Voip

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I hope this is not too far off topic, but is anyone using Voip in a business
environment.  My small business is 4 lines plus a fax line.  I really like
all the extras companies like Vonage provides and since this business is all
phone it would be nice to be able to route numbers to a cell phone etc
easily or even take the route home and plug it into the home broadband.

I just wonder how stable 4 lines would be on DSL.

Thanks for any thoughts.



Re: Voip


You may want to experiment with it first. All the bells and whistles sound
great, problem is too often the voice quality doesn't. It seems lots of
small internet businesses use voip to keep costs down, but it seems to me,
if I have to have them constantly repeat words, it just makes for an
annoying conversation




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Re: Voip


You are probably right.  It is not the cost so much as the flexibility.
This winter when there was a couple of bad snow days I had to go to the
office even though I have Remote Desktop and can work here at home.  The
problem was no way to reroute the phones with the plain old Bell service.

With Vonage, simple to log on and reroute the phones here.  But since as a
transportation broker the phone is the business have to be sure.  It is
intriguing however.


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home



Re: Voip


With proper hardware which uses QoS (quality of service) VoIP is as good as
normal line.
Using 4 lines at once would be no problem on a fast DSL connection with no
simultaneous heavy data traffic.
However fax over VoIP is not reliable, fax machines aren't designed for data
delivered in packets.
Regards,
Martin



Re: Voip


Thanks Martin,

Just remembered - the fax line would have to stay anyway since it is the
line that the DSL is tied to.  So that leaves just the 4 lines of which the
4th line is seldom used and there is no heavy data traffic.

I put Vonage in here at home as a 2nd line just to test and play with it and
have never had any problem with voice quality.  Using cable at home which is
much faster than the DSL at the office.

I guess the only way to really know is to try it.  Can always go back if it
don't work out.


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as
data



Re: Voip


Don Harvey wrote:
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You could run a fax card in an office computer to take incoming faxes and
set the fax machine itself not to answer. Then remote in to the computer
with the fax card to retrieve the faxes.

Re: Voip


Don Harvey wrote:
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I would use a business class VoIP provider and not Vonage.

Re: Voip



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What kind of DSL?!  There are vast differences between different types
of services.

--
Best regards,   FAQ for Wireless Internet: <http://Wireless.wikia.com
John Navas      FAQ for Wi-Fi:  <http://wireless.wikia.com/wiki/Wi-Fi
           Wi-Fi How To:  <http://wireless.wikia.com/wiki/Wi-Fi_HowTo
Fixes to Wi-Fi Problems:  <http://wireless.wikia.com/wiki/Wi-Fi_Fixes

Re: Voip


John,

Just the basic DSL - I think like 384 up and 1.5 down.  I had it installed
in 1996.  There is no cable in this little strip office center even though
the houses behind my office have cable, go figure.  Cable company told me
not available.  So I am stuck with DSL and Satellite for TV.


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business
like
all



Re: Voip


Should be able to easily handle 4 VoIP lines.


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--
Best regards,   FAQ for Wireless Internet: <http://Wireless.wikia.com
John Navas      FAQ for Wi-Fi:  <http://wireless.wikia.com/wiki/Wi-Fi
           Wi-Fi How To:  <http://wireless.wikia.com/wiki/Wi-Fi_HowTo
Fixes to Wi-Fi Problems:  <http://wireless.wikia.com/wiki/Wi-Fi_Fixes

Re: Voip



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1500/384 is what we have in the office with 5 companies sharing a
single DSL line.  3 of these use VoIP service from various vendors. It
works well enough but is far from perfect.  It really depends on what
else is happening on the DSL line.  For example, I've had to impliment
QoS (quality of service) to lower the priority of bulk file transfers,
MS updates, and virus updates, because these were saturating the
bandwidth for short periods causing VoIP dropouts. Similarly, I've had
to increase the priority of VoIP service.  That worked fine until I
started using Skype Video, which again saturated the available
bandwidth.  I now have to use video after 5PM but not during business
hours.  One of the other business purchased a Polycom conferencing
system, which worked nicely if nobody else was using the DSL, but
stuttered and belched artifacts when the DSL was busy.

At this point, I'm convinced that VoIP works, but only on a
*DEDICATED* DSL line.  We're in the process of setting up a 2nd DSL
line for exactly that purpose.  My guess is approximately 12 voice
channels will be needed.  I'll probably try an Edimax load balancing
router to use the bandwidth for surfing, but my guess is the other
users will ask me to rip it out the first time it trashes one of their
phone calls.

--
Jeff Liebermann     jeffl@comix.santa-cruz.ca.us
150 Felker St #D    http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann     AE6KS    831-336-2558

Re: Voip


Thanks for the info Jeff.  From your description I think probably VoIP
should work well here.  I have 4 lines but only 3 people and for the most
part only my wife and I are doing the telephone work.  There is no heavy use
of the internet that would suck up bandwidth.

I think what I will do is go ahead and set up a single line and use it for a
while to check voice quality and ease into it.  The options available on
VoIP would really be an asset for this business.

Don Harvey
www.truckingregister.com
www.moark.us

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Re: Voip


wrote:

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In that case, you'll do fine with your existing setup.  The limiting
factor is the outgoing bandwidth and compress scheme selected.  The
worst is G.711 PCM which hogs 64Kbits/sec and is NOT compressed.  My
1500/256 Kbits/sec DSL line can handle 4 of these voice channels
before it hits saturation.  At the other end of the compression range,
we have G.723, which only requires 5Kbits/sec per voice channel, but
sounds awful.  I should have a chart somewhere.... foundit.
  G.711   PCM     64kbps   uncompressed
  G.723.1 MP-MLQ   6.4kbps compression
  G.723.1 AC-ELP   5.3kbps compression
  G.726   ADPCM   32kbps   compression
  G.728   LD-CELP 16kbps   compression
  G.729A  CS-CELP  8kbps   compression

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I think you'll find that it's just as easy to setup 2 or 4 lines for
the cost of not much more than a single line.  A big benfit of VoIP is
the incrimental cost of additional lines is minimal.

--
# Jeff Liebermann 150 Felker St #D Santa Cruz CA 95060
# 831-336-2558            jeffl@comix.santa-cruz.ca.us
# http://802.11junk.com jeffl@cruzio.com
# http://www.LearnByDestroying.com               AE6KS

Re: Voip




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use

Jeff - this is the voice bandwdith, but doesnt include the IP packet over
head.

G.711 is 80 to 84 Kbps. (as used at work on Cisco call manager).

The IP overhead is higher on the various compressed voice streams, since you
have to send packets at 20 mSec intervals, and the IP bit stays the same
size as the voice payload gets smaller.

My
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when you get to G.729A or B with 8 Kbps of voice samples, you have 24 Kbps
of actual traffic.
http://www.erlang.com/calculator/lipb /

Note - the overhead varies depending on the physical link - AFAIR this is
for Ethernet.

On DSL it will depend on the protocol stack used.
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for a
--
Regards

stephen_hope@xyzworld.com - replace xyz with ntl



Re: Voip



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Sorry.  I made some assumptions that I didn't bother detailing.  Throw
in UDP instead of TCP, silence suppression, and raw protocols.  See
below for numbers.  A better chart would be:
<http://www.voip-info.org/wiki-Bandwidth+consumption
 Codec       BR       NEB
 G.711     64 Kbps  87.2 Kbps
 G.729      8 Kbps  31.2 Kbps
 G.723.1  6.4 Kbps  21.9 Kbps
 G.723.1  5.3 Kbps  20.8 Kbps
 G.726     32 Kbps  55.2 Kbps
 G.726     24 Kbps  47.2 Kbps
 G.728     16 Kbps  31.5 Kbps
 iLBC      15 Kbps  27.7 Kbps
 BR = Bit rate
 NEB = Nominal Ethernet Bandwidth (one direction)

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I'm currently doing battle with a 7690 IP Phone.  The phone is
winning.  I'm trying to convert it to a SIP phone and TFTP update
hangs at 80% complete.  It's probably broken.

Yep.  I goofed on G.711.

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Yep.  I thought the chart looked a bit too simple.  I was in a hurry,
didn't read the associated text, wasn't paying attention, etc.  

Anyway, this is the online calculator I prefer to use:
<http://www.bandcalc.com/
Your 24Kbits/sec is for TCP.  More common is UDP requires only
16Kbits/sec for G.729b.  If I tack on silence suppression, the average
bandwidth utilization approached 9Kbits/sec while the peak bandwidth
remains at about 20Kbits/sec.  

I think (not sure) that the appropriate model for wireless is 802.3
emulation (under the link window pull down).  With G.729ab, 802.3, and
silence suppression, I get 9.6Kbits/sec average and 19.2Kbits/sec
peak.  That's not my claimed 8Kbit/sec bandwidth, but it's certainly
less than your 24Kbits/sec.

Another calculator (that doesn't have silence suppression) is at:
<http://site.asteriskguide.com/bandcalc/bandcalc.php
However, it includes the note:
  "The results obtained from the calculator should be considered
  only in one direction. In half-duplex networks, like 802.11b(Wifi),
  you should double the estimates."
which means that I also ignored the half/full duplex problem and that
all bandwidth numbers I stated should be approximately doubled for
wi-fi.  In the "L2"  pulldown menu, if I select 802.11 wi-fi, the
bandwidth numbers double.  Oh-oh.

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Yep.  802.11a/b/g wireless is encapsulated ethernet.

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Yep.  My at&t DSL is PPP over ATM (RFC1483/2684).  The "ATM tax" is
fairly heavy.  Estimating from my download speed, I get 1250 bytes
through for every 1500 I send or about 17% overhead.  Ouch.  That
doesn't show in any of the VoIP bandwidth calculators and needs to be
added.

Thanks for the correction and sorry about my screwup(s).


--
Jeff Liebermann     jeffl@comix.santa-cruz.ca.us
150 Felker St #D    http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann     AE6KS    831-336-2558

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