VoIP Advantages and Disadvantages
The pros and cons of IP technology by
Daniel Kochmanski
DDK
Telecommunications
VoIP (Voice over Internet Protocol) is the
ability to transmit and receive voice telephone calls over an Ethernet data connection.
Ethernet data connections are used to connect computers inside an office
building across a LAN (local Area Network) also known as intranet as well as
connect computers to the world wide web (www) also known as a WAN (Wide Area
Network) or internet.
I must explain
that VoIP (Voice over Internet Protocol) is utilized in two different ways. The
first method, and the first one created, is for inbound and outbound phone
service via VoIP service providers. The service can be via SIP (Session Initiation Protocol) trunking or a VoIP adapter. The second method is utilizing
VoIP signaling directly to a business multi-line telephone is known as an IP
(Internet Protocol) based phone or IP phone for short. I
shall explain the advantages and disadvantages of IP business phones later in
this article. I’ll also explain why a Hybrid system
may be your best solution in the final paragraph.
VoIP service provider companies, such as Net2Phone
(IDT Corp) and iConnectHere (DeltaThree
Corp.), started selling VoIP phone service back in the 1990’s. My personal experience back then was that the quality was
very poor mostly due to lack of sufficient bandwidth, internet speed and
compression techniques. Today there are hundreds of VoIP phone service
providers. Some of the more popular ones are Vonage, Skype,
GoogleVoice, IPKall, Broadvoice,
AXvoice, CallWithUs,
Net2Phone, Lingo, Packet8, EarthCaller, Ooma, Oovoo and MagicJack. To utilize most VoIP phone services, you must
have high-speed internet access, unless you choose a local telecommunications
carrier such as Time Warner Digital Phone or Verizon FiOS.
The latter two own and maintain the network of lines that run directly to your
home or business which means they have full control of the voice communications
signal from your building to their Central Office equipment. This makes them the
most reliable VoIP providers. VoIP phone service will work with your existing
telephones. It can be used in either a residence or a business. One will simply
need a device called a VoIP adapter, ATA (Analog Terminal Adapter) or E-
Advantages of VoIP phone service:
One of the biggest advantages of VoIP phone
service is the low cost. The basic monthly fee and the cost per minute is lower than traditional copper POTS (Plain Old Telephone
Service) as provided by the PSTN (Public Switched Telephone Network). This is
mostly due to the lack of government control and taxes for anything related to
the internet. Unfortunately, lack of government regulation also equates to lack
of quality as you shall come to understand later. Another advantage of VoIP
phone service is free calling features. Whereas the traditional copper line
phone companies charge for features like caller ID, call forwarding, voice
mail, call waiting and distinctive ringing, VoIP service providers typically
provide these features free of charge. Also since VoIP
utilizes newer computer systems more advanced calling features are available
which cannot be obtained via traditional copper POTS lines. An example is a
videophone. A videophone provides 2-way video and audio over high-speed
Ethernet connections. Currently Skype and Oovoo are two popular videophone service providers. Soon
people all over the world will be using videophones. I
vidi people all the time. {Vidi
is pronounced vid-ee}.
Disadvantages of VoIP phone service:
1.
You must have
high-speed internet access in order to obtain VoIP phone service. This may be
via dsl (digital subscriber line), T1, cable modem
via your local cable TV provider, FiOS (Fiber Optic
Service) via Verizon or your local phone company, or some other method of high
speed internet access.
2.
You must buy or
obtain a device called a VoIP adapter, also known as an ATA (Analog Terminal
Adapter) or obtain a VoIP card for your business phone system in order to use
SIP trunks.
3.
If power is lost
to the VoIP adapter or if your internet connection is lost due to a power
outage, you will be without phone service. As opposed to copper POTS lines
which by federal law are required to have 48 hour battery backup and generators
in place in case of a long term power outage. Anyone having traditional phone
service that’s experienced a power failure knows that when the lights go out,
the hard-wired phone still works.
4.
Occasionally your
high-speed internet modem, router or VoIP adapter may lock-up. When this
occurs, one will have to unplug the power to the high-speed internet modem, the
router and the VoIP adapter. Then power them up slowly in the aforementioned
sequence in order to restore phone service. Power should be restored to the
devices in the same sequence as the signal comes into your building. Also wait
one minute between powering up each device.
5.
Potentially
Inferior Customer Service: I say potentially because
you're dealing with people at a company that’s located in another city, in
another state and/or in another country that you've probably never met. If you
have an issue with the VoIP phone service, there's only so much you can do over
the phone and internet. This also means that you will be acting as your own
troubleshooter with the aid of some technician via the phone or email. Being
that VoIP phone service frequently has problems, undoubtedly you will
experience this multiple times. One must realize that it’s helpful to have the
service provider’s company and their technicians located in the same city as
you so that they’re available to stop by if you need them. Remember that time
is money and if your VoIP phone service is down for hours or days, you must be
able to bear the expense of an outage.
6.
It may not be
possible to keep your old telephone number when you switch to a VoIP service
provider. If the service provider offers local phone numbers in your area,
there's a chance that you can keep your old phone number and port it over, but
there is no guarantee. If this is important to you, check with both your
current telephone company and the VoIP service provider to make sure you can keep
your old number.
7.
Enhanced 911
emergency services may not be available. Therefore in the event of an
emergency, if you are unable to speak, the operator will not be able to
determine your location.
8.
Your fax machine
may not work properly with VoIP phone service. Reliability varies per user and
service provider and is, at best, about 85% which
means 15% of the time your fax will not go through.
9.
Your alarm system
may not work properly with VoIP phone service. Alarm companies typically
mandate that you have a traditional copper POTS line for the alarm system to
communicate to their central office.
10.
Your other single
line analog devices such as credit card zon machines
may not work properly with VoIP phone service. This is typically due to poor
audio sampling and inband timing problems.
11.
Incomplete
outbound calls: Occasionally on a VoIP line, when one places a call he or she
may hear a ringback tone in their ear but the
recipient’s phone simply doesn’t ring. Hence the caller will think the party is
not there because they receive no answer.
12.
Occasionally one
will place a call and simply hear nothing. Yet the recipient’s phone is
ringing. The called party walks over to answer the phone and the caller hangs
up on them. The caller has to call back because they never heard any ringback tone. But at the same
time the recipient is trying to contact the caller by using *69 or the phone
number retrieved from caller ID.
13.
Incomplete
Inbound calls: Occasionally on a VoIP line, when one receives a call he or she
may hear the phone ring, answer it and no one will be there. This is typically
due to a one-way audio problem.
14.
With VoIP service
you will certainly experience a one-way audio problem at one time or another.
When this occurs, you may be able to hear the caller but he or she will not be
able to hear you or vice-versa. This can be due to NAT (Network Address
Translation) settings or STUN server settings (STUN = Simple Traversal of User
Datagram Protocol [UDP] through NATs).
15.
A dropped call is
a common problem indicative of VoIP phone service and IP phones. This can occur
anytime during the phone call and is where the phone will
simply hang-up on both parties.
16.
Your QoS (Quality of Service)
while using VoIP phone service will NOT be as good as it would be with
traditional POTS lines. VoIP phone service is similar to the quality that one
would get with a cellular phone. With a cellular phone, one would expect to
have dropped calls, digital breakup in the audio, missed calls, incomplete
calls, lost voice mails and the inability to place calls on occasion. These
same problems and many others plague any type of VoIP call.
With VoIP your voice is digitized into
packets of data (ones and zeros). These packets are split up like pieces of a puzzle,
sent over a data connection (for example, the internet), and then reassembled
at the other end. The problem, in essence, is timing. The packets must arrive
at the receiving end and be reassembled, in the exact same order, as they were
disassembled. Unfortunately, packets may take multiple different routes to get
from point A to point B hence there may be a delay of one packet over another.
When this occurs, the recipient will hear a garbled voice like: Hi Paul, Thi Dan. Are sis we still go eet
at
Advantages and Disadvantages of IP based
business phones and IP hosted solutions
As previously mentioned, one could order VoIP phone service and use it
with your existing business phone system and/or one could switch to a new phone
system using VoIP based phones also known as IP based phones. IP phones connect
directly to a computer network via Ethernet data cable. The Ethernet cables are
typically category 5e or category 6 and made of four-pair wire with RJ-45
modular plugs. The IP phones connect via a network to a main computer brain
also known as a computer server or Asterisk box. The computer server emulates a
KSU (Key Service Unit) or PBX (Public Branch Exchange). KSU and PBX are the
names of the main brain used for traditional analog and digital TDM (Time
Domain Multiplexed) type phones. KSU’s and PBX’s are
almost always located on the customer’s premises and are owned by the customer.
Whereas with the computer server for IP based phones it may be located either
on or off the customer’s premises. If it is located on the customer’s premises,
the customer’s IT (Information Technology) staff must be trained on how to
program and perform maintenance on the computer server. If the computer server
is off-site, it is called a Hosted VoIP solution. The computer server, known as
a virtual IP PBX, may be anywhere in the world. This system will require
constant maintenance, firmware & software updates. They’ll be performed by technicians
who will charge an annual fee for maintaining the system. Examples of IP based
phones where the server is on-site are Vertical Wave, Vodavi Telenium, Panasonic, Nortel and Adtran.
Hosted IP based phones is where the server is off-site. They are linked to the
virtual IP PBX via the internet. These are 100% reliant on the customer’s
internet bandwidth, speed, latency, delay, and quality of connection. Some
examples are Cisco, Polycom, Mitel,
Vaspian, I-Evolve, Aastra, and
Grandstream.
Advantages of IP based business phones
1.
There may be a
lower cost per call or cost per minute for using IP based phones than
traditional digital phones. Though it’s worth noting, that one can simply order
VoIP incoming lines to their existing digital phone system and reap the same
low cost benefits without ordering any new equipment.
2.
There may be neat
call tracking and call recording features built into the VoIP phone system. The
disadvantage is that this allows anyone off-site with technical skills the
ability to monitor your company’s calls and activity without the business owner’s
knowledge.
3.
If your IP phone computer
server is off-site, the up-front cost may be cheaper because the customer will only
have to buy phones but not a KSU or PBX. Unfortunately though, IP phones
typically cost $100 to $200 more per phone than digital phones.
4.
Soft phones, also
known as software phones, and PC phones exist which allow one’s computer to
emulate a real phone. Unfortunately the computer running the Soft phone or PC
phone can crash and force you to miss calls.
5.
IP phones can be
taken anywhere in the world and will work wherever there is an unfiltered
internet connection. This means an individual can have an IP phone at home that
is linked to their office. Though it’s worth mentioning that newer Hybrid phone
systems give the user the best of both worlds whereas they utilize traditional
reliable digital phones within the customer’s business office and still allow
IP phones to be connected to the system via the internet. With a hybrid system,
if the internet connection is lost, the customer’s office phones stay working
and only the few IP phones stop working.
Disadvantages of IP based business phones
1.
IP based phone
manufacturers are typically companies which formally only made computer data
equipment (e.g. Cisco, Linksys, Adtran,
2.
IP based phones
typically lack the one-touch buttons that are found on all digital business
phones. These one-touch buttons allow the user to access another extension or a
feature at the simple touch of a button. IP based phones may have a fancy
looking display screen but use a complex menu accessed via up, down, left and
right arrows buttons for the user to try and find the feature wanted.
3.
IP based phones
are typically reported by customers as being too complicated, full of
unnecessary features and a convoluted list of menu options. (e.g. On a
Vertical-Vodavi digital phone system a conference call can be established by
using just one button; Conference. On most VoIP based phone systems a user may need
to press 6 or more buttons to conference calls together and many VoIP phones
can only handle 2 calls at once.)
4.
Poor call quality
is commonly reported on IP based phones being that they’re plagued with the
same issues exhibited by VoIP phone service (see pages 1 and 2 above).
5.
Features, buttons
and lights may occasionally not function properly on IP based phones due to
interruptions in the Ethernet data stream. This doesn’t occur on digital phones
because each phone has a dedicated pathway (cable) back to the main phone
system
6.
Wiring for the IP
based phone is a 4-pair category 5e or category 6 cable with an RJ45 modular
plug. This means the wire is much larger than a standard thin 1 pair telephone
line cord that is common in your home and used on traditional office phones. It
also means that one may have to bear the expense of running all-new wiring
throughout their office to accommodate the new VoIP phones in order to keep the
phones on a separate network.
7.
All IP phones
require a separate 48-volt DC power source. This power may be supplied via an
expensive POE (Power Over Ethernet) switched hub or
via a power pack. If power packs are used on each phone, the phones will have 2
cords running to them and need to be located next to electrical outlets.
8.
There is no
battery backup on each of the VoIP phones. Since they are frequently connected
to an AC wall adapter, if the power goes out, your phones go dead. On digital
systems the power comes from the main KSU which typically has a battery backup
for all phones.
9.
Lack of
redundancy: When one has traditional digital phones, if the computer network
goes down it has no effect on the phone system. However, on an IP based phone
network, if the computer network crashes all the phones go dead. Conversely, if
the IP phone network crashes the computers may crash as well.
10.
On a Hosted VoIP
phone network where the main server is not on the customer’s premises (i.e.
off-site), if the internet connection is interrupted at your premise or
anywhere between you and the site of the computer server, the IP phones go
dead. This means the boss can’t even call to his secretary 15 feet away. Digital
phone systems, on the other hand, do not require internet access at all.
11.
On a VoIP phone
network where the main server is off-site, your company’s office phones and
many other company’s phones all share the same computer server so when the
server crashes, a thousand phones may go down. In addition, these systems
typically do not allow custom Auto-attendant greetings, just a generic voice
mail greeting.
12.
On a VoIP phone
network where the computer server is off-site, the customer loses control of
the main box so anything that can go wrong will go wrong. (i.e.
Server computer may crash, internet may go down, network may lock up, switched
hub may fail, router may lock-up, VoIP company may go out of business, a rogue
employee may simply turn your phones off from an alternate location, etc.) With
digital phone systems, the customer owns the main box called a KSU (Key Service
Unit) and it is in his building under his domain and control.
13.
On Hosted VoIP
phone networks your telephone numbers are ported to another city in the
14.
Potentially
Inferior Customer Service: I say potentially because,
at the end of the day, you're dealing with people at a company that’s located
in another city, in another state and/or in another country that you've
probably never met. If your company has an issue with the virtual IP PBX
system, there's only so much you can do over the phone. This also means that
your company will be paying your employees while they try to rectify the
problem with some technician via the phone. Being that VoIP phone service
frequently has problems, undoubtedly your company’s staff will experience this
multiple times. One must realize that it’s sometimes helpful to meet a person
from the company you're firm’s partnering with. It’s also imperative that the
company and their technicians be located in the same city as your company so
that they’re available to stop by if you need them. Remember that time is money
and if your IP based phone system is down for hours or days,
your company must be able to bear that expense.
15.
On Hosted VoIP
phone networks one is relying on the VoIP provider to remain in business
forever. If that VoIP provider shuts down their business, your phones go dead.
With traditional phone system, the business buys the entire phone system, has
it installed in their building and owns it. If their phone vender closes their
doors a year later, it has no effect on their phone system. The system simply
keeps working regardless of whether or not the original seller still exists.
16.
Buying Hosted
VoIP phones is similar to renting an apartment, you don’t own the main system,
there are regulations on what you can and can’t do, your rental price can
change at any time, you can be tossed out at any time, and you have to
continuously pay rental fees forever. On the other hand, as with a house that
you own, you pay one price, you own all of it, you may chose to pay in one lump
some or in payments, and once it’s paid for you never have to make another
payment.
17.
Theft of the
customer’s knowledge base or identity theft is possible on VoIP computer
servers because a log of all the customer’s
information is kept on the computer. This includes but is not limited to: the
customer’s business name, employee names, address, phone numbers, speed dial
numbers and monthly logs of all incoming and outgoing phone numbers including
extensions and any extra digits that are dialed during calls such as credit
card numbers. When this computer is accessed, the hacker, technician or law
enforcement officer will have access to all this info without your knowledge.
18.
Being that a VoIP
server is merely a computer, lack of security should be a main concern as it is
with other Internet technologies. The most prominent security issues with VoIP
are viruses, trojans, malware,
denial or theft of service, spamming, call tampering and phishing
attacks. These may occur because with VoIP a computer is used to generate,
route and control your phone service. Unfortunately with VoIP there are a
multitude of ways the digital signal can be hacked, monitored or exploited from
anywhere on the internet. Therefore, if you need your call to be private, avoid
VoIP. Digital systems on the other hand cannot be attacked with viruses, trojans, malware, etc.
19.
IP based phone
systems use a computer which emulates a traditional phone system. Why buy a
computer that emulates a phone system? Why not buy the real thing?
20.
IP based computer
servers need constant updates and maintenance. This is an annual cost which
when equated out over 5 years makes MOST IP based phone systems 2.5 times more
expensive than simply buying an actual digital phone system.
21.
If you have
Music-on-Hold or Message-on-Hold, the inbound caller may hear a hissss sound along with your outbound audio message.
22.
On a VoIP phone
network where the computer server is off-site, many different business’s phones
will be operating on the same main VoIP computer server. Therefore, the
Music-on-Hold audio may be the same for every business. A business that
currently has a customized Message-on-Hold that they paid for will not be able
to use that message.
23.
Many IP based
phone systems have no ability to connect an external paging system for shop or
office speakers. Some IP systems require an expensive analog adapter and
installation to accommodate the paging system.
24.
Many IP based
phone systems have no ability to connect an intercom door box for your front or
rear door.
25.
Some IP based
systems are now offering wireless WiFi phones.
Unfortunately due to bandwidth restrictions and interference these phones have
not been very successful in any installation.
26.
The bottom line
is that IT guys typically like IP based phone systems
because it leads to job security. They will be required to do constant
maintenance such as virus updates, computer repair and software and firmware
updates for decades to come. However, it’s worth noting, that this added
workload is the same reason that many experienced IT staff members dislike VoIP
phones. With IT people already too busy servicing their company’s computers and
network they simply don’t have the spare hundred man-hours
needed to devote to IP based computer phone systems.
If you’re considering VoIP phones, ask
your self the following questions;
1. Does your company have
multiple locations?
2. Does your company have
remote workers who need an off-site business phone?
If the answer to either of
these is yes, you’re right, you should consider some
type of VoIP solution. But keep in mind that you don’t
need to use a 100% IP based phone system nor a Hosted IP based phone system
using a Virtual IP PBX. You should consider a Hybrid system. A hybrid phone
system supports reliable traditional digital business phones and reliable
traditional analog single line telephones via a thin 1 pair wire on a phone
network that already exists in most businesses. The Hybrid system also supports
IP based internet phones and VoIP links from one company site to another via
the internet. This gives the business owner the best of all worlds. The company
can use the reliable digital business phones and analog single line telephones
within their offices, use an IP internet intercom link from office to office
and also have IP phones at the employee’s home or on the road. If the internet
connection goes down or the network fails due to a computer problem in any one
of the offices, the phones within each office will still function perfectly.
Hence, only the off-site IP phones and the intercom connection between offices will
stop functioning. Multiple manufactures make Hybrid systems. Vertical, for
example, makes the XTS-IP, the SBX-IP and the
Related Sources and Site References:
How VoIP works:
http://www.fcc.gov/guides/voice-over-internet-protocol-voip
Explanation of codecs: http://en.voipforo.com/codec/codecs-g711-alaw.php
Jitter defined:
http://searchunifiedcommunications.techtarget.com/definition/jitter
Latency defined:
http://voip.about.com/od/glossary/g/latency.htm or
http://truvoipbuzz.com/2010/07/latency-voip-explained-troubleshooting-internet-improve-voip-quality-tutorial/#
Packet Loss explained: http://www.ewp.rpi.edu/hartford/~rhb/cs_seminar_2005/SessionB3/mehta.pdf
VoIP Timing explained:
http://www.brillianttelecom.com/solutions/white_papers/
Faxing over VoIP:
http://www.soft-switch.org/foip.html
About the Author:
Daniel Kochmanski has been
working with telecommunications equipment since 1978. He has attended
Rev.