What vexes VoIP users?

Jay Ashworth jra at baylink.com
Tue Mar 1 21:51:49 CST 2011


----- Original Message -----
> From: "Scott Helms" <khelms at ispalliance.net>

> > 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.
>
> No, this incorrect. Packet Cable most certainly _is_ VOIP (a MGCP
> variant to be precise until 2.0 after which it is SIP). While a few
> providers, usually for non-technical reasons, did deploy an entirely
> separate set of downstream and upstream interfaces that is far from the
> norm. AFAIK the only top 20 MSO to do so in scale was Charter and I
> don't know if they continue that today. Comcast, the largest cable
> telephone provider certainly does not nor do providers need to since
> any Packetcable CMTS and EMTA combo offers reliable prioritization in the
> same channel(s) as the normal data path.

Indeed.  Then either Bright House is lying, their deployment was pretty 
early, or I'm nuts, cause I'm pretty certain that their early triple-
play advertising said this -- though not in so many technical words.

> > So of course Vonage and other VoN products will be less rugged.
> >
> > 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".)

> As I said, this second channel doesn't exist in almost all cases (its
> not cost effective nor needed in almost all cases). Having said that
> over the top VOIP providers do suffer in comparison because they don't
> get the benefit of prioritization in the local cable plant.

"Cost-effective"?

Could you expand on how the provisioning of a second virtual pipe down 
the hill to a cable box has any incremental costs at all?

Cheers,
-- jra




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