What vexes VoIP users?

Scott Helms khelms at ispalliance.net
Wed Mar 2 10:15:43 CST 2011

> "What everyone is actually *selling* commercially, except for cable
> providers, is *not* VoIP; it's a subset of that: VoN; Voice Over Internet;
> where the IP transport *goes over the public internet*, and through
> whatever exchange points may be necessary to get from you to the
> provider.

Hmm, I don't know if this is a useful distinction.  I do know that is 
not the common usage for VoN.  VoN is more commonly understood to be 
Voice over Network which is a superset of VOIP rather than a subset.



> Cable companies are selling you *one hop* (maybe 2 or 3; certainly not
> 12-18), over a link with bandwidth protected from whatever may be
> going on on the Internet IP link they're also selling you; and which is
> therefore guaranteed to have better quality than whatever "VoIP" service
> it might be competing with."

That also depends.  While the most common method for cable operators is 
Packet Cable using dedicated links to and from the softswitch/session 
border controller that is by no means universal.  Here are two companies 
I know of that specialize in selling pure SIP solutions, which are often 
back hauled across the public Internet.


> I wasn't suggesting QOS.  I was suggesting *there's a completely separate
> pipe*, on non-Internet connected IP transport, carrying only the
> voice traffic, directly to a termination point, which is dedicated
> from the triple-play box and nailed up.
> Are you suggesting that's *not* how it's being done in production?

In some cases, there is a dedicated connection to the underlying 
MGCP/SIP network and in others there is not.  In some cases there is an 
MPLS connection with QoS over the public Internet and in others there is 
prioritization at all.  (I don't recommend the latter, but its usually 
an economic issue.)
> Cheers,
> -- jra

Scott Helms
Vice President of Technology
ISP Alliance, Inc. DBA ZCorum
(678) 507-5000

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