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A Study of Voice over Internet Protocol

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									                                                              (IJCSIS) International Journal of Computer Science and Information Security,
                                                                                                                        Vol. 8, No. 2, 2010

                 A Study of Voice over Internet Protocol

                                                          Mohsen Gerami
                                    The Faculty of Applied Science of Post and Communications
                                         Danesh Blv, Jenah Ave, Azadi Sqr, Tehran, Iran.
                                                     Postal code: 1391637111
                                                  e-mail: artimes0@hotmail.com




Abstract—Voice over Internet Protocol, is an application that                  VoIP works in a relatively simple way. Each time you make
enables data packet networks to transport real time voice traffic.         a phone call your voice is converted into a stream of data.
VOIP uses the Internet as the transmission network. This paper             Then, rather than being sent over the phone network, this data
describes VoIP and its requirements. The paper further discusses           stream travels over your broadband internet connection.
various VoIP protocol, security and its market.
                                                                               Each data packet is labelled with its destination address (the
   Keywords: VOIP; H.323; SIP; Security; Market;                           person you're calling) and moves through the internet in the
                                                                           same way as web pages and file downloads. When they get to
                       I.    INTRODUCTION                                  their destination, the packets are reassembled and converted
                                                                           back into sound waves. When you have this process happening
    VoIP, or Voice over IP, is an application that enables data            simultaneously in two directions, you've got a phone call.
packet networks to transport real time voice traffic. It consists
of hardware and software that allows companies and persons to                  Most VoIP services also come with an allocated landline
engage in telephone conversations over data networks. As a                 phone number which allows other people to call you. In these
result, more and more companies have become interested in                  cases the call will be routed to the nearest handover point
implementing VoIP [1].                                                     (called a POP or point of presence) and then travel over the
                                                                           internet to your VoIP phone or computer [3].
     All VOIP services are not built alike. Some allow you to
call anyone with a phone, while others restrict your calls to
only other clients using the same VOIP service. You can                                     II.   REQUIREMENTS FOR VOIP
choose between three different ways to set up a VOIP system                    Obviously, the most important requirement is a broadband
on                        your                       computer.             internet connection. Broadband connections are provided by
You can use an ATA (analog voice adaptor) which performs                   cable companies (digital cable service), telephone companies
the analog-to-digital conversion, and is plugged in to your                (DSL, T1, etc.), and radio/microwave broadband internet
computer at one end and your telephone at the other.                       connections. Currently, satellite (ie., satellite uplink dish)
You can use an IP phone, a phone specifically made for use                 internet connections are not compatible with VOIP equipment
with VOIP. While the IP phone looks exactly like a normal                  because of the proprietary data compression algorithms used in
phone, it's got special Ethernet connectors that allow it to be            satellite uplink and downlink. Further, the speed of light delay
plugged into your router. They're even working on WIFI                     to and from a geosynchronous orbiting satellite would prove to
phones for VOIP that you can take with you to the various                  be very annoying people trying to talk.
internet hotspots popping up all over the world.
                                                                              Broadband connection data uplink and downlink speeds of
Finally, you can make VOIP contact with your computer alone.
                                                                           greater than 80 kilobits per second per telephone circuit (while
Simply install the VOIP software, make sure you've got a
                                                                           a call is in progress) are generally considered to be the
microphone, speakers, an internet connection (high-speed is
                                                                           minimum requirement for "decent" voice transmission quality.
best, of course), and a sound card, and chat away.
One thing many VOIP-users love about it is the cost, or more                   A "Telephone Adapter" (or "TA," and also known as an
accurately, the savings. By using VOIP you save yourself one               "Analog Telephone Adapter" or "ATA") is a piece of hardware
unnecessary bill per month - your phone bill. VOIP charges,                that is used to digitize the voice and establish the IP session to
much cheaper usually than most people's phone bills, appear on             the internet phone company’s network switch. While it is
your regular broadband bill [2].                                           possible to use a computer’s microphone and speakers and
                                                                           special software for telephony over the Internet, the obvious
    The technology underpinning VoIP was initially developed
                                                                           limitation that the computer has to be turned on to make or
in the late 1970s, but it took almost 20 years to evolve from a
                                                                           receive phone calls makes this unwieldy.
computer novelty into a household service. It's now used by
hundreds of thousands of people every day.                                    A TA eliminates the need for a computer to be up and
                                                                           running and accepts a standard 4-wire RJ11 telephone cable to




                                                                     272                               http://sites.google.com/site/ijcsis/
                                                                                                       ISSN 1947-5500
                                                             (IJCSIS) International Journal of Computer Science and Information Security,
                                                                                                                       Vol. 8, No. 2, 2010
support either premise telephone wiring or a direct connection                The above diagram illustrates a sample installation. The
of a standard analog telephone.                                           telephone on the left is directly connected to the TA, while the
                                                                          one on the right is connected to the premise distribution wiring
    In addition, the TA usually includes a built in "router" that         which is connected to the TA via RJ 11 cable to a wall jack.
provides firewall isolation for the computers connecting to the
Internet, as well as a Local Area Network (LAN) switch or                    The key to making VOIP work is the correct initialization
hub. This allows efficient Internet connection sharing. The               of the TA to work with the internet phone company and
internet phone company usually provides or rent the TA, or                configuring IP addresses on the router to use for the computer
they can be purchased at retail for a reasonable price [4].               or premise LAN connected computers sharing the broadband
                                                                          connection [6].
    The third requirement is a VoIP Service Provider (VSP)
also known as an Internet Telephony Service Provider (ITSP).
The Provider will supply you with an account and some form                                    III.   VOIP PROTOCOLS
of "Telephone Number" [5].                                                    To deliver voice, two types of VOIP protocol used: H.323
     The final requirement is one or two common variety analog            and SIP. H.323 and SIP both support VoIP and multimedia
telephone handset. Almost all commonly available wireless                 communications. H.323 is an older standard developed by the
telephones and most two line phone sets will work with VOIP               ITU. A good chunk of it is based on ISDN which comes from
[4].                                                                      the traditional telephony world. H.323 is a binary protocol and
                                                                          is fairly complex in nature. SIP was developed by the Internet
                                                                          Engineering Task Force (IETF) and is text based (similar to
A.   All together
                                                                          HTTP). Much of the infrastructure already in place to support
    First, confirm that you have the correct template for your            HTTP has been adapted to support SIP. IT managers within
paper size. This template has been tailored for output on the             businesses are generally more comfortable with SIP because
US-letter paper size. If you are using A4-sized paper, please             they are used to handling HTTP traffic. SIP is an open standard
close this file and download the file for “MSW A4 format”.                and solutions based on SIP are highly interoperable. A lot of
The TA is usually a cable or DSL router that connects to the              effort has gone into ensuring interoperability and many
cable company’s or DSL provider’s supplied terminal (or                   manufacturers work together to regularly test to ensure this.
"modem"). The customer’s computer is then connected to the                Very few manufacturers are working on new H.323
TA, as are the one or two standard (RJ11) telephone cables,               implementations. SIP has become the standard of choice and is
which connect to either a wall outlet or a standard analog                being worked on by large companies such as Microsoft and
telephone, depending on whether telephone extensions are                  Cisco [7].
present or not. More than one computer usually can be
connected to the TA to create a Local Area Network (LAN).                 A. H.323 Protocol Overview
                                                                              H.323 is a ITU recommendation based on the H.320 family
                                                                          of standards. The current version of the recommendation is
                                                                          version 4 [8]. Initially, the protocol (version 1) was designed to
                                                                          provide signalling for a multimedia conferencing system for
                                                                          LAN environments with no quality of service provisions.
                                                                          However, in is current state, it has evolved into an umbrella of
                                                                          specifications that define the complete architecture and
                                                                          operation of a multimedia conferencing system over a wide
                                                                          area packet network. In contrast to its original scope, it has
                                                                          become a scalable solution that can be interworked with
                                                                          managed large scale networks.
                                                                              A H.323 system provides the necessary signalling and
                                                                          control operations for performing multimedia communications
                                                                          over an underlying packet based network which may not
                                                                          provide a guaranteed quality of service. The actual network
                                                                          interface, the physical network and the transport protocols used
                                                                          on the network are not included in the scope of H.323. A H.323
                                                                          system comprises of the following entities: Terminals,
                                                                          Gatekeepers, Gateways, Multipoint Controllers, Multipoint
                                                                          Processors and Multipoint Control Units.
                                                                              • Terminals provide the audio/video/data communications
                                                                          capability in point-to-point or multipoint conferences, as well
                                                                          as handling the H.323 signalling issues on behalf of the user.
                                                                              • Gatekeepers provide admission control and address
                                                                          translation services
               Figure 1. A sample installation of VOIP.




                                                                    273                               http://sites.google.com/site/ijcsis/
                                                                                                      ISSN 1947-5500
                                                             (IJCSIS) International Journal of Computer Science and Information Security,
                                                                                                                       Vol. 8, No. 2, 2010
    • Gateways are needed to provide interworking with                         • A Redirect Server is a SIP server that provides address
terminals using other signalling protocols, such as PSTN                  mapping services. It responds to a SIP request destined to an
terminals, ISDN terminals, SIP terminals, etc.                            address with a list of new addresses. A redirect server doesn’t
                                                                          accept calls, doesn’t forward requests nor does it initiate any of
   • Multipoint Controllers, Multipoint Processors and                    its own.
Multipoint Control Units provide support for multipoint
conferences.                                                                 • A Proxy Server is a SIP server that acts both as a server to
                                                                          user agents by forwarding SIP requests and as a client to other
    A central aspect of H.323 is the H.323 call. It is defined as         SIP servers by submitting the forwarded requests to them on
the point-to-point multimedia communication between two                   behalf of user agents or proxy servers.
H.323 endpoints. If the H.323 endpoint communicates with an
endpoint which uses a different signalling protocol, then the                 With the exception of the user agent, which is usually part
H.323 call is defined as the call segment between the H.323               of a multimedia terminal, the rest of the logical entities
entity and the gateway that provides interworking with the                (registrar, redirect and proxy servers)a may be combined in a
foreign network.                                                          single application. Therefore, a single entity can act either as a
                                                                          proxy or as a redirect server, according to the SIP request, and
   The H.323 protocol is a tightly coupled family of sub                  at the same time accept registration requests. A SIP call is
protocols which must all interoperate in order to complete                defined as the multimedia conference consisting of all
successfully a multimedia call session. The sub protocols are             participants invited by a common source.
described in ITU recommendations. The main ones are:
                                                                              Although not partitioned formally, the SIP system can be
    • H.225: Sub protocol for messages exchanged between                  viewed as divided into domains each serviced by one
H.323 endpoints for setting up and tearing down a call as well            redirect/proxy server and one registrar. A user agent has
as for messages between an H.323 endpoint and its controlling             usually a home domain, which is specified by its address, but it
H.323 entity, such as a gatekeeper.                                       can roam and use services in other domains as well, in which
    • H.245: Sub protocol for messages exchanged between                  case it is considered to be ’visiting’. Otherwise it is considered
endpoints in order to control the call session, exchange                  to be ”at home” [9]
resource capabilities and establish media channels.
                                                                          C. Related Work- Comparison of two Protocols
    • H.235: Sub protocol for security and encryption for H.323
terminals.                                                                    The authors of Nortel Networks [11] conclude by
                                                                          recommending SIP as their preference for a control protocol.
   • H.450: Sub protocols for supplementary services, such as             They point out that even though H.323, unlike SIP, has
Call Transfer, Call Park, Call Waiting etc [9].                           currently more enterprise oriented and campus scale products
                                                                          deployed, SIP provides long term benefits which are related to
B. SIP Protocol Overview                                                  and affect time to market, extensibility, multi-party service
   SIP, which stands for Session Initiation Protocol, is an               flexibility, ease of interoperability and complexity of
IETF application layer control protocol, defined in RFC 2543              development.
[10], for the establishment, modification and termination of                  The Dalgic and Fang [12] concluded that In terms of
multimedia sessions with one or more participants. SIP makes              functionality and services that can be supported, H.323v3 and
minimal assumptions about the underlying transport and                    SIP are very similar. However, supplementary services in
network layer protocol, which can provide either a packet or              H.323 are more rigorously defined and therefore fewer
byte stream service with either reliable or unreliable service.           interoperability issues are expected to arise. Furthermore,
   A SIP system is based on a client/server model and is                  H.323 has better compatibility among its different versions and
comprised of the following logical entities:                              better interoperability with the PSTN. The two protocls are
                                                                          comparable in their QoS support (similar call setup delays, no
    • A User Agent (UA) is an application that acts on behalf of          support for resource reservation or class of service (QoS)
the user, both as a client (User Agent Client) and as a server            setting), but H.323v3 will allow signaling of the requested
(User Agent Server). As a client it initiates SIP requests and as         QoS. On the other hand, according to the paper, SIP’s primary
a server it accepts calls and responds to SIP requests made by            advantages are its flexibility to add new features and its relative
other entities. The user agent is usually part of a multimedia            ease of implementation and debugging. Finally, the authors
terminal whose media capabilities it controls without having              note that H.323 and SIP are improving themselves by learning
any media capabilities of its own.                                        from each other, and the differences between them are
    • A Registrar Server is a SIP server that accepts only                diminishing with each new version.
registration requests issued by user agents. A registrar server               The Schulzrinne and Rosenberg [13] wrote that SIP
never forwards requests.                                                  provides a similar set of services to H.323, but provides far
    • A Location Server is a server which provides information            lower complexity, rich extensibility, and better scalability.
to a proxy/redirect server about the possible current locations           They point out that future work is due to more fully evaluate
of a user. Usually, this entity is part of the proxy/redirect             the protocols, and examine quantitative performance metrics to
servers.                                                                  characterize these differences. They also imply that a study




                                                                    274                               http://sites.google.com/site/ijcsis/
                                                                                                      ISSN 1947-5500
                                                             (IJCSIS) International Journal of Computer Science and Information Security,
                                                                                                                       Vol. 8, No. 2, 2010
measuring the processing overhead of SIP and H.323, would be                 Viruses and malware
quite useful [14].
                                                                              VoIP utilization involving softphones and software are
                                                                          vulnerable to worms, viruses and malware, just like any
                        IV.    SECURITY                                   Internet application. Since these softphone applications run on
    A future expectation is that long-established security                user systems like PCs and PDAs, they are exposed and
features (i.e., authentication and encryption) will be integrated         vulnerable to malicious code attacks in voice applications.
into VoIP standards. However, today many existing data-                      DoS (Denial of Service)
centric security technologies can be utilized to enhance security
in the VoIP environment. VoIP network security includes                       A DoS attack is an attack on a network or device denying it
voice-packet security, which focuses on application concerns,             of a service or connectivity. It can be done by consuming its
while IP security focuses on transport or network security.               bandwidth or overloading the network or the device’s internal
Controlling security at these levels of the VoIP environment              resources.
may require network re-design and/or re-engineering which
                                                                             In VoIP, DoS attacks can be carried out by flooding a target
will affect the architecture of the network supporting the VoIP
                                                                          with unnecessary SIP call-signaling messages, thereby
environment. Some specific issues need further attention when
                                                                          degrading the service. This causes calls to drop prematurely
a VoIP system is deployed. It is important to remember that
                                                                          and halts call processing.
securing any network is a continual process that requires
staying abreast of the latest vulnerabilities that may exist in               Why would someone launch a DoS attack? Once the target
network infrastructure components, server operating systems,              is denied of the service and ceases operating, the attacker can
and applications deployed throughout the enterprise [15].                 get remote control of the administrative facilities of the system.
    In the early days of VoIP, there was no big concern about                SPIT (Spamming over Internet Telephony)
security issues related to its use. People were mostly concerned
with its cost, functionality and reliability. Now that VoIP is                If you use email regularly, then you must know what
gaining wide acceptance and becoming one of the mainstream                spamming is. Put simply, spamming is actually sending emails
communication technologies, security has become a major                   to people against their will. These emails consist mainly of
issue.                                                                    online sales calls. Spamming in VoIP is not very common yet,
                                                                          but is starting to be, especially with the emergence of VoIP as
    The security threats cause even more concern when we                  an industrial tool.
think that VoIP is in fact replacing the oldest and most secure
communication system the world ever known – POTS (Plain                       Every VoIP account has an associated IP address. It is easy
Old Telephone System).                                                    for spammers to send their messages (voicemails) to thousands
                                                                          of IP addresses. Voicemailing as a result will suffer. With
                                                                          spamming, voicemails will be clogged and more space as well
A. Security Threats in VoIP
                                                                          as better voicemail management tools will be required.
   Service theft can be exemplified by phreaking, which is a              Moreover, spam messages can carry viruses and spyware along
type of hacking that steals service from a service provider, or           with them.
use service while passing the cost to another person.
Encryption is not very common in SIP, which controls                          This brings us to another flavor of SPIT, which is phishing
authentication over VoIP calls, so user credentials are                   over VoIP. Phishing attacks consist of sending a voicemail to a
vulnerable to theft.                                                      person, masquerading it with information from a party
                                                                          trustworthy to the receiver, like a bank or online paying
    Eavesdropping is how most hackers steal credentials and               service, making him think he is safe. The voicemail usually
other information. Through eavesdropping, a third party can               asks for confidential data like passwords or credit card
obtain names, password and phone numbers, allowing them to                numbers. You can imagine the rest!
gain control over voicemail, calling plan, call forwarding and
billing information. This subsequently leads to service theft.               Call tampering

   Stealing credentials to make calls without paying is not the               Call tampering is an attack which involves tampering a
only reason behind identity theft. Many people do it to get               phone call in progress. For example, the attacker can simply
important information like business data.                                 spoil the quality of the call by injecting noise packets in the
                                                                          communication stream. He can also withhold the delivery of
   A phreaker can change calling plans and packages and add               packets so that the communication becomes spotty and the
more credit or make calls using the victim’s account. He can of           participants encounter long periods of silence during the call.
course as well access confidential elements like voice mail, do
personal things like change a call forwarding number.                        Man-in-the-middle attacks

   Vishing                                                                    VoIP is particularly vulnerable to man-in-the-middle
                                                                          attacks, in which the attacker intercepts call-signaling SIP
    Vishing is another word for VoIP Phishing, which involves             message traffic and masquerades as the calling party to the
a party calling you faking a trustworthy organization (e.g. your          called party, or vice versa. Once the attacker has gained this
bank) and requesting confidential and often critical                      position, he can hijack calls via a redirection server [16].
information. Here is how you can avoid being a vishing victim.




                                                                    275                               http://sites.google.com/site/ijcsis/
                                                                                                      ISSN 1947-5500
                                                              (IJCSIS) International Journal of Computer Science and Information Security,
                                                                                                                        Vol. 8, No. 2, 2010
   What Affects Voice Quality in VoIP Calls                                   Location of your hardware
   Here are the main things that affect voice quality in VoIP                  Interference is a poison for voice quality during voice
and what can be done to maximize quality.                                  communication. Often, VoIP equipment interfere with each
                                                                           other thus producing noise and other problems. For example, if
   Bandwidth                                                               your ATA is too close to your broadband router, you might
    Your Internet connection always tops the list of factors               experience voice quality problems. This is caused by electrical
affecting voice quality in VoIP conversations. The bandwidth               feedback. Try moving them away from each other to get rid of
you have for VoIP is the key for voice quality. For instance, if           the garbled calls, echoes, dropped calls etc.
you have dial-up connection, don’t expect great quality. A                    Compression: the codec used
broadband connection will work right, as long as it is not
spotty, and not shared with too many other communication                       VoIP transmits voice data packets in a compressed form, so
applications. Bandwidth dependency is besides one of the main              that the load to be transmitted is lighter. The compression
drawbacks of VoIP.                                                         software used for this are called codec’s. Some codecs are good
                                                                           while others are less good. Put simply, each codec is designed
   Equipment                                                               for a specific use. If a codec is used for a communication need
   The VoIP hardware equipment you use can greatly impact                  other than that for which it is meant, quality will suffer. [17]
on your quality. Poor quality equipment are normally the
cheapest ones (but not always!). It is therefore always good to                                  V.    VOIP MARKET
have as much information as possible on an ATA, router or IP
phone before investing on it and starting to use it. Read reviews              Telefonica has acquired VoIP provider Jajah, continuing
and discuss about it in forums. It might also be that the                  the consolidation trend in the sector. Microsoft already bought
hardware you choose is the best in the world, but still you get            Tellme, BT acquired Ribbit, Google took over GrandCentral
problems - because you are not using hardware that suits your              and KPN is buying out the minority shareholders in iBasis. In
needs.                                                                     addition, eBay sold a majority stake in Skype to Silver Lake
                                                                           Partners, which also has a stake in Avaya, while Skype and
   ATA/Router                                                              Avaya have started talks on working together. Another
                                                                           hardware manufacturer, Nortel, has received an early bid for its
   For an ATA/Router, you need to think of the following:
                                                                           VoIP assets, from Genband.
   •     Compression technologies (codecs) supported
                                                                              The trend shows newcomers slowly but surly losing their
   •     Echo cancellation, which is a mechanism for                       independence by joining larger groups. The latest takeover,
decreasing echo                                                            Telefonica's acquisition of Jajah, is perhaps the most
                                                                           remarkable in that sense, as Jajah was originally set up to avoid
   •     Firewall and security support                                     the high international tariffs charged by the incumbents.
   Phone frequencies                                                       However, Google and Skype are still maintaining their
                                                                           independence.
   The frequency of your IP phone may cause interference
with other VoIP equipment. There are many cases where                          There are still plenty of potential acquisition targets, at
people using 5.8 GHz phones have been getting voice quality                various stages of the VoIP value chain: iSkoot, Truphone,
problems. When all troubleshooting tricks failed, changing the             Jaxtr, Fring, Nimbuzz, Ooma, Vonage, 8x8 (Packet8), Rebtel,
phone to one with a lower frequency (e.g. 2.4 GHz) solved the              Freshtel, Mobivox, Sipgate, Vyke, Telio, Snapvine and many
problem.                                                                   others.
   Weather Conditions                                                          All these VoIP services providers combine infrastructure
                                                                           with services provision for end-users, and the question is what
    At times, the voice is terribly distorted by something called          the new owners will do with acquired assets. The choice comes
static, which is a small 'dirty-weed' static electricity generated         roughly down to wholesale (capacity, platform services,
on broadband lines due to thunderstorms, heavy rain, strong                software) and retail (VoIP services for end-users). BT (Ribbit)
gusts, electrical impulses etc. This static is not very much               and KPN (iBasis) are choosing clearly for the wholesale side,
noticeable when you surf the net or download files, which is               and that seems to also be the case with Telefonica (Jajah).
why we don’t complain about it when we use the Internet for                Operators as well as large corporations can be offered VoIP
data despite it be here; but when you are listening to voice, it           services based on the acquired infrastructure, platforms and
becomes disturbing. It is easy to get rid of static: unplug your           software.
hardware (ATA, router or phone) and plug it back again. The
static will be brought to naught.                                              Google and Skype represent, as 'newcomers' on the
                                                                           telephony market, the retail side. As for Jajah, the question is
    The effect of weather conditions on your connection is not             whether Telefonica will maintain the end-user services, or
something you can change. You can have some short-term                     slowly dissolve these in order to protect its own international
relief in some cases, but most of the time, it is up to your               business. There is a clear reason to keep this side of the Jajah
service provider to do something. At times, changing the cables            business though: whatever Telefonica is losing on its home
solves the problem completely, but this can be costly.                     market, it can win back abroad by competing with incumbents
                                                                           elsewhere for international business.



                                                                     276                              http://sites.google.com/site/ijcsis/
                                                                                                      ISSN 1947-5500
                                                                      (IJCSIS) International Journal of Computer Science and Information Security,
                                                                                                                                Vol. 8, No. 2, 2010
    That still leaves the question of what's the future for                      Suite, video, LTE trials and enhanced mobile IM and presence
newcomers such as Google and Skype. Pressure from VoIP                           services. The IMS market will continue to be lumpy on a
will eventually drive all call costs to the price of local calls.                quarterly basis, but we expect continued positive momentum
After deducting termination fees, there is little left over for the              from new deployments from North American cable operators,
provider. Call services will then become a true commodity                        Class 5 replacement projects in EMEA and VoLTE to
business. That's the doomsday scenario for Skype, as it mainly                   contribute to strong annual growth for at least the next five
makes money from avoiding high international call tariffs.                       years," forecasts Diane Myers, directing analyst for service
Skype will need to build up quickly a large customer base, in                    provider VoIP and IMS at Infonetics Research.
order to offset the margin erosion. For Google, this is less of a
problem, as it already has various services that do not directly                 C. IMS MARKET HIGHLIGHTS
earn money. For the incumbents, which are already seeing a
                                                                                     First, confirm that you have the correct template for
sharp decline in their international business, there is a need to
                                                                                        your paper size. This template has been tailored for
move further up the value chain. Companies such as BT and
                                                                                        output on the US-letter paper size. If you are using
Telefonica can be expected to drive innovation on the
                                                                                        A4-sized paper, please close this file and download
telephony market going forward, with especially business
                                                                                        the file for “MSW A4 format”. Worldwide IP
customers profiting. Skype may also, in cooperation with
                                                                                        Multimedia Subsystem (IMS) equipment vendor
Avaya target the business market, in order to exploit new
                                                                                        revenue totaled $426 million in 2009 and is forecast to
income sources [18].
                                                                                        grow to $1.44 billion in 2014
A. France led VoIP market in Europe in Q309                                              Following a down 3Q09, the worldwide IMS
    With more than 15 million subscribers, France is leading                              equipment market posted its strongest quarter to date,
the Voice over IP (VoIP) market in Europe. Orange France is                               jumping 92% sequentially in 4Q09
the telecom operator in Europe with the highest VoIP                                     4Q09 marked the first quarter in which revenue from
subscriber base with 6.580 million subscribers, it represents                             IMS equipment for mobile networks surpassed that of
17% of the European VoIP market.                                                          IMS equipment for fixed-line networks
   According to Dataxis Intelligence, in Q309 there were 39.7                            Alcatel-Lucent and Nokia Siemens Networks each
million VoIP subscribers. This figure includes Voice over                                 posted very strong IMS equipment results in 4Q09
DSL, Cable and Fiber. The split is 76% over DSL, 21.8% over
Cable and 2.2% over Fiber [19].                                                          With key operators and vendors forming the
                                                                                          OneVoice initiative and transferring the initiative to
                                                                                          the GSMA in February 2010, IMS is guaranteed to get
                                                                                          its biggest driver from LTE deployments starting in
                                                                                          2012




  Figure 2. VoIP market in Europe in Q309- Source : Dataxis Intelligence


B. SERVICE PROVIDER VOIP AND IMS
    "The worldwide carrier voice over IP equipment market
closed the 2009 calendar year down 28%, as expected, ending                                       Figure 3. Worldwide IMS growth.
with its third consecutive quarter of stable revenue in the fourth
quarter, led by very strong session border controller sales.
Meanwhile, the IMS equipment market ended on a high note                         D.    SERVICE PROVIDER VOIP MARKET HIGHLIGHTS
with 2009 worldwide revenue up 142% over 2008. The shining                             The worldwide service provider VoIP equipment
star in 4Q09 for IMS sales were deployments for mobile                                    market dropped 28.2% from 2008 to 2009, to $2.48
networks, particularly purchases for Rich Communication                                   billion worldwide




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                                                                                                            ISSN 1947-5500
                                                              (IJCSIS) International Journal of Computer Science and Information Security,
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       The migration to native IP sped up during the past 12           demands have to rise. A VOIP user can call any other user,
        months due to the acceleration of TDM access line               located anywhere in the world, with better voice quality. That
        loss, resulting in significant declines in TDM-related          is ideal for VOIP service. For next step the equipment will be
        equipment, particularly traditional trunk media                 more acceptable and technology has to present more power and
        gateways and softswitches                                       security enhances user’s trust.
       In 4Q09, service provider VoIP equipment revenue
        was up slightly, at 2.7% over 3Q09, continuing the                                             REFERENCES
        period of relative stability that started in 2Q09
                                                                        [1]    http://www.comtest.com/tutorials/VoIP.html
       Four vendors stood out for growing revenue in 2009:             [2]    http://articles.directorym.com/Importance_Of_VOIP-a971521.html
             o    Metaswitch in trunk media gateways and                [3]    Ian Grayson, 2009, www.cnet.com.au/voip-guide-voice-over-ip-in-
                  softswitches                                                 australia-240056481.htm
                                                                        [4]    http://www.zoesnet.net/VOIP.htm
             o    Acme Packet in session border controllers             [5]    http://www.thevoipstore.net/VoIP-Requirements.php
             o    Radisys in media servers                              [6]    http://www.zoesnet.net/VOIP.htm
                                                                        [7]    http://searchunifiedcommunications.techtarget.com/expert/Knowledgeba
             o    BroadSoft in voice application servers                       seAnswer/0,289625,sid186_gci1069115,00.html
                                                                        [8]    I. T. Union, “Packet-based multimedia communication systems,”
       GENBAND’s pending acquisition of Nortel’s CVAS                         Telecommunication Standardization Sector of ITU, Geneva,
        unit will cause some significant shifts in the vendor                  Switzerland, Recommendation H.323, Nov. 17, 2000.
        landscape, making GENBAND the largest carrier                   [9]    Papageorgiou Pavlos ,2001, A Comparison of H.323 vs SIP
        VoIP vendor in terms of overall revenue [20].                   [10]   M. Handley, H. Schulzrinne, E. Schooler, and J. Rosenberg, “SIP:
                                                                               Session Initiation Protocol,” Internet Engineering Task Force, Request
                                                                               For Comments 2543, Mar. 1999, proposed Standard.
                                                                        [11]   N. Networks, “A Comparison of H.323v4 and SIP,” 3GPP S2, Tokyo,
                                                                               Japan, Technical Report S2-000505, Jan. 5 2000.
                                                                        [12]   I. Dalgic and H. Fang, “Comparison of H.323 and SIP for IP Telephony
                                                                               Signaling,” in Proceedings of SPIE. Multimedia Systems and
                                                                               Applications II, ser. Proceedings of Photonics East, Tescher, Vasudev,
                                                                               Bove, and Derryberry, Eds., vol. 3845. Boston, Massachusetts. USA:
                                                                               The Internationl Society for Optical Engineering (SPIE), Sept. 20-22
                                                                               1999.
                                                                        [13]   H. Schulzrinne and J. Rosenberg, “A Comparison of SIP and H.323 for
                                                                               Internet Telephony,” in Proceedings ofThe 8th International Workshop
                                                                               on Network and Operating Systems Support for Digital Audio and Video
                                                                               (NOSSDAV 98), Cambridge, UK, July 8-10 1998, pp. 83–86.
                                                                        [14]   Papageorgiou Pavlos, 2001, A Comparison of H.323 vs SIP, University
                                                                               of Maryland at College Park
                                                                        [15]   DISA for the DOD, 2006, Internet Protocol Telephony & Voice Over
                                                                               Internet Protocol, Version 2, Release 2
                                                                        [16]    Nadeem Unuth, http://voip.about.com/od/security/a/SecuThreats.htm
                                                                        [17]   Nadeem Unuth, http://voip.about.com/od/voipbasics/a/factorsquality.htm
          Figure 4. Worldwide Service Provider IMS growth.              [18]   telecompaper, 2009/12/30, http://en.c114.net/583/a472219.html
                                                                        [19]   Dataxis Intelligence, 2010, http://dataxisnews.com/?p=11055
                       VI.    CONCLUSION                                [20]   Infonetics          Research        Report       Highlights,     2010,
                                                                               http://www2.marketwire.com/mw/mmframe?prid=593499&attachid=11
    VoIP is the voice of the future however many problems still                91085
remain.. VoIP phones are significantly less expensive than
traditional phone lines. VoIP companies need some methods to
make revenue, and they need a unique business plan; therefore




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