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405
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MGCP protocol operation ?

Fernando_Meza
Level 7
Level 7

Hi Netpros,

I have a situation when sometimes an inbound call attempt is dropped before the connection is established. For example ... if I called a number on my company from a mobile or public phone .. the company phone rings once and dies before I get the chance to answer it.

We have call manager 4.1 and using 2821 configured as MGCP gateways (Primary and backup) using PRI. Both gateways show registration with Call manager ok when using show ccm. Unfortunately I have not been able to reproduce the issue and at the same time debug isdn q931. Any advice or links that could help me pinpointing this issue is much appreciated.

6 Replies 6

gogasca
Level 10
Level 10

Reproduce the issue.

Detailed CCM traces

http://www.cisco.com/en/US/products/sw/voicesw/ps556/products_tech_note09186a0080094e89.shtml#subpro1

Exact CCM version

Exact Phone model and firmware

Shared lines?

Same Number?

Same B channel?

debug isdn q931

debug mgcp packet

Timestamps

IOS version

Check DSPs integrity.

http://www.cisco.com/en/US/products/hw/modules/ps2617/products_tech_note09186a008039c316.shtml

Is there an ATA involved? We have that issue with incoming calls going to An ATA first. two rings and then busy. I have to reset the switchport connected to the ATA.

No sure if this is your case.

you mean a cisco ATA Analog Telephone adaptor ..? no we don't use this,

Thanks,

Thanks,

I opened a TAC and was advised to enabled CCM detailed traces. I am currently waiting for the event to occur and will provide the logs to Cisco TAC.

Cheers,

val.mintchev
Level 4
Level 4

Greetings,

Do you have the following statements in your MGCP GW configuration?

mgcp bind control source-interface XXX

mgcp bind media source-interface XXX

I've seen issues when the MGCP traffic is not binded to a specific port.

Regards,

Val

Hi,

Yes it has binded to the loopback interface. But thanks for your comments

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