[VoiceOps] High Quality, Reliable Voice via the Internet / SIPNOC

Faisal Imtiaz faisal at snappytelecom.net
Mon Jun 9 19:47:34 EDT 2014

Based on what we have seen....

# 1.   Yes having better connectivity to is a given must, having the ability to change routes via multiple inbound IP Transit peers is a pre-requisite for this.

# 2.  Not sure about this, it is more likely to break stuff than reduce exposure to packet drop.

# 3. I would say this differently ,( see below).

Our Experience are as follows:-

..... Avoid Messing with the MEDIA, as much as possible.... Less number of Codec Conversions the better the quality.

Packet Loss is always a big culprit, but identifying the source of it is a bit more challenging than doing the face value troubleshooting.
 (Source of Media can be different than the perceived ITSP's network  .... )

And using devices on the Edge (customer premises, facing the provider), it is very important to have devices that will respect the DSCP/TOS tags and follow them..... Lots of device do a good job of it, and many other don't. (There is no correlation on less expensive device is not as good as a more expensive device).

The key to good quality Audio is....
   Avoid Congested Network Paths.
   Avoid Media Conversion / Codec Conversions ...
   Avoid packet drops at Customer Edge.

It is rather simple, but gets complicated in tracking down the source of the problem... Which becomes a whole different topic !


Faisal Imtiaz
Snappy Internet & Telecom

----- Original Message -----
> From: "Mark R Lindsey" <lindsey at e-c-group.com>
> To: voiceops at voiceops.org
> Sent: Monday, June 9, 2014 2:50:57 PM
> Subject: [VoiceOps] High Quality, Reliable Voice via the Internet / SIPNOC
> At SIPNOC this week, we're having a "Birds of a Feather" session on
> delivering quality voice services across the public Internet.
> A few techniques to make voice across the Internet better:
> 1. For packets from the ITSP to the customer: override the default BGP
> routing to choose an alternate route
> 2. Increase the ptime from 20 ms to 30-40 ms to reduce packet-drop exposure
> 3. EdgeWater brings us this one: actively manage TCP streams from Internet to
> CPE to provide better quality for Voice.
> So what OTHER techniques are there? Which techniques don't work?
> Yeah, it's the Internet. It's going to have failures. You're going to have
> bad days. But surely there are ways to improve the odds.
> >>> mark at ecg.co +1-229-316-0013 http://ecg.co/lindsey
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