[Asterisk-Users] ISDN BRI vs. VOIP DID's, is it worth it?

[Walt Reed]

On Sun, Apr 17, 2005 at 01:50:56PM -0700, snacktime said:
> On 4/17/05, Gregory Wiktor - ADCom Corp. <gw at adcomcorp.com> wrote:
> > I have been trying a did company for a few days. I find the service
> > decent, but sound quality only moderate.
> > 
> > Rather than spending 35 or so for monthly with did, I am considering an
> > isdn bri at this location.
> > 
> > How much more stable and reliable is bri or pri versus a voip did
> > service?  I like the concept of a bri more, but I do not get cid
> > generation.  Would anyone suggest bri over voip where available?
> > 
> > I must say, I prefer higher voice quality.  If anyone finds bri to be
> > worth it (at about 54/month plus usage) please let me know what you
> > think.
> 
> I'm kind of asking the same questions myself right now.  I think it
> depends a lot on what you are planning on using voip for.  I also
> think that you are going to see reliability go up and up over the next
> year or two, so you have to take that into account also as you plan
> your infrastructure.   I think new installations should at least be
> voip capable.

No matter what the usage is, BRI / PRI will be more reliable. VoIP to a
generic providor will never be as reliable as a dedicated connection to
your telco carrier of choice. Now whether you can live with the level of
reliability is another story :-)

The big problem with with VoIP is lack of QoS beyond your local network.
Probably the best situation is to get your VoIP from your local ISP
where QoS can be implemented end to end. Other current VoIP issues
include spotty Fax support and flakey SIP / IAX support - these should
be resolved in time, but they are a big problem now (as the volume of
emails on this list related to providor problems shows.) As for QoS
support on ther internet in general, well, I wouldn't hold my breath,
and that is what is really needed to increase reliability / sound
quality.

> Right now I would not rely on voip 100% for something business
> critical.  Personally I'm looking at using voip but having adequate
> pstn access as a backup, with the incoming DID numbers being able to
> automatically route to the pstn in case of failure.    I know I can do
> this if my numbers are 800 numbers, but I've still not found a way to
> do this with local number DID's, although I'm still looking.
> 
> Reliability on incoming lines is a lot more difficult to deal with
> then outgoing.  As long as you * server has connectivity, you could
> have 4-5 different providers in your dialplan and have it cascade down
> through them on failure.   Wish it was that easy with DID's.

True, if the providor is totally down you can fail over, but if the
providor is up but not working well, you will have sound quality
problems, dropped calls, etc. and there isn't a good way of handling
this at the moment (could probably handle this via some new * code to
"score" a providor during a call and drop them from the list if there
are too many dropped packets, etc.)