[-Outbound 8.1] Agent couldn't hear customer voice randomly

[pattadon]

Hi,

I got an unexpected problem that Agent couldn't hear customer voice when Outbound transfer customer to the agent.

The environment that I've are
- AudioCodes Gateway
- Outbound Contact 8.1 with Progressive Mode
- AudioCodes IP Phone

When OCS dialling to customer then transfer call to agent.
The agent will hearing only ringing tone but when they answer the call they didn't hear anything but customer still hearing our agent voice.

It's occur randomly mean that It doesn't specific to seat or ip phone.

I've tried to disable and re-enable extension but the problem still exist.

Any idea ?

[cavagnaro]

Grabs logs from AudioCodes, must be a network issue blocking some ports. And yeah, probably network guys already "said" nothing is wrong.

[pattadon]

Cavagnaro you're right, I've talked with Network guys and they said everything is working normally lol.

[kamalnba]

May be related to codec or Bandwidth. Is there any COS defined on network for voice traffic??

Sent from my SM-N910C using Tapatalk

[cavagnaro]

Codec would be a "on all calls" not random. As SDP handles this and presentation is the same for all extensions, not only one.
Bandwidth would be robotic voice at least, no random as he indicates no voice at all.

The fact your agent hears a ring is an attempt from SIP server ( I assume agents are SIP) to connect to customer leg. But customer RTP leg can connect correctly to agents PC.
Again, grab logs, do a Wireshark capture on all parts (SIP Server, Agent PC, AudioCodes) even on SIP standard messages you will find an INVITE without 200 OK.

[pattadon]

Here is the log that I captured on IP Phone.

Any suggestion ?

thanks

[url=http://postimg.org/image/epn01hkn3/]http://postimg.org/image/epn01hkn3/[/url]


Note:-
172.20.104.137 -- AudioCodes IP Phone
172.30.179.104 -- AudioCodes Gateway
172.30.181.143 -- SIP Server
172.30.181.144 -- Media Server

[abudwill]

I think I have run into this before.  My group does not directly manage our Audio Codes gateway - however I believe the resolution was an incorrect setting on the AC gateway.  I believe it was running out of some resource as a result on some phone calls - audio would not work on one leg/direction of the call.  (Would result in agent hearing customer, but customer not hearing agent).

To perform further discovery my suggestion would be to perform Wireshark capture at Media Server box and at Audio Codes box.  Wait for a bad call, examine the SIP signalling through MCP or SIP logs and go into the capture and listen to the RTP stream.  I think this will help you identify if one leg / rtp stream is missing.

[pattadon]

Hi,

I'd like to update the solution from our consult.

The problem is we using the IP phone with DHCP mode and they found some IP are duplicated due to limited IP on existing VLAN.

This problem can avoided by

1. Make sure that your IP range is enough for the devices
2. On Cisco router, there is an option called spantree portfast which should be enabled.

We using Audio codes IP phone, so when IP was duplicated, IP phone will shown an error like 30 secs.
after that the screen is back to normal. It's very difficult to see the error msg.

[cavagnaro]

but .... but... Network was perfect!! How it can be!!! 

[pattadon]

LOL