Initial Voice Packets dropping

[jvankirk]

I am at my wits end here...I have three TAC cases open and no answers, so I'm coming to the boards for ideas! Has anyone experienced a problem where the first few seconds of a phone call are not heard by the users? Any thoughts on where to look?

A few pieces of information, the gateway and circuit are located locally at the site. The call manager is located remotely.

PRI<--->VoiceGateway<--->3560 Switch<---->User

                                             |

                                             | <----->ASA 5510<-----IP SEC Tunnel----->ASA 5510<---->3750<----->Call Manager

Other users who use the call manager via IPSEC do not appear to have any issues. QOS is deployed on the switches, voice gateway and on the firewalls. Both the RTP stream and the call setup are going to the priority queue on the firewall and in queue 1 on the switches. I can paste the various configurations if needed.

I've looked at QOS on the switches and everything seems to be working as it's supposed to.....but the first 10-15 seconds of calls (not all calls, it is random, but most calls) the person calling inbound can not hear the user answering the phone. I'm up for any ideas where to look....

Thanks in advance for any thoughts/ideas/help.

[Aaron Harrison]

Hi

Most likely it's a problem with whatever network (the Internet?) you are running the ASA VPN over. It sounds like you are intermittently getting high latency or packet loss on the network, and this is making the call setup (exchange of messages where each end settings on ports etc to use) take too long.

If this is the Internet or a similar, non QoS capable network your options are limited.

You would see this on the traces - have you any trace files of example calls?

Also tell us protocol you are using on the PRI.

Aaron Harrison

Principal Engineer at Logicalis UK

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[jvankirk]

Aaron,

The bandwidth is part of the problem. The customer decided to outsource their infrastructure to the cloud with no regard to additional needs. I'm trying to band-aid the situation as best I can.

Part of your reply got me to thinking...we are not putting h323 or skinny into the priority queue.

I'm thinking this might help the issue, as the traffic traverses the IPSEC tunnel. I have no traces yet. Any other thoughts on where to look?

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