What vexes VoIP users?

Michael Thomas mike at mtcc.com
Tue Mar 1 08:53:49 CST 2011


On 03/01/2011 05:51 AM, Jay Ashworth wrote:
> ----- Original Message -----
>    
>> From: "William Pitcock"<nenolod at systeminplace.net>
>>      
>    
>> That is the same market Vonage is now targeting in the US, basically.
>> National calling in the US is basically bundled with most calling plans
>> now. I'm not convinced that many people use Vonage in the US - my
>> experience with it was that it was not as reliable as the VOIP
>> products offered through the various broadband providers I have had.
>>      
> Let us be clear: if you're getting "digital telephone" service from a
> cable television provider, it is *not* "VoIP", in the usage in which
> most speakers mean that term -- "Voice Over Internet" is what they should
> be saying, and cable-phone isn't that; the voice traffic rides over a
> separate DOCSiS channel, protected from both the Internet and CATV
> traffic on the link.
>    

Er, I'm not sure what the difference you're trying to make.
Is IP running over an L2 with a SLA any less "IP" than one
without a SLA? That's all the DOCSIS qos is: dynamically
creating/tearing down enhanced L2 qos channels for rtp
to run over. It's been quite a while since I've been involved,
but what we were working on with CableLabs certainly was
VoIP in every respect I can think of.

| As I recall, this questionably fair competitive advantage has been
> looked into by ... someone.  (Cablecos won't permit competing VoIP
> services to utilize this protected channel, somewhere between "generally"
> and "ever".)
>    

There's is a great deal of overhead involved with the booking
of resources for enhanced qos -- one big problem is that it
adds quite a bit of latency to call set up. I'm sceptical at this
point that it makes much difference for voice quality since voice
traffic is such a tiny proportion of traffic in general -- a lot has
changed in the last 15 years. Now video... I'm willing to believe
that that enhanced qos still makes a difference there, but
with youtube, netflix, etc, etc the genie isn't getting back in
that bottle any time soon. So Moore's law is likely to have the
final word there too making all of the docsis qos stuff ultimately
irrelevant.

Mike




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