IP TELEPHONY BASED SERVICES
Md. Khurshaduzzaman Razib
Id # 071404056
Dr. Mashiur Rahman
NORTH SOUTH UNIVERSITY
What we understand by IP Telephony is the protocols, mechanisms, and applications by
which voice conversations which are traditionally done using dedicated circuit switched
networks are done using IP data networks. That is a revolutionary invention in
telecommunication industry. It has not only introduced cheap or almost free national and
international call it has introduce lots of new services in terms of telecommunication.
A major development starting in 2004 has been the introduction of mass-market VoIP
services over broadband Internet access services, in which subscribers make and receive
calls as they would over the PSTN. Full phone service VoIP phone companies provide
inbound and outbound calling with Direct Inbound Dialing. Many offer unlimited calling
to the U.S., and some to Canada or selected countries in Europe or Asia as well, for a flat
monthly fee. These services take a wide variety of forms which can be more or less
similar to traditional POTS. At one extreme, an analog telephone adapter (ATA) may be
connected to the broadband Internet connection and an existing telephone jack in order to
provide service nearly indistinguishable from POTS on all the other jacks in the
residence. This type of service, which is fixed to one location, is generally offered by
broadband Internet providers such as cable companies and telephone companies as a
cheaper flat-rate traditional phone service. Often the phrase "VoIP" is not used in selling
these services, but instead the industry has marketed the phrases "Internet Phone",
"Digital Phone" or "Softphone" which is aimed at typical phone users who are not
necessarily tech-savvy. Typically, the provider touts the advantage of being able to keep
one's existing phone number.
At the other extreme are services like Gizmo Project and Skype which rely on a software
client on the computer in order to place a call over the network, where one user ID can be
used on many different computers or in different locations on a laptop. In the middle lie
services which also provide a telephone adapter for connecting to the broadband
connection similar to the services offered by broadband providers (and in some cases also
allow direct connections of SIP phones) but which are aimed at a more tech-savvy user
and allow portability from location to location. One advantage of these two types of
services is the ability to make and receive calls as one would at home, anywhere in the
world, at no extra cost. No additional charges are incurred, as call diversion via the PSTN
would, and the called party does not have to pay for the call. For example, if a subscriber
with a home phone number in the U.S. or Canada calls someone else within his local
calling area, it will be treated as a local call regardless of where that person is in the
world. Often the user may elect to use someone else's area code as his own to minimize
phone costs to a frequently called long-distance number.
Corporate customer telephone support often use IP telephony exclusively to take
advantage of the data abstraction. The benefit of using this technology is the need for
only one class of circuit connection and better bandwidth use. Companies can acquire
their own gateways to eliminate third-party costs, which is worthwhile in some situations.
They can also have lots of other features like
Traditional PBX features (call forwarding, call hold, speed dial….)
- Interactive Voice Responses, including voice mail, auto attendant, and IVR creation
- Contact Center (Automatic Call Distribution)
- Conferencing (n-way and bridge)
- CTI applications (Centile’s CallPad, VoicePad, SwitchBoard)
- Presence Management
- Instant Messaging
- Service creation APIs to develop additional IVRs and IP telephony enabled
A growing number of organizations use real-time communications, or synchronous
conferencing -- chats, instant messaging, VoIP and video conferencing -- to hold online
meetings with volunteers, to allow volunteers to interact with staff, clients, or each other,
or to have live, online, real-time events, where volunteers listen or watch a featured
speaker or guest.
These forms of real-time, synchronous communications add a new dimension to the
Internet and remote volunteer experience. For instance, one-on-one instant messaging
between a volunteer and staff member can often solve problems more quickly than email-
only communications. The dialogue from written real-time communications is easily
archived for later reference. Video conferencing puts voices and faces to volunteers and
their email addresses. Many of the applications give a more emotional, "human" feel to
interactions, as seen in the opening statement to this page. Live, instantaneous
interactions, together with email and other asynchronous tools, can help strengthen the
bonds among participants and help build community.
Telemedicine has been used to support care at a distance through the use of expensive
equipment and broadband communication links. In the past, the operating room has been
an isolated environment that has been relatively inaccessible for real-time consultation.
Recent technological advances have permitted videoconferencing over low-bandwidth,
inexpensive Internet connections. If these connections are shown to provide adequate
video quality for surgical applications, low-bandwidth telemedicine will open the
operating room environment to remote real-time surgical consultation.
Surgeons performing a laparoscopic cholecystectomy in Ecuador or the Dominican
Republic shared real-time laparoscopic images with a panel of surgeons at the parent
university through a dial-up Internet account. The connection permitted video and audio
teleconferencing to support real-time consultation as well as the transmission of real-time
images and store-and-forward images for observation by the consultant panel. A total of
six live consultations were analyzed. In addition, paired local and remote images were
“grabbed” from the video feed during these laparoscopic cholecystectomies. Nine of
these paired images were then placed into a Web-based tool designed to evaluate the
effect of transmission on image quality.
Distance learning overcomes geographical barriers in sparsely populated areas and makes
it possible to achieve economy-of-scale without localizing all participants. In particular,
distance learning allows for increased selection of courses and curriculums and promises
increased teaching quality as more people have access to more qualified
The use of IP multicast in distance learning achieves increased scalability as there is no
longer a centralized bottleneck or a possible single point of failure that all media and
control must pass through. Our multicast protocol moreover enables end users and
senders to use commodity equipment and standard desktop applications for reception,
encoding and streaming of media. The SLIM TMP protocol also has built-in support for
reaching end users not directly connected to a multicast capable router and for coping
with NAT’s and firewalls as we describe in .
We have recognized three scenarios where multicast is exploited for distance learning
where the level of feedback and interaction between senders and receivers and the delay
tolerated are the primary separators:
I. Content distribution: A distribution from a multimedia server to multiple receivers.
This can be exploited to distribute a prerecorded educational material, Internet radio or a
high quality TV stream. A modest delay, such as from sender or receiver buffering, can
easily be tolerated.
II. Live distribution: A live distribution from a lecturer to multiple students. From a
multicast perspective this is just like a content distribution from a multimedia server but
this introduces certain real time constrains that needs to be met. Feedback from receivers
(e.g. students) can be achieved with a chat room or a messenger application. This is a
good choice when the students are at home with limited equipment and bandwidth. A
small delay can be tolerated if the interaction among the group is message based.
III. Fully interactive teleconference: A teleconference where all participants can send
and receive audio and video streams. In this setup students can ask questions and
participate in discussions as on site. A fully interactive distribution has stronger real time
constraints than a content distribution and only a very small delay can be tolerated by
users in a live conversation. For example, in a telephone conversation the maximum
tolerated end-to-end delay is generally not more than 100 ms.
A distance learning session can be a combination of the three scenarios described above
where, for example, a slide show or a video is sent to all participants in a fully interactive
conference with a content distribution.
Implementing IP technology in contact center results in numerous cost saving benefits.
With IP telephony, application and application infrastructure is less complex resulting in
lower capital expenditures and ongoing maintenance and support costs than with
traditional voice systems. Also, integration is rapid and functionality can be phased using
a modular approach while virtualization makes contact center functions available to more
workers. This enables companies to get more accomplished with less staff support. Other
cost saving benefits includes an increase in customer loyalty because the caller is
connected to the right agent at the right time and a global approach using contact center
agents from around the world.
Municipalities and other governmental entities tend to have multiple departments and
locations running on disparate – and often incompatible – technology infrastructures.
This can, and often does, pose significant maintenance and support challenges.
The adoption of IP telephony creates a single virtual telephony environment for various
departments spread throughout the city – or country. By unifying voice and data
technology infrastructures, maintenance and support are greatly simplified. Furthermore,
a single network can provide virtually every city employee with traditional telephone
services as caller ID, call forwarding, voice mail, and advanced directory service – plus
advanced IP telephone capabilities such as auto attendant, “follow me” messaging,
message forwarding to off-system users, and centralized directory integration.
By combining multiple network infrastructures into a single IP-based network, financial
institutions can consolidate disparate infrastructures and reduce communications costs. At
the same time, those savings can be transferred back to customers in the form of more
competitive products such as Internet banking and bill pay, and offering value-added
services such as wealth management and online trading and trade monitoring. Using IP
telephony solutions, banks can move all channels into the branch, reducing manual cash
handling by tellers, and providing an additional delivery mechanism for enhanced
customer service. The result: simpler operations, lower maintenance and support costs,
and greater agility.
The manufacturing industry is using IP telephony to speed up time to market and to
balance supply and demand. The technology lowers the risk of unpredictable demand,
uncertain availability, and fluctuating prices for direct materials by speeding up the
communication process between distributors and suppliers. Industries like automotive,
retail, pharmaceuticals, and high-tech are realizing dramatic improvements in inventory,
service levels, supply and demand variability, and distribution channels through
converged voice/data systems. Manufacturing organizations also realize savings in long-
distance rates and can leverage multiple mobile communication and productivity
solutions. Instead of expensive PBX equipment at every office site, centralized IP
telephony solutions provide cost-effective central management and support.
Many telecommunications companies are looking at the IP Multimedia Subsystem (IMS)
which will merge Internet technologies with the mobile world, using a pure VoIP
infrastructure. It will enable them to upgrade their existing systems while embracing
Internet technologies such as the Web, email, instant messaging, presence, and video
conferencing. It will also allow existing VoIP systems to interface with the conventional
PSTN and mobile phones.
Some Apps Enabled by IMS
Push to X: Talk, watch, text, and stream
Instant Conferencing: Voice, video, IM, chat
Messaging: Voice, video, IM, unified …
Gaming: Multiparty, mobile, combined with chat, voice, IM
IP Centrex: Hosted PBX, virtual receptionist, personal assistant
PIM: Calendars, alerts, personalized announcements, active phonebooks
Combinational Services: voice + video sharing; chat + gaming; message + calendar
Presence: Find me / Follow me
Location Based Services: Find nearest X.
Sometimes called Radio Over Internet Protocol or RoIP, Amateur radio has adopted
VoIP by linking repeaters and users with Echolink, IRLP, D-STAR, Dingotel and EQSO.
In fact, Echolink allows users to connect to repeaters via their computer (over the
Internet) rather than by using a radio. By using VoIP Amateur Radio operators are able to
create large repeater networks with repeaters all over the world where operators can
access the system with actual ham radios.
Ham Radio operators using radios are able to tune to repeaters with VoIP capabilities and
use DTMF signals to command the repeater to connect to various other repeaters, thus
allowing them to talk to people all around the world, even with "line of sight" VHF
Click-to-call is a service which lets users click a button and immediately speak with a
customer service representative. The call can either be carried over VoIP, or the customer
may request an immediate call back by entering their phone number. One significant
benefit to click-to-call providers is that it allows companies to monitor when online
visitors change from the website to a phone sales channel.
After a lots debate about voip legalization good news is that Bangladesh Govt. finnally
started voip licencing process. So very soon we will able to make interntional calls at a
very cheap rate. Along with the international call we can think of implemening ip
telephony in various sectors like government, defense, banking, hospitals, ticket
reservation system, educational institutes etc.