Calls with "Unknown Number" drop with CUCM 7

Answered Question
Sep 7th, 2010

I have a CUCM 7 system setup with a centralized model.  2 Gateways using FXO on each gateway.  The 2 sites are connected via IPSec VPN.  When a call comes in from a number that has CallerID blocked, it manifests as "Unknown Number" on the IP Phone.  Al phones are 7970G.  Then after a brief period of time, the call is dropped.  This happens to calls coming in on either gateway, either the local gateway to the CUCM or the remote gateway.  The only calls that are dropped are those with the "Unknown Number"  all other calls process fine.  Is there something in the Service parameters that would affect this?  Or a setting on the h.323 gateways?  Any suggestions are appreciated.

I have this problem too.
0 votes
Correct Answer by dksingh about 6 years 2 months ago

Its the GW that initiates the call drop 15 secs after it connects by sending h225 RLC with cause41 (temp failure)

Sep 15 20:23:55.194: //1673/F481FAD38AE6/CCAPI/cc_api_call_disconnected:
   Cause Value=41, Interface=0x66E0B7FC, Call Id=1673

Reason seems to be that h245 msgs TCS/MSD from GW are not responded by the CCM.

Strange that it happens only for calls with no CLID.

Can u share your GW config ?

Also CCM version and If the checkbox for "Wait for far end TCS" on CUCM H.323 GW config

page is checked or unchecked?

Thanks.

DK

Correct Answer by dksingh about 6 years 2 months ago

Hello again!

You can hardcode CLID info using following CLI which will be

used for calls when telco does not deliver a name/num:

voice-port x/y/z

  station-id number 123456

  station-id name From Outside

  caller-id enable

If the issue persists, please grab following for one failed call:

deb vpm sig

deb voip ccapi inout

deb h225 asn1

deb h245 asn1

Pl. run the debugs during low traffic/maintenance as these are pretty verbose.

Thanks.

DK

Correct Answer by dksingh about 6 years 2 months ago

Hmm...not aware of any existing issue or setting as such but curious

- how long before such call drops ? Is it same duration in all/most cases?

- are u sure its just the calls with unknown number and not other calls with valid CLID?

- any reports of unknown call staying up and not dropping ?

- have u tried spoofing calline name/number (station-id name | number CLI under FXO voice-port) to see the behavior ?

- any debugs or CCM traces collected ?

Thanks!

DK

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Correct Answer
dksingh Tue, 09/14/2010 - 11:31

Hmm...not aware of any existing issue or setting as such but curious

- how long before such call drops ? Is it same duration in all/most cases?

- are u sure its just the calls with unknown number and not other calls with valid CLID?

- any reports of unknown call staying up and not dropping ?

- have u tried spoofing calline name/number (station-id name | number CLI under FXO voice-port) to see the behavior ?

- any debugs or CCM traces collected ?

Thanks!

DK

fieryhail Tue, 09/14/2010 - 12:32

Thanks for the response.  I'm quite mystified by this as well.  To answer your questions as best I can, it is appx. 25-30 seconds from the time the call comes into the h.323 gateway from the PSTN that the call is dropped.  Yes, it is the same duration in all cases.  From my understanding, it is ONLY calls with unknown CLID that are dropped, none with a valid CLID are dropped.  Yes, there have been some reports from users (rare but some) of Unknown calls staying live without dropping, however, no concrete data can be compiled as to who the callers are. 

In response to "have u tried spoofing calline name/number (station-id name | number CLI under FXO voice-port) to see the behavior ?"

I'm not sure exactly what you mean.  If you could explain more I'll either try it or let you know if I have.

No CCM traces collected as of yet, I don't see anything wrong with the debugs I've done on the router, although if you have specific ones for me to use I'll be happy to.  Thank you again for your response.

Correct Answer
dksingh Tue, 09/14/2010 - 12:38

Hello again!

You can hardcode CLID info using following CLI which will be

used for calls when telco does not deliver a name/num:

voice-port x/y/z

  station-id number 123456

  station-id name From Outside

  caller-id enable

If the issue persists, please grab following for one failed call:

deb vpm sig

deb voip ccapi inout

deb h225 asn1

deb h245 asn1

Pl. run the debugs during low traffic/maintenance as these are pretty verbose.

Thanks.

DK

fieryhail Tue, 09/14/2010 - 13:17

Thank you for your suggestions, I will try them later, after 5:30pm EST, that's when things calm down a bit.  I'll keep you updated.

fieryhail Wed, 09/15/2010 - 14:21

Sorry for the delay, here are the results.  I did try spoofing the CLID at the gateway, no difference.  The call drops regardless however it does show the "spoofed" settings so that must be working properly.  Today I isolated one of the FXO ports by temporarily removing it from the trunk group and setting the "connection plar opx" statement to the DN of a user in CUCM directly (1007). I tried an incoming call from a normal, unrestricted CLID number and the call came through, stayed on the call for appx. 4 minutes with no issue.  Then called from a restricted CLID number (cell phone) and it rang the DN1007 IP Phone perfectly, showing "Unknown Number" and when I answered it, the call would stay live for 15 seconds.  I disabled all other debug on the gateway with the exception of what you reccommended and copied the debug results for this call to a text file which I've attached to this post.  To be honest, a lot of the debug data doesn't make much sense to me, but I hope it can help!  Once again, any suggestions are greatly welcome.  I do believe at this point the issue is isolated to the h.323/FXO gateway, not CUCM.  Thanks again for any advice!

Correct Answer
dksingh Wed, 09/15/2010 - 15:11

Its the GW that initiates the call drop 15 secs after it connects by sending h225 RLC with cause41 (temp failure)

Sep 15 20:23:55.194: //1673/F481FAD38AE6/CCAPI/cc_api_call_disconnected:
   Cause Value=41, Interface=0x66E0B7FC, Call Id=1673

Reason seems to be that h245 msgs TCS/MSD from GW are not responded by the CCM.

Strange that it happens only for calls with no CLID.

Can u share your GW config ?

Also CCM version and If the checkbox for "Wait for far end TCS" on CUCM H.323 GW config

page is checked or unchecked?

Thanks.

DK

fieryhail Thu, 09/16/2010 - 10:45

Thank you for your response.  The TCS is checked on both gateways in the CUCM.  Both gateways are configured identically as well.  FXO, etc.  As far as my config for the gateways, here it is:

voice service voip

allow-connections h323 to h323

allow-connections h323 to sip

allow-connections sip to h323

allow-connections sip to sip

!

!

!

voice class codec 1

codec preference 1 g711ulaw

codec preference 2 g711alaw

codec preference 3 g723r63

codec preference 4 g726r16

voice-port 1/0/0

trunk-group POTS2

no battery-reversal

input gain 10

echo-cancel suppressor

no comfort-noise

timing hookflash-out 50

connection plar opx 1201

threshold noise -90

caller-id enable

!

voice-port 1/0/1

trunk-group POTS2

no battery-reversal

input gain 10

echo-cancel suppressor

no comfort-noise

timing hookflash-out 50

connection plar opx 1201

threshold noise -90

caller-id enable

!

voice-port 1/1/0

trunk-group POTS2

no battery-reversal

input gain 10

echo-cancel suppressor

no comfort-noise

timing hookflash-out 50

connection plar opx 1201

threshold noise -90

caller-id enable

fieryhail Thu, 09/16/2010 - 11:09

Update, I unchecked the "Wait for far h.245 TCS on both gateways in CUCM, and had a test call placed from a cell phone that as verified as "Unknown Caller" and dropped consistently after 15-30 seconds.  With that checkbox unchecked the call stayed live until it was disconnected properly from the cell phone, I had the call left live for 90 seconds.  It appears that made all the difference.  I am extremely grateful for your knowledgeable assistance sir.  My sincere gratitude!

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