Where to begin troubleshooting call issue?

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Apr 28th, 2009
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We have just recently had a few complaints from one of our sites regarding some of their calls.

Apparently the users can hear the caller, but the caller cannot hear them. This happens in the middle of a call.

We're running CallManager 4.1(3) and all calls at this site are going through a single PRI.

I have no idea where to even begin looking into this issue or where to find any logs or event information for a bad call. Any help would be appreciated.

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htluo Tue, 04/28/2009 - 15:03
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Begins from the phone. When you got one-way audio (or no audio at all), it means no packets are being received.

You may either do a packet capture with sniffer software or press the question mark (?) button twice on the phone. It'll give you network statistics.



david-lima Wed, 04/29/2009 - 05:06
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Hi, for one-way audio problems, always pay attention to which direction the one-way audio is occurring, some initials steps you can check:

•Verify bidirectional IP connectivity (ping or traceroute)

•Verify configuration parameters on H.323 gateways (check if you have enable: h323-gateway voip bind srcaddr ip address, voice rtp send-recv)

•Check for NAT or firewall restrictions.

Best regards


Michael Odom Wed, 04/29/2009 - 07:11
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Double check your QoS configuration, and if you are using a service like MPLS or Metro Ethernet, check to see if you are still able to pass marked traffic over the link.

The easiest way to do a quick test is to perform an extended ping and set the TOS field appropriate to your environment. I know that TOS value 0xb8 is DSCP EF, you'll need to do a little math to determine other markings.

I would start with the extended ping to try to find any network related issues.

http://www.cisco.com/en/US/tech/tk365/technologies_tech_note09186a0080093f22.shtml -- Extended Ping reference

http://www.cisco.com/en/US/tech/tk543/tk757/technologies_tech_note09186a00800949f2.shtml -- This reference has the TOS header field to help you calculate the TOS value you need to use.


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