09-14-2016 08:32 AM - edited 03-17-2019 08:05 AM
Hi,
We have an office setup with an H323 voice gateway and 4 ISDN2 lines. We currently have an issue where incoming calls will not always work.
Sometimes when the mainline is called the caller will hear the call ringing but none of the phones in the office will actually ring. I have tried replicating this and monitored it on the voice gateway using the debug isdn q931 command. When a successful call comes through I can see it process normally. When a failed call happens and it just keeps ringing I do not see the call it hit the voice gateway at all.
The telco povider has asked me if we are using point to point or point to mulit point. I have no idea how to find this out. Is anyone hear able to offer some advice?
Using CUCM 10.5
Voice Gateway is Cisco 2921 configured as H323
4 ISDN2 lines allowing 8 concurrent calls with a range of 10 DDI's
Thanks
Steve
Solved! Go to Solution.
09-15-2016 01:52 AM
I have tried replicating this and monitored it on the voice gateway using the debug isdn q931 command. When a successful call comes through I can see it process normally. When a failed call happens and it just keeps ringing I do not see the call it hit the voice gateway at all.
Then this is a ISDN side problem, rather than a H.323 side issue.
I'd start by unplugging three of the ISDNs and concentrate on just one interface. It could be that the telco has screwed up the hunting between the ISDN bearers. (Been there, done that...) If your telco is half decent, they may even have engineering numbers for each bearer that do not roll-over, so testing individual circuits is easier.
I see you've got both "isdn tei-negotiation first-call" & "isdn static-tei 0". Do you need both? On my system, I just have "isdn static-tei 0".
Also, according to Cisco's IOS doc, "isdn sending-complete" is only required in a few locations.
GTG
09-14-2016 08:46 AM
Hi Steve,
Can you attach the show run and below debug from h323 gateway for working \ non working call.
debug voip ccapi inout
debug h225 q931
debug h225 asn1
debug h245 asn1
Mention the calling \ called number for working \ non-working call.
JB
09-15-2016 12:45 AM
09-15-2016 12:55 AM
09-15-2016 02:27 AM
OK I managed to get a couple of calls where it didn't work and just kept ringing. When this happened there was no output on the debug what so ever. I am guessing this means that the call never even hit the gateway?
09-15-2016 03:56 AM
Yes, so you need to talk to your telco about where the call is going. With ISDN, their switch should know if the link is up or down, so should give N/U if all the links are down.
GTG
09-15-2016 01:32 AM
The telco povider has asked me if we are using point to point or point to mulit point. I have no idea how to find this out. Is anyone hear able to offer some advice?
I can't see how to show in on an interface, other than by looking at its configuration
#sh run int BRI0/1/0:0
....
interface BRI0/1/0:0
isdn switch-type basic-net3
isdn point-to-point-setup
isdn incoming-voice voice
GTG
09-15-2016 01:35 AM
Hi Gordon,
This is the output for the interfaces:
DUB-2921#
DUB-2921#sh run int bri0/1/0
Building configuration...
Current configuration : 247 bytes
!
interface BRI0/1/0
no ip address
isdn switch-type basic-net3
isdn tei-negotiation first-call
isdn point-to-point-setup
isdn incoming-voice voice
isdn calling-number 4850
isdn sending-complete
isdn static-tei 0
trunk-group BRI-TG 3
end
DUB-2921#sh run int bri0/1/1
Building configuration...
Current configuration : 247 bytes
!
interface BRI0/1/1
no ip address
isdn switch-type basic-net3
isdn tei-negotiation first-call
isdn point-to-point-setup
isdn incoming-voice voice
isdn calling-number 4850
isdn sending-complete
isdn static-tei 0
trunk-group BRI-TG 4
end
DUB-2921#sh run int bri0/0/0
Building configuration...
Current configuration : 247 bytes
!
interface BRI0/0/0
no ip address
isdn switch-type basic-net3
isdn tei-negotiation first-call
isdn point-to-point-setup
isdn incoming-voice voice
isdn calling-number 4850
isdn sending-complete
isdn static-tei 0
trunk-group BRI-TG 1
end
DUB-2921#
09-15-2016 01:52 AM
I have tried replicating this and monitored it on the voice gateway using the debug isdn q931 command. When a successful call comes through I can see it process normally. When a failed call happens and it just keeps ringing I do not see the call it hit the voice gateway at all.
Then this is a ISDN side problem, rather than a H.323 side issue.
I'd start by unplugging three of the ISDNs and concentrate on just one interface. It could be that the telco has screwed up the hunting between the ISDN bearers. (Been there, done that...) If your telco is half decent, they may even have engineering numbers for each bearer that do not roll-over, so testing individual circuits is easier.
I see you've got both "isdn tei-negotiation first-call" & "isdn static-tei 0". Do you need both? On my system, I just have "isdn static-tei 0".
Also, according to Cisco's IOS doc, "isdn sending-complete" is only required in a few locations.
GTG
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