Re: Call Transfer over WAN G729 Dead Air

asharsidd · ‎02-14-2011

Hello,

I am looking into an issue for one of our customer where calls are coming into Site A and when getting transferred to Site B, the call will be transferred but the Original Calling party and the transferred party at Site B will hear dead air and call will drop in 10 sec.

Site A <> Site B ==> Codec 729ar8 (Inter-Region)

A transcoder and MTP have been added to media resource group but that doesn't help as well.

I have made a test call where the party at Site A transferred me to someone at Site B. I was at Site A gateway which is 2821 MGCP GW with 12.4(24) IOS. As he was transferring me, I did Sh voice dsp and saw the initial call leg was G711ulaw. As soon as he transferred me to Site B, I observed another call appearing in Sh voice dso with codec G729ar8. I then quickly did a Show sccp conn to verify if xcode was invoked but it says 0 sccp active connections.

Could this be an issue?

Do we need a xcoder to transfer calls (G711) across the WAN (G729)?

Please help.

asharsidd · ‎02-14-2011

Just to add to that, I changed the region codec between Site A and Site B to G711 and all worked fine and I could hear the party at Site B and Site B was able to hear me after getting a transferred call.

vasank · ‎02-14-2011

yeah..you do need a transcoder for that how are the two sites connected ..? Trunk involved..here

asharsidd · ‎02-15-2011

They are connected over an MPLS cloud.

Stuti Desai · ‎02-15-2011

Hello

To transfer a call we need a MTP. Its is because when we transfer MTP is where the call is held. Now a call manager software MTP does not support G729. You said you have a MTP in the MRGL. Which MTP is it?Call manager based or IOS based?

You said you did not see any SCCP connections so I am assuming it did not invoke any resource from the gateway.

Try configuring a IOS based software MTP and make sure you configure it for codec g729ar8.

HTH

Stuti

asharsidd · ‎02-15-2011

Thanks for that input.

I was using Software MTP and hardware Transcoder in same MRGL.

I have now added a Hardware MTP and added that in the same MRGL but it still isn't working.

MRGL-WEST >>RIG MTP (IOS)

MRG_PUB

MRG_SUB

MRG-SUB-MTP (SOFT)

MRG-TRANSCODER

Am I still making some mistake?

Thanks

asharsidd · ‎02-15-2011

just want to add to that.

Site B can transfer calls fine to Site A - no issues. If a call comes in to Site B H323 gateway, it gets transferred to someone at Site A, the call is established with no issues.

Site B is using MRGL as follows with NO transcoders.

MRGL-SiteB >> MRG-SUB-MTP (SOFT)

MRG-CHA_SUB

MRG_CHA_PUB

MRG-CHA_SUB and MRG_CHA_PUB have Software CFB and Announciator at Sub and Pub respectively.

This is working.

But same settings from Site A to Site B are not working.

Stuti Desai · ‎02-15-2011

Could you post the complete IOS version on the MGCP gateway.

I am suspecting we might be hitting the following bug CSCsc12570 because you said the transfer actually happens but then there is dead air.

Stuti

asharsidd · ‎02-15-2011

#sh ver

Cisco IOS Software, 2800 Software (C2800NM-SPSERVICESK9-M), Version 12.4(24)T, RELEASE SOFTWARE (fc1)

Technical Support: http://www.cisco.com/techsupport

Compiled Wed 25-Feb-09 17:55 by prod_rel_team

ROM: System Bootstrap, Version 12.4(13r)T, RELEASE SOFTWARE (fc1)

uptime is 12 weeks, 1 day, 20 hours, 14 minutes

System returned to ROM by power-on

System restarted at 20:09:05 GMT/BST Sun Nov 21 2010

System image file is "flash:c2800nm-spservicesk9-mz.124-24.T.bin"

This product contains cryptographic features and is subject to UnitedStates and local country laws governing import, export, transfer and

use. Delivery of Cisco cryptographic products does not implythird-party authority to import, export, distribute or use encryption.Importers, exporters, distributors and users are responsible forcompliance with U.S. and local country laws. By using this product youagree to comply with applicable laws and regulations. If you are unableto comply with U.S. and local laws, return this product immediately.

A summary of U.S. laws governing Cisco cryptographic products may be found at:

http://www.cisco.com/wwl/export/crypto/tool/stqrg.html

If you require further assistance please contact us by sending email to

export@cisco.com.

Cisco 2811 (revision 53.51) with 249856K/12288K bytes of memory.

Processor board ID FCZ1247719Q

2 FastEthernet interfaces

31 Serial interfaces

2 ISDN Basic Rate interfaces

1 Channelized/Clear E1/PRI port

DRAM configuration is 64 bits wide with parity enabled.

239K bytes of non-volatile configuration memory.

62720K bytes of ATA CompactFlash (Read/Write)

Configuration register is 0x2102

Also, just tested calls from another site - Call it Site C which has an MGCP gateway (IOS: flash:c2801-spservicesk9-mz.124-24.T2.bin) - that Site is receiving calls and can transfer calls to Site B fine with no issues. Site C in it's MRGL has just got Software MTP and a transcoder. No IOS MTP. Still calls are transferring fine.

I don't know why Calls are not transferring from Site A to Site B even I used IOS MTP.

Thanks for your valuable time.

asharsidd · ‎02-15-2011

Site C MGCP Gateway (working all fine):

Show inventory:

NAME: "chassis", DESCR: "2801 chassis"
PID: CISCO2801 , VID: V05 ,

NAME: "WIC/VIC/HWIC 1", DESCR: "2nd generation two port FXO voice interface daughtercard"
PID: VIC2-2FXO , VID: V02 ,

NAME: "WIC/VIC 2", DESCR: "2nd generation two port FXO voice interface daughtercard"
PID: VIC2-2FXO , VID: V02 ,

NAME: "WIC/VIC/HWIC 3", DESCR: "VWIC2-1MFT-T1/E1 - 1-Port RJ-48 Multiflex Trunk - T1/E1"
PID: VWIC2-1MFT-T1/E1 , VID: V01 ,

NAME: "PVDM 0", DESCR: "PVDMII DSP SIMM with Two DSPs"
PID: PVDM2-32 , VID: V01 ,

NAME: "PVDM 1", DESCR: "PVDMII DSP SIMM with one DSP with half channel capcity"
PID: PVDM2-8 , VID: V01 ,

Site A MGCP Gateway (Transfer not working - Dead air):

Show inventory:

NAME: "2811 chassis", DESCR: "2811 chassis"
PID: CISCO2811 , VID: V06 ,

NAME: "VWIC2-1MFT-T1/E1 - 1-Port RJ-48 Multiflex Trunk - T1/E1 on Slot 0 SubSlot 0", DESCR: "VWIC2-1MFT-T1/E1 - 1-Port RJ-48 Multiflex Trunk - T1/E1"
PID: VWIC2-1MFT-T1/E1 , VID: V01

NAME: "2nd generation two port BRI voice interface daughtercard on Slot 0 SubSlot 1", DESCR: "2nd generation two port BRI voice interface daughtercard"
PID: VIC2-2BRI-NT/TE , VID: V02 ,

NAME: "PVDMII DSP SIMM with Two DSPs on Slot 0 SubSlot 4", DESCR: "PVDMII DSP SIMM with Two DSPs"
PID: PVDM2-32 , VID: NA ,

NAME: "PVDMII DSP SIMM with Two DSPs on Slot 0 SubSlot 5", DESCR: "PVDMII DSP SIMM with Two DSPs"
PID: PVDM2-32 , VID: NA ,

vasank · ‎02-15-2011

could u update with show run of the gateway at site A and gateway at site B...

asharsidd · ‎02-16-2011

Hello,

I am just thinking, could it be an IOS compatibility issue?

The CCM is 7.1(3).