Guest Blogger: Russ Shaw
SearchVoIP.com welcomes Russ Shaw -- technology journalist,
author and blogger extraordinaire -- to speak his mind about
VoIP.
Read Entire Bio
10
important questions to ask your potential VoIP provider
How to
prevent and fix jitter, packet loss and latency
QoS and
The Unholy Three: Latency, jitter and packet loss
The
five most common reasons businesses deploy VoIP
First
person: My ongoing Vonage experience systems
Using
VoIP from your existing phone
Everything
you need to know about 'hooking up' (VoIP, that is)
Choosing
a VoIP provider
So
tell me: What is VoIP, anyway?
10 important
questions to ask your potential VoIP provider
19 MAY 2006 18:26 EDT (22:26, GMT)
On the
VoIP-News Web site, veteran technology author, journalist and
editor Owen Linderholm suggests 10 questions you should ask your
VoIP service provider before you sign that contract for enterprise
VoIP services.
Let's go over each of Owen's suggestions. I will add my comments
about each.
- What is the contract termination policy? Can I get out early
and what penalty is there? Are there other termination costs?
I've heard many tales of overaggressive sales types of providers
and systems integrators who will try to sweet talk potential
clients into long-term contracts. While there is some virtue of
stability to such contracts, technology, your business conditions
and even business within the VoIP industry can change during the
length of a long-term contract. OK, you can sign this contract, but
you have some leverage of your own. Ask about specific early
termination penalties, and if that sales type starts hesitating,
then you are the one with the pen in your hand.
- What startup costs are there beyond setup and equipment
fees? Besides advertised and quoted basic equipment, what else will
I REALLY need? Do I need to buy phones? Will extra
servers/cards/add-ons be needed beyond the base cost to actually
meet my usage requirements?
I've bought many cars in my time and have learned to not accept
just the bare minimum price. Once, I did so, and my car came
without a radio. Don't make the same mistake in VoIP. There's
likely to be extra server cards and phones. Get specifics on how
much equipment you'll need, and what the real cost is -- not just
some idyllic blue sky minimum.
- What day-to-day usage costs are NOT covered by my service
plan? What are the rates for international calls for example?
You don't want to find out after the fact that you are grist for
the "fee monster." I am talking about additional fees for
conference calling, long-distance calling to certain nations, and
so forth. Insist on this info ahead of time.
- Can the system as it comes handle outbound and inbound faxes
easily? Can I just plug a fax machine in or do I need special
equipment?
I hear lots of tales of woe in this area. Whether we are talking
about standalone faxes, combination multipurpose fax machines or
even internal fax modems, not all faxes work with all VoIP
technologies. Get this spec'ed out in advance.
- Do I need add-ons or extras to handle old-style analog
phones I already have or those that remote or branch offices
already have installed?
Many VoIP deployments I have witnessed and covered have been
stage-by-stage in which some company offices are fully VoIP
deployed while others are being eased in. If this is the way you
want to go about doing things, make sure that the VoIP system you
are signing on to will be able to handle your legacy analog phone
equipment.
- How does the system handle remote and mobile workers --
whether temporary or permanent? Will the experience be the same for
a telecommuter in a rural area as it is for someone at head office?
How about when I'm on the road? Are there any services or features
to handle that?
This might come as a surprise, but not all VoIP providers can
handle mobile or remote phones as an extension to the main phone
system. The most practical workaround is getting those remote
employees a single line and using your VoIP system's call
forwarding feature to bring them into your VoIP network. That
shouldn't be a problem, but neither should having to do so be a
surprise.
- If I estimate my requirements wrongly and need a major
upgrade, what will that cost me extra above if I had made the
estimate correctly to begin with? In other words, what are the
additional costs for upgrading?
In technology deployments -- as well as other things in life --
best to acknowledge the "what ifs" up front. But sometimes there is
the matter of the unforeseen. Just make sure that you have wiggle
room for adjusting the unforeseen, without having to fend off an
unanticipated fee regimen on the part of your VoIP provider.
Otherwise, you will feel like you are being punished for not
visualizing every possible circumstance ahead of time.
- How do you guarantee your quality of service? If I have
issues how do I get support, who do I contact and how fast will it
happen? When there is a complex issue and my network equipment
supplier, my broadband supplier and you are all pointing the finger
at each other. Will you step up to solve my problem?
Oh, that's a tricky one. Your service-level agreement needs to
be both specific in terms of call quality standards (latency,
jitter, packet loss), as well as in service obligations on the part
of your VoIP provider. 24/7/365 is a must.
- What about emergency services -- do you provide full 911 or
E911 services? Will dispatchers know my location automatically? How
about remote workers?
This technology is still evolving, but is essential to the
safety of your office and remote workers. Ask as specific questions
as you can with regard to how your prospective VoIP service
provider routes "911" calls made over their system. How directly or
indirectly do those calls travel to the nearest E911 emergency
response center?
- How do I know you are going to be around in two years, let
alone three?
That's a tricky one. Make sure your service contract survives
any merger, acquisition or sell-off your VoIP services provider may
be planning. I'd also do a business credit check, as well as check
technology Web sites, blogs and Internet discussion forums for any
rumors about the VoIP company you are signing up
with.
Posted by Russ Shaw
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How to prevent and fix
jitter, packet loss and latency
18 MAY 2006 16:27 EDT (20:27, GMT)
In my previous post, I wrote about the three potential
technological curses of VoIP -- latency, jitter and packet loss.
But how should you work with your VoIP provider to avoid their
onset and to fix them if they are detected by packet-measuring
software such as the one your VoIP carrier uses?
There are several such solutions, including:
- Resource reservation is a policy in place to ensure that the
VoIP call has the bandwidth needed allocated from point to point
before the conversation takes place. This cannot work on the
Internet due to external factors, but can work on a private network
where prioritization policies can be enforced where bandwidth is
reserved for sending and reception points.
- There are also network traffic tuning boxes that can be added
to a network. These can manage bandwidth uses and create QoS even
if other network devices don't support it.
- Some enterprise VoIP users opt for a hosted QoS solution from a
vendor capable of 24/7/365, real-time diagnosis, monitoring and
service.
- Other users deploy software that can automate, configure,
deploy and manage QoS in real time.
Of the three VoIP gremlins I've written about, jitter buffers have
the most specialized use. To understand why jitter buffers are
necessary, let us explore not only exactly what jitter is, but why
jitter occurs.
On the strangely named but high-quality U.K. based Web site
0xDECAFBAD.com, site owned
Bret McDanel offers an
explanation
of jitter.
VoIP packets are comprised of various bits of data.
Generally they have voice data, a RTP header (Real time protocol),
which has a UDP (User Datagram Protocol) header which has an IP
(Internet Protocol) header. The IP header is used to get the packet
to the remote machine. The UDP header tells that machine which
application to send the packet to (by way of port numbers), the RTP
header tells that application the timing interval for that packet,
and finally the voice data is used to reconstruct the analog
waveform for playback in a speaker of some sort.
All of these bits add up. An IP header with no options has 20
bytes, a UDP header has 8 bytes and an RTP (Real Time Protocol)
packet will have 12 bytes. Then there are the bytes for the actual
voice data, which varies based on which codec is used and the
settings for that codec. Each codec will take a certain amount of
voice data and compress that, typical amounts are 10-20ms of voice
per packet.
But sometimes, the system goes awry and packets fall out of rhythm.
Time for some corrective action with jitter buffers.
In a highly allegorical sense, jitter buffers are like medicine
for a snake bite -- a bit of the venom can lead to a cure.
A jitter buffer functions by isolating a small amount of the
voice data in, well, a buffer. If an errant packet arrives too
late, the jitter buffer tool will automatically discard the packet
to prevent the gap between the callers from growing. If it arrives
too quickly, it will be held for a small duration of time so that
the buffer is played to the other party at a constant rate.
Jitter buffers can, by their nature, add to the end-to-end
delay. That's why they are usually only effective on delay
variations of less than 100 milliseconds (1/10 of a second). Jitter
must therefore be minimized, ideally to 50 milliseconds or less.
There are adaptive jitter buffers that can go as high as 200
milliseconds (1/5 of a second), but that's asking a lot of the
solution.
As packets are received by the person you are speaking with,
these packets will be queued into the jitter buffer. If they are
20-millisecond samples, every 20 milliseconds the jitter buffer
will pull one packet out and play that audio data. This will
continue until the buffer is exhausted.
In this way, packets containing your voice can be reordered in
the way you sent them.
In my final post, I'll tell you how to put this all together,
and what questions you should ask your VoIP provider to ensure you
have the best quality VoIP service you can.
Posted by Russ Shaw
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QoS and The Unholy Three: Latency,
jitter and packet loss
17 MAY 2006 19:08 EDT (23:08, GMT)
QoS, or quality of service, is a VoIP performance metric any
enterprise considering VoIP should insist on. It is also a standard
that many enterprise VoIP service providers offer as part of a
service-level agreement that is part and parcel of most any VoIP
services contract.
The goal of QoS is to ensure that packet traffic for a data or
voice connection will not be delayed or dropped due to interference
from either lower priority traffic or connection degradation.
There are three main standards involved in QoS. These are
latency, jitter and packet loss. Let us take a good look at
each.
Latency
Latency is the time delay between when you say something over a
VoIP connection and when those packets are actually delivered over
the network. This is usually expressed in milliseconds (1000
milliseconds=1 second).Too much latency and your conversation
partners -- as well as you -- are likely to hear bad echoes.
Latency's handiwork can also be expressed in delays between when
something is said and when what is said is heard. Too many delays,
and you'll either wind up interrupting each other, asking each
other to repeat what they just said, or both.
The way in which the human ear and brain react to sound has a
lot to do with when the degree of latency becomes noticeable.
Neurological research has pointed to around 250 milliseconds (1/4
of a second) as the not-so-sweet spot at which roundtrip voice
delays become noticeable.
But since you don't want to cut things too closely, you should
never accept 250 milliseconds. The International Telecommunications
Union standard is 150 milliseconds, but that's one-way latency. Yet
since VoIP involves conversation back and forth -- and the
possibility that some of this conversation will be on the public
Internet rather than via private, leased lines -- you should insist
on transit latencies of much less than 150 milliseconds.
The specific latency standards often are part of service-level
agreement between you and your VoIP provider. A maximum latency of
around 50 milliseconds (about 1/20 of a second) is common.
Jitter
Now, let us take a look at jitter, which is expressed in variations
in the time delay of packet delivery. Variety may be the spice of
life, but too much jitter inconsistency, and you may hear some
weird sound effects.
In their service-level agreements, many VoIP providers now
specify maximum jitter in their SLAs. The outer range is around 2
milliseconds -- or a 1/500th of second -- variation between the
transit times of a successive series of packets containing the
digital information in a VoIP calls. Some newer SLAs have slashed
the expected performance to around 0.5 milliseconds, or 1/2000th of
a second.
Packet loss
Packet loss, as you might expect, is the failure of small groups of
digitized VoIP data to make it through the delivery process between
you and those you are speaking to over your VoIP connection. Too
much traffic in the network can cause the network to drop packets.
Packet loss of around 1% or more can be perceived during
conversation. Service-level agreements are far less tolerant of
packet loss, generally allowing for a maximum of 0.1% to 0.3% of
packets to not make it through. In other words, an SLA with, say,
0.2% packet loss means you are ensured that for every 1,000
packets, only two will fail at most.
Beyond just their good word, and your trust, how do VoIP service
providers ensure these levels of performance? What are some tools
used to measure for these metrics? If problems develop, how can
they be fixed? We'll explore these issues in our next post.
Posted by Russ Shaw
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The five most
common reasons businesses deploy VoIP
16 MAY 2006 20:48 EDT (00:48, GMT)
During my guest stint here, I have fielded a number of questions
about enterprise VoIP deployment. I've even seen a couple of
inquiries about how to make the best case for VoIP to senior
managers or execs.
Well, now I have some information for you -- direct from an
objective survey of those organizations that have made the decision
to deploy VoIP.
Last week, Infonetics
Research released a study entitled "Drivers For VoIP
Deployment." To determine these drivers, Infonetics conducted
in-depth interviews with 240 small, medium and large organizations
that use VoIP products and/or services now or will by 2007, as well
as 450 shorter interviews to determine VoIP adoption rates.
Most respondents use in-house VoIP, some use managed VoIP
services and others use a combination of the two.
Infonetics quizzed respondents on 12 possible reasons for
deploying VoIP. Of these 12 reasons, five received more than 50%
scores on the question as to whether the reason was "definitely a
driver" to deploying VoIP.
Here are the five reasons, the percentage each of them garnered
in the survey, plus my commentary about each.
- Integrated phone system across multiple locations: 64%.
VoIP equipment and management software makes it possible to
distribute phone systems, virtual switchboards and related call
management and administrative functions pretty much anywhere
regardless of location. This integration bridges geographical
separation so efficiently that best practices VoIP installations
are geographically transparent.
- Scalability: 58:%. Because little if any extra wiring is
necessary, unlike traditional telephony, it is relatively easy to
add additional phones to your VoIP setup or even additional nodes
to your network. Frequent user scenarios for this would be adding
additional employees who need to be on the VoIP network, or even
adding additional branch offices to your existing VoIP offering as
you open or expand those remote facilities.
- Operational costs: 57%. Plainly put, VoIP saves you a
bundle over traditional phone toll charges. In the case histories I
write for a leading VoIP industry trade magazine about VoIP
deployments, I hear tales of phone bills being cut by as much as
80%.
- Consolidate voice and data networks: 56%. In VoIP, voice
and data travel across networks as bits. This commonality promotes
ease of systems administration.
- Flexibility: 55%. That relates to the ability of VoIP to
be retrofitted to new, as well as existing, office and mobile
communications environments. Mobile users can easily be outfitted
with VoIP that they can use through a secure Wi-Fi connection or
over their laptop through the company's virtual private
network.
Here are the other seven reasons cited in the "Drivers For VoIP
Deployment" survey results, all of which are useful to make the
case for VoIP:
- Ease of use/manageability: 50%
- Cost per user: 47%
- Applications and features: 45%
- (Previous phone) system has reached end-of-life: 44%
- Disaster recovery: 40%
- Employee mobility/flexibility: 40%
- Open standards-based: 29%
Our next column is going to be about a fairly unglamorous but
absolutely essential regimen of enterprise VoIP: testing and
measurement.
Posted by Russ Shaw
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First person: My
ongoing Vonage experience
15 MAY 2006 15:26 EDT (19:26, GMT)
Rather than simply rattle off a list of VoIP providers and their
services, I thought I would write about the service that is both
the largest and the one I use directly.
Vonage is the largest North American VoIP provider by subscriber
count. I have been a Vonage customer for years, and use both their
standard and "softphone," software-based service.
Of their four phone-based (as opposed to PC-based) services, I'd
recommend checking out either the $24.99 Premium Unlimited Plan,
for home use, or the $49.99 a month Vonage Small Business Unlimited
Plan -- a good plan for SMBs.
With Vonage Premium Unlimited, (my plan, incidentally) you get
unlimited local and long distance calls anywhere in the US, Canada,
Puerto Rico and select European countries, as well as features
including Voicemail Plus, 3-way calling, call waiting and call
forwarding caller ID with name and 911 dialing.
Additionally, if you sign up directly from the Vonage Web site
(as opposed to a third-party distributor), you'll get a free phone
adapter.
Small Business Unlimited gives you all that, plus a dedicated
fax line thrown in.
The SoftPhone plan is $9.99 a month. For that, you get 500
included minutes, but there's a catch. Since this is an add-on
plan, you have to already have a Vonage account, with a phone
number. And you'll get a second Vonage phone number exclusively for
the SoftPhone.
In my 18 months or so as a Vonage user, I have found many things
to like and a few characteristics of the service that could stand a
bit of improvement.
Installation, which I described in an earlier post, was easy and
straightforward. Recapping:
- Connect one end of your Ethernet network cable to one of
the numbered ports on the back of the router. Connected the other
end of your Ethernet cable to the Ethernet port on the back of your
PC.
- Hook up one end of your phone cable to the back of your
phone, and the other end to the phone port on the back of your
router.
- Power your cable modem back on, leaving your PC powered
off (for the moment).
- Connect your power adapter to your broadband router's
power port.
- Plug the other end of the power adapter into a nearby
electrical outlet. When you made the connection, the Power LED
(Light Emitting Diode) will light up.
- Turn your PC back on.
As for my phone number, I opted to let Vonage assign me a new one.
That's because I only have a cell and not a landline -- the latter
of which could be more easily replaced by a Vonage account. But
that solution is not for everyone.
The smart part of simply moving your phone number from your
existing carrier to your new VoIP carrier (in this case, Vonage) is
that it's likely lots of folks have your existing number. Do you
really want to call everyone up and say, "Here's my new phone
number"? It can be a pain, and because you are changing carriers,
it is unlikely your "jilted," former carrier will happily program a
number change announcement complete with your new number.
The number-reassignment process can take a while, too. I have
heard tales of an existing number transfer between an existing
carrier (such as Verizon) to Vonage taking several weeks. Usually,
the fault is red tape and paperwork. Fortunately, I hear of more
instances where it takes just a week or less.
As one who likes to keep a detailed record of all my phone
calls, I find that Vonage's Dashboard -- accessible via
password-protected login from the Vonage site -- is an excellent
way to do this. I can see a record of all my calls, to what number
they were placed or from where they originated, and how long they
lasted. I often cut and paste results from my Dashboard into an
Excel file I keep with detailed records and commentary about all my
calls.
The info you can extract from the Dashboard is not as complete
as some third-party VoIP calling record utilities, but should
suffice for most business and home users. I'll get into some of
these products in a future post.
When we get down to call quality, I have to tell you, though,
that on average, my Vonage calls sound just a little less robust
than traditional land-line calling does. On about one out of four
calls, I hear my caller or the person I am calling mention about
some sort of an echo. Infrequently, I experience garble when I use
my Vonage SoftPhone. I have diagnosed the problem and it seems to
be one of a lack of system resources. I often have a dozen or so
software programs open at a given time -- and frequently several
instances of Word and Internet Explorer. That's a memory drain.
Time for a new computer soon.
As to Vonage customer service, I have not had to deal with them
in quite some time. I have heard complaints that at least the
initial service level of Vonage support is of varying quality and
varying understandability. Fortunately, for Vonage users, there's a
viable alternative -- the non-Vonage affiliated,
Vonage Forum. With some
27,000 registered users including some real brainy ones, you can
almost always get your question answered there. And answered for
free, without having to remain on hold like you do with Vonage's
customer support.
Next column, we'll explore the appeal of VoIP to the enterprise.
We'll parse the results of a just-released study that treats the
issue in depth.
Posted by Russ Shaw
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Using VoIP from your existing
phone
12 MAY 2006 16:48 EDT (20:48, GMT)
In today's post, we will talk about some of the basics you need to
know before you sign up for the type of VoIP service that, with
some additional equipment, lets you make and receive VoIP calls
over your existing service.
In VoIP, phone calls are routed over your high-speed cable or
DSL (Digital Subscriber Line) Internet connection. With few
exceptions (such as "soft phone" services I will describe in a
subsequent post later this week) you talk over your regular phone,
which is hooked up to a PC. A broadband router, most of which cost
less than $100, is attached to your PC as well.
As you may already know, the "Internet protocol" reference in
"VoIP" describes the way in which packets (small groups of bits and
bytes) are sent and received over the Internet. This packet
transfer happens when you download a Web page or send and receive
e-mails. The process also occurs with calls you make over the
Internet, which are translated into packets of data and then
re-interpreted back to sounds (and in some cases, video as well) at
your recipient's PC.
There are a couple of drawbacks, however. If your cable modem or
DSL service goes down, so will your VoIP connection. And although
the technology is improving, VoIP services do not work well for
emergency "911" calls.
Sounds expensive, but it isn't. In fact, most of the more than
400 or so VoIP-service providers in North America (which include
some traditional phone companies such as Verizon and AT&T)
charge either a flat monthly $19.95 to $29.95 fee for unlimited
national and some international calling, or assess just a few cents
per minute for each call.
The signup and setup processes for these services follow a
common -- if not identical -- model. Before you get started, you'll
want broadband Internet access. VoIP calls won't work over dial-up,
because dial-up doesn't involve the exchange of Internet packets
directly via the Internet, but through a phone line that connects
to it. To put it another way, VoIP requires your phone to talk. If
you are on dial-up, your phone modem will already be chattering
away, making conversation just about impossible.
OK, so you have broadband. Now you are ready to get started.
First you, the prospective customer, should perform your due
diligence by researching the various VoIP service providers and
plans available in your area. Listings and reviews of these
services appear regularly in the consumer technology press, as well
as in the mainstream media.
If you identify a service you would like to sign up with, you
can either call them directly or, in most cases, sign up via their
Web site. There, you will be asked to input your zip code. If
service is available in your city, you'll be taken through a series
of screens where you enter your basic contact info, credit card
data and preferred billing plan.
In my next post, I will describe the process involved in hooking
up VoIP service. Then, in the post after that, I'll compare several
of the leading VoIP services -- most of which I have tested
extensively.
Posted by Russ Shaw
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Everything you need
to know about 'hooking up' (VoIP, that is)
11 MAY 2006 18:38 EDT (22:38, GMT)
In today's post, we'll discuss the general procedure involved in
hooking up VoIP service from the point after you complete your
order on the VoIP service provider's Web site.
When you complete the sign-up process, you will be given a new
phone number. This number will not replace your existing number
given to you by your local phone company. It will simply be the one
offered by your new VoIP provider. Your new number will work with
your existing phone just as your old number does. For example, when
someone calls you at your new VoIP connection, your phone will ring
just as if your caller dialed your existing phone number. It's just
that when the call travels to your phone, it will come to that same
phone over the Internet, not that copper wire connection.
Most service providers will offer you a broadband router. If you
already have a router provided to you by your cable company, you
are probably OK. Still, some newer routers come with enhanced
functionalities. If your router is two years old or more, consider
replacing it with a router sold or provided by your new VoIP phone
company.
A few days or at most a week after you complete your order, your
VoIP equipment will arrive at your home or office. In the box,
you'll find a broadband router, a power adapter for the router,
along with a phone cable and Ethernet cable. Of course, you'll also
see a standard welcome kit. The kit usually comes with an
installation manual for your router and cable, an installation CD
that helps you configure your VoIP setup, as well as cards that
illustrate how to sign up for extra services such as voice mail,
caller ID, call waiting, call forwarding and enhanced "911"
emergency services. Unlike more familiar phone companies, most VoIP
providers offer these provisions for free or for a very inexpensive
price.
Now is time for the installation process. For most VoIP
services, the setup procedure is fairly standard and involves the
following steps:
- Connect one end of your Ethernet network cable to one of the
numbered ports on the back of the router. Connected the other end
of your Ethernet cable to the Ethernet port on the back of your
PC.
- Hook up one end of your phone cable to the back of your phone
and the other end to the phone port on the back of your
router.
- Power your cable modem back on, leaving your PC powered off
(for the moment).
- Connect your power adapter to your broadband router's power
port.
- Plug the other end of the power adapter into a nearby
electrical outlet. When you made the connection, the power LED
(Light Emitting Diode) will light up.
- Turn your PC back on.
For each service I tried (and will review in the next post), my
next step was to go to their Web site and complete the signup
process I started when I first ordered my equipment. This meant
configuring the router I had just installed to work with the
service I was signing up for. The procedure involved entering a
default local IP address (such as http://192.168.15.1, for the
Linksys router Vonage sent me), and then parading through several
screens where I entered a username and password, and then selected
an IP address automatically through my current Internet Service
Provider -- in my case, Comcast.
Posted by Russ Shaw
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Choosing a VoIP
provider
10 MAY 2006 16:09 EDT (20:09, GMT)
Business users who are considering signing up with VoIP services
essentially have three general classes of options. These options
are:
- Contracting with an enterprise-class VoIP service (such as
Level 3, Global Crossing and Voxeo). These are carriers that often
work in partnership with providers of VoIP equipment you will be
using at your office or in your network, such as those of Cisco and
Avaya.
- Signing up with a business-class flavor of VoIP service offered
by brands more familiar to the consumer VoIP space. Examples
include Vonage, SunRocket and 8x8 (more commonly referred to as
Packet 8), as well as VoIP offerings from broadband access
providers such as Comcast, Verizon, AT&T and Earthlink.
- Working with newly enhanced PC to PSTN (public switched
telephone network) offerings from companies whose voice
transmission roots were in the computer-to-computer space but have
recently expanded to allow calls to and from their users to
standard phone numbers. Examples of these include Skype, Yahoo
Messenger with Voice and Google Talk.
I will be writing detailed entries on each of these options. Since
the purpose of today's column is to provide an overview, though,
let us briefly go over the advantages and disadvantages of each
VoIP provider option.
Enterprise VoIP carrier -- This is the most expensive
option, but by far the most scalable as you grow your business. In
most cases, these VoIP calls travel over proprietary networks
rather than the public Internet. Networks are configured to be
compatible with sophisticated VoIP analysis and measuring tools.
Most of the VoIP services carried over these networks are also
compatible with IP PBX solutions that provide an unsurpassed level
of call-control, call tracking and caller management. Service
agreements with this level of provider almost always have QoS
(Quality of Service) written into these contracts. Plus, you get a
level of direct, on-premise expertise that few of the consumer
grade carriers offer.
Business-class consumer carrier -- These calls are highly
likely to travel over the public Internet, and as such are limited
by the degree and speed of Internet connectivity at any one time.
Because of this, ironclad, true QoS support is uncommon. Tech
support is often limited to help desks, often situated thousands of
miles away from your premises. Although tech support offered by
such providers has been improving due to enhanced remote
diagnostics, you don't get the same degree of hand-holding an
enterprise VoIP carrier offers. The advantages are transportability
-- such as when you move your office -- and, of course, price.
PC-to-PSTN carrier -- Great for consumers, these products
are most certainly the least robust and dependable of options
available to the enterprise. Nevertheless there are a definite
advantages besides price. Some of the software used in these
networks has been architected to offer video or audio conference
calling for dozens of participants at rates dramatically lower than
a standard conference bridge. These calls can be set up with
virtually no lead time. Since these carriers are PC-based, they
require far less hardware, an advantage for crowded or
under-powered office environments. The software that powers these
offerings can easily be loaded onto notebook computers, allowing
for your mobile workforce to be integrated into your VoIP
setup.
Posted by Russ Shaw
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So tell me: What
is VoIP, anyway?
09 MAY 2006 20:28 EDT (00:28, GMT)
Today, let's discuss what VoIP (Voice over Internet Protocol) is,
and how the equipment you use in a VoIP call helps the technology
work for you.
The basic concept of VoIP involves sending and receiving calls
over the Internet or any Internet Protocol (IP) network. This is
accomplished by converting voice traffic, such as the words you
say, into data packets.
These data packets are then routed over the Internet in the same
way as other data- -- such as this article -- are. When these data
packets arrive at their intended destination (such as the person
you are calling), the communications equipment at the other end of
the call takes these data packages, reassembles them and then
converts them back into your voice.
There are basic types of ways to make and receive VoIP
calls.
An Analog Terminal Adapter (ATA) performs the data packet
translation I have just mentioned. With an ATA you connect your
existing phone to your computer or even to your Internet
connection. You then sign up with a service that is ATA-based. You
usually also get software you install on your PC that enables you
to control various functions of your call setup (such as number of
rings callers get before voicemail kicks in). Setup is quick and
generally quite uncomplicated.
An IP phone physically resembles a regular phone with buttons, a
cradle and a receiver/handset. But there's more here under the
hook. Your standard phone comes with RJ-11 phone connectors, but
your IP phones have an RJ-45 Ethernet connector. This is used to
connect your phone directly to your router. Now, we are even seeing
Wi-Fi IP phones that can pick up a Wi-Fi service signal and use
that to connect.
Computer-to-computer VoIP services involve software from a VoIP
provider, an account with that provider, as well as gear such as a
microphone, speakers and in most cases, a headset. Many of these
services are integrated with instant messaging utilities, enabling
you to send and receive IMs at the same time you are talking over
your VoIP connection. These calls are either free to other
subscribers of the same computer-to-computer service, or are just
two to three cents a minute to many nations.
Posted by Russ Shaw
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This blog originally appeared on
TechTarget's
Expert Answer Center as a post in Russ Shaw's VoIP blog. Russ
served as the
on-demand expert on the Expert Answer Center for two weeks in
May, during which he was available to quickly
answer questions on Voice over IP as well as to write
daily blog entries. Keep an eye on the Expert Answer Center for
topics that could help your IT shop.