How to reduce the delay before hearing called party once the call was answered

[juan.monroy]

Hi:

I have a customer with a UC 320 + SPA303 /SPA502G phones.

Firmware version is 2.3.2 (6)

The customer complaints that whenerver a user dials an extension and the other party answer, there are a couple seconds where both cannot hear each other.

Is there a way to solve this?

Best regards,

Juan

[wenyang]

Hi Juan,

There should not be a couple seconds delay when the call is connected between internal extensions. These phones are connected to UC320W LAN port or to switch? What kind of switch do you use?

Best regards,

Wendy Yang

[juan.monroy]

Hi Wendy:

The customer is using a D-Link Switch. It is a DES-1024A 24-PORT FAST ETHERNET

Regards,

Juan

[wenyang]

Hi Juan,

Is the switch configured with VLAN 1 for data and VLAN 100 for voice? Are all phones registered to UC320W at voice VLAN 100? If yes, could you please do a TCP dump at voice VLAN 100 though Configure Utility-> Status->Support Tools-> TCP Dump-> Interface LAN Voice? You can send the TCP Dump to me directly at wenyang@cisco.com.

Can you also try to connect phones directly to UC320W if you have power adapter, and make calls to see if you experience any audio delay? Do you use any repeater in the connection?

Best regards,

Wendy

[juan.monroy]

Hi Wendy:

The swith cannot be managed. All phones are registered to UC320W for voice on range 10.1.1.X. I will send you in a separate e-mail some info.

I will run the TCP Dump next week and send it to you.

There is no repeater in teh connection.

Best regards,

Juan

[juan.monroy]

Hello Wendy:

I sent the required tcp dump to your e-mail. Awaiting for your valuable feedback...

Regards,

Juan

[ANTHONY COCCO]

Juan,

Did you ever recieve any feedback? I'm currently experiencing the same issue. My customer has a UC320 with SG500 switch and the voice delay between call transfers either inbound or internal is easily 2-3 seconds. It seems to be more an issue with the call setup. If I reset the UC320 to factory and make an inbound call, the status I see on the handset (SPA 303) when anwering a call is Answering > Connected. The call setup is quick with minimal to no audio delay. As soon I apply a basic configuration the call setup status on the handset display shows Answering > Connected > Calling > Connected. During that status shuffling is where the silence is. This occurs even when the SPA 303 phones are connected directly to the UC320 switch ports. I have an open ticket with TAC and have aleady submitted tcp dumps but the response was that there didnt seem to be an audio delay issue according to what was seen in the capture. The delay does seem less pronounced with the 2.2.2(1) firmware as opposed to the 2.3.2(6). At this point I'm still working it out with TAC and will update this post if any progress is made.

Anthony

[juan.monroy]

Anthony:

We have not reached a conclussion. The tests on the voice TCP dump have not shown any issue. I may have to run the test again. I will do so next week.

Regards,

Juan

[ANTHONY COCCO]

Juan,

I also received the same results on the voice TCP dumps I submitted to TAC. There didnt seem to be any obvious issues in the TCP dumps. My guess is that there is an audio interruption issue happening during the call connection setup process as opposed to an actual audio delay. I created the following video http://www.youtube.com/watch?v=vae-OTHqCjA for TAC to explain what the handsets are showing and how it corresponds with the audio silence. When the call is answered, the phones seem to cycle through some 1-2 seconds of call processing before the final Connected status and then the audio is able to come through. This appears to be the same for both SPA 303 and SPA 509G phones.

Anthony

[juan.monroy]

Anthony:

I believe I have exactly the same problem.

@Wendy:

Did you look at the video post from Anthony? Can you shed some lih}ght on this issue?

Regards,

Juan

[wenyang]

Hi Juan and Anthony,

The call setup status on the handset display shows Answering > Connected > Calling > Connected. It's current design. The status change should be finshed less than 1 second. Right after the status changes, the audio comes through. Do you notice obvious audio delay if you don't look at the phone LCD? If yes, how long?

Best regards,

Wendy

[ANTHONY COCCO]

Hi Wendy,

Thanks for the reply. The audio delay or silence is still obvious without looking at the display. For now I have my customer rolled back to firmware 2.2.2 (1) since the audio silence during the status changes is noticeably shorter than with 2.3.2 (6).

Regards,

Anthony