-d671-9c3c-397b-f84599c6af4d@192.168.20.34:52595;transport=tcp SIP/2.0
Via: SIP/2.0/TCP 192.168.10.8:5060;branch=z9hG4bK1a8f21512e527
From: <sip:4931@192.168.10.8>;tag=400966~946f5a50-7410-423d-a5bb-36fb6cd3f0d0-44251503
To: <sip:4904@192.168.10.8>
Date: Fri, 28 Aug 2015 10:05:35 GMT
Call-ID: 51d78700-5e01326f-1a563-80aa8c0@192.168.10.8
CSeq: 101 CANCEL
Max-Forwards: 70
Reason: Q.850;cause=19
Content-Length: 0

Source Filename: SDL002_100_001133.txt.gz

PLease note that the SIP expires timer on the CUCM is set to its maximum value which is 300 seconds(5 mins) , and within the SIP profiles of the phones the INVITE expires timer is set to 3600 seconds.

My question is how does the maximum hunting timer work and the use of it, as I can see this does not seem to make any difference to the hunting time, eventhough we can set it up to 3600 seconds( 1 hour) .

Appreciate it if someone could clarify the answer to the question.

Kind regards,

G

Vivek Batra · ‎08-28-2015

Maximum hunt timer can't do what you are expecting.

It's applicable only if you have configured forward settings under Hunt Pilot and once call has been forwarded, Max Hunt Timer doesn't come into picture. Maximum Hunt Timer controls the maximum time for which Line Group members can ring.

So let say you have couple of members in Line Group with RNA timer set to xx value, but you want if no one answers the call with in yy Timer, call should forward to desired DN. Here yy is Maximum Hunt Timer.

In your example, you have set RNA value to 60 sec under Line Group and Maximum Hunt Timer as well to 60 seconds, so both of your phones will ring for 60 sec then call will be forwarded to 4904. Once call has been forwarded, there is no role of Maximum Hunt Timer.

gayathridissanayaka · ‎08-28-2015

Hi Vivek,

Thanks for the clarification. It make sense to me now.

As I'm intending to use the distribution algorithm as broadcast, I beleive that the Maximum hunt timer has no impact on this at all, and the calls will get forwarded once the RNA timer is reached ?

Thanks

G

Vivek Batra · ‎08-28-2015

Depends on whether line group members have been exhausted or maximum hunt timer expires, there are two conditions;

1. If line group members are still ringing but maximum hunt timer has been expired, it will stop ringing remaining extension and trigger call forward.

2. If all line group members have been exhausted (/or RNA timer has been expired) but maximum hunt timer is not expired yet, still it will trigger the call forward.