Reorder or fast busy tone after dial PSTN number

[SIMMN]

I have a small Pub-Sub UCM cluster in HO and Just brought up a small branch office located in another city with about 10 phones. The small branch doesnot have any UC server or voice gateway onsite. So any voice traffic, to HO extension or PSTN, has to be routed through VPN tunnel to HO first.

The HO phones are using 12xx and 13xx extensions and new branch phones are using 20xx extensions. Calls to PSTN are mostly masked with the main number.

Inter-office or extension calls are fine but call from new branch office phones to PSTN doesnot work. User mostly got reorder tone right after finish dialing the PSTN number. There are also cases that user heard the very first ring tone after dialing(recipient also got the very first ring then disconnected) then reorder tone...

The UCM is v11.5 and Voice gateway (IOS 15.1) is connected via SIP trunk to UCM and PRI to PSTN. I did SIP debugs on gateway but saw nothing interesting. I also used DNA on UCM to check the call permissions and all seem good. I do have location configured but I did configure PUB-SUB as LBM server and have the links between locations configured as unlimited...

Any idea what could be causing the issue and where should I look next?

[Andrew West]

Have you run a debug on the ISR to see whats going on from a PRI perspective?

debug isdn q931

[SIMMN]

Sorry for the delay.

I did debug isdn but not really seeing anything helpful...It seems like the issue is related to DP. If I put the phone into HO DP, all works; If I put the phone into remote branch DP, call to PSTN doesnot work anymore...

attached is the debugs for both working and not working calls from the same extension to the same PSTN number.

[Ayodeji Okanlawon]

Can you do another test call and send the following for the failing call..

debug ccsip message

can you also include the sh run of your voice gateway

[SIMMN]

New debug outputs are included.

[SIMMN]

...

[Steven Landon]

are the phones and gateway in different regions?

are you using locations based CAC?

if they are in different regions, what is the max bandwidth set to? what is the preferred CODEC for inter-region calls? your gateway is accepting G711 only

[SIMMN]

Donot think it codec or location CAC issue:

1. UCM DNA shows “ route the call”

2. 4-digit inter-site calling is fine

3. Phone and gateway are in different regions and I have the default setting for inter-region

4. I did configure unlimited for inter-location links

[Steven Landon · Accepted solution]

it is absolutely a CODEC mismatch,

CUCM defaults to G729 for inter-region calls

[SIMMN]

Cool, will tweak the codec tomorrow and report back:)

[SIMMN]

G729 is indeed the default interregion codec configured in service parameters...G711 is the default for intraregion.