[cisco-voip] Voice recording issue

Mon Oct 18 01:18:21 EDT 2010

I'm not familiar with this particular product.

But my guess is that if it is 4.1 CCM, it is probably based off packet
capturing the signalling and media off the wire.

So usually they sniff the SCCP and this signalling traffic is used to build
tables of extension numbers to device IP addresses for instance.

Typically, in your recording software you then select which extensions to
record. The software typically then applies filters to it's packet capturing
process to exclude non-interesting traffic.

In terms of recording, it also uses the SCCP sniffing to figure out when a
call is happening, and who is involved, and therefore which RTP media
packets to pluck off the wire and put into a recording file.

So recorder placement, and what traffic you have spanning to it, can be
important. i.e. you probably dont want to capture duplicate packets.

This is how it all used to work before SIP forking etc. Since you are on 4.1
think this is off the table anyway.

The key thing from the CM perspective is to make sure the recorders have
visibility of both the SCCP and RTP packets required, and as you know these
take different paths sometimes.

These products typically use common components such as WINPCAP (same as used
in Ethereal and Wireshark).

As Ahmed says, it does sound like a software issue on their side.

The fact that it is crossing calls is strange, because it means their
system, is taking audio from other conversations that it is not supposed to
be listening to. i.e. Not correlating the media streams and correct involved
call parties.

Hope that helps a bit.

Cheers,

Tim

On Sat, Oct 16, 2010 at 5:02 PM, Tahir Uddin <tahir.uddin at riyadbank.com>wrote:

>  Thanks Ahmed,
> Could this be a version incompatibility issue, we are running CM 4.1 while
> the Etalk software is one of the latest versions.
> Also, are there extenion numbers or other info in the wav files that it
> might not be able to decipher. How does it identify the packets belonging to
> one conversation?
>
> Regards
>
>
> Tahir Uddin
> Assistant Vice President / Information Technology Officer
> Information Technology Division - Mgmt.
> Information Technology Division
> Phone: +966-1-276-3000 ext. 5305
> Email: tahir.uddin at riyadbank.com
>
> **
> **
>
>
>
>  ------------------------------
> *From:* Ahmed Elnagar [mailto:ahmed_elnagar at rayacorp.com]
> *Sent:* Wednesday, October 13, 2010 6:50 PM
> *To:* Tahir Uddin
> *Cc:* voyp list
> *Subject:* RE: [cisco-voip] Voice recording issue
>
>  It must be a problem in the recording servers in interpreting the sniffed
> voice streams and reconstructing the wav files, I saw this problem a lot in
> other product and every time it happen the vendor has to change their
> code!!!
>
>
>
>  Best Regards;
>
>   Ahmed Elnagar
>
>   Senior Network PS Engineer
>
>   Mob: +2019-0016211
>
>   CCIE#24697 (Voice)
>
>  [image: ccie_voice_large.gif]
>
>
>
> *From:* cisco-voip-bounces at puck.nether.net [mailto:
> cisco-voip-bounces at puck.nether.net] *On Behalf Of *Tahir Uddin
> *Sent:* Wednesday, October 13, 2010 4:25 PM
> *To:* voyp list
> *Subject:* [cisco-voip] Voice recording issue
>
>
>
>
>
>
>
> Hi,
>
> We have call manager express and Etalk recorders
>
> We have an issue where the recording files for each call is getting mixed
> up. When agent A talks to customer A and agent B talks to customer B, in the
> recording files, we hear agent A interlaced with customer B. Has anyone come
> across this issue.
>
> I am probably not providing enough information on this, just wanted to get
> an initial take to start out.
>
>
>
> Regards
>
> Tahir
>
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