Is the company’s PBX behind their firewall?  If you give it a dedicated IP 
address, then you can tag based on destination IP.

From: George Skorup (Cyber Broadcasting) via Af 
Sent: Tuesday, September 30, 2014 9:55 AM
To: [email protected] 
Subject: Re: [AFMUG] DiffServ and the internet

These are business customers with on-site PBXs with a VoIP Innovations SIP 
trunk. Yeah, if we were running a local switch, then this problem would be a 
whole lot easier to solve, but that's not what I have to work with at this 
point.

As far as I can tell, there's no easy way to identify the VoIP Innovations 
audio streams. They come from tons of different source address and use random 
ports from 10000 to 20000. And it's a mix of G711 and G729.

No idea, I'm just the network guy.

On 9/30/2014 9:28 AM, Ken Hohhof via Af wrote:

  That’s what I do, there’s another way?  We put customer ATAs on private IPs 
so it wouldn’t work if traffic bypassed our server.

  Is there a configuration parameter on the SIP trunk that tells it to send RTP 
traffic directly to the endpoint?

  We also have a multisite business customer that uses a hosted VoIP service 
(Star2Star) with an appliance at each site, we give each appliance its own 
public IP and tag traffic to those IPs.


  From: Adam Moffett via Af 
  Sent: Tuesday, September 30, 2014 9:03 AM
  To: [email protected] 
  Subject: Re: [AFMUG] DiffServ and the internet


  I've been cheating up until this point.  If you force the audio to be bridged 
through your own server then you can tag all the traffic that goes to and from 
that server.  It doesn't seem to make a huge difference versus having RTP go 
straight to the carrier.  If you're not transcoding then the added CPU usage is 
minimal.  Faxing seems to work better if I'm not bridging the audio, but why am 
I faxing anyway, right?


    I tried all kinds of stuff tonight, none were any good. I wonder if there's 
a way on MT to snoop SIP messages and look for the SIP contact IPs and mark 
those. Seems tricky. And I R no smrt enuf.

    On 9/29/2014 9:37 PM, Chris Fabien via Af wrote:

      Packet size and rate is pretty consistent right? Just a thought... 


      On Mon, Sep 29, 2014 at 8:05 PM, George Skorup (Cyber Broadcasting) via 
Af <[email protected]> wrote:

        Speaking of DSCP and carriers zeroing it in the middle, I have some 
VoIP Innovations trunks. I know where the SIP messages are coming from, so I 
can mangle a DSCP value back onto those packets at ingress. But the RTP traffic 
comes from all over the freakin place, tons of different source address, never 
the same. I've asked if they could provide a list and pretty much got a no.

        Anybody have any ideas? Any way for a MT to identify an RTP stream and 
then dynamically add a mangle rule to change the DSCP value? My MT script-fu is 
not strong.







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