Voice and Data Integration
Abstract
In the face of increasing globalization and competition,
organizations are seeking to cap their network costs,
while simultaneously focusing efforts on using their
network as a tool to enhance customer service and serve
remote workers. as data becomes a more significant portion
of traffic compared to voice, organizations are exploring
ways to consolidate their voice and data traffic, and
let the voice ride for "free" - a reversal of the TDM
consolidation paradigm of 20 years ago.
This paper explores the following voice and data consolidation
technologies: TDM, Frame Relay, ATM and IP. It examines
the following criteria between these technologies: performance,
efficiency, standards progress, availability of applications,
and availability of services worldwide, and concludes
that IP best meets the needs of organizations. New services
resulting from voice and data integration over IP will
also be introduced.
Executive Summary
Every organization today operates in an information-intensive
environment. The ability to access information, analyze
it, use it for collaboration and distribute it is key
to competitive success. A robust, effective, and economical
network infrastructure for information exchange is critical.
Most organizations currently have multiple network infrastructures
in place. They have invested billions in completely
separate telephone (voice) and data networks. This has
led to a situation with many disadvantages, among them:
- staffing duplication additional
- costs for two physical networks
- lost opportunities to exploit economies of
scale
- inability to take advantage of new applications
- smaller impacts on the bottom line
The challenge for most organizations is providing more
networking services despite flat budgets and no increases
in network personnel. Merging voice and data networks
is a step toward meeting these requirements.
There are many ways to achieve voice and data consolidation.
Voice over IP (VoIP) is emerging as an attractive alternative
to merging voice and data networks that offers unique
capabilities, including: improved economies with both
a local and wide area consolidated network infrastructure,
and new applications that increase productivity and
improve customer service.
Network Consolidation Issues
The networking landscape has changed significantly
in the last few years. Corporations and Service Providers
alike will need to take the following factors into account
when designing next-generation networks that will provide
voice and data consolidation services.
Increasing Globalization. Inter-country market barriers
are dropping throughout the world, and organizations
are taking advantage of this to extend their reach into
the global market. As they do so, their communications
infrastructure must be designed to support their customers,
partners and employees globally.
Increasing Competition. With increased globalization,
businesses are no longer just competing with other businesses
in their local market, but with companies around the
world offering similar products and services. In order
to win business in increasingly competitive environments,
organizations have begun to look for ways to differentiate
themselves. Communications technology has a key role
to play in this differentiation.
Increased Focus on Customer Service. The most effective
way to acquire new customers and retain existing ones
is to deliver high quality customer service. Increasingly,
quality customer service involves timely responses to
requests for information. Organizations are beginning
to translate the need for enhanced customer service
into their IT budget - A recent Yankee Group study of
100 organizations revealed that half of them plan to
spend 20% or more of their Information Technology (IT)
investments on customer focus over the next three years.
New IT investments will be evaluated with this measure:
will this improve our ability to meet the needs of our
customers?
Increasing Mobility/ Remote Users. Sales and Service
personnel are traveling more frequently than ever to
service their customers more effectively. Teleworking
has also gained in popularity due to legislated controls
on vehicle emissions and the globalization of organizations.
These remote workers need access to corporate networks
for information.
Increasing Volume of Data Traffic. Thanks to applications
such as e-mail and the World Wide Web, data traffic
has surpassed the volume of voice traffic in many organizations.
There are many options for consolidating voice and
data networks. Time Division Multiplexing (TDM) has
been the traditional method of merging voice and data
networks over wide area links. Frame Relay, ATM, and
IP are all relatively new methods for achieving voice
and data integration.
Time Division Multiplexing
Deployed in corporate and Service Provider networks
for the past 15 years, Time Division Multiplexing (TDM)
is a mature technology that consolidates voice and data
streams on a shared link. Private TDM networks, as the
first network consolidation technology in corporate
environments, were originally cost-justified based on
replacing expensive public voice networks. The fact
that data could be carried on this network was a bonus
- it essentially rode for "free." Today it is easy to
justify a private network based on the data traffic
carried. The volume of data transmission has been increasing
at a much faster rate than that of voice, and has overtaken
it in many organizations.
TDM transmission slots are assigned either statically,
or statistically. With a static assignment, each voice
or data stream gets a slot at a fixed time, while slots
are assigned on demand in a statistical approach. Equipment
with static assignments are simple and inexpensive,
but waste bandwidth if there is nothing to send at the
given time. Bursty traffic conditions, such as those
experienced in a typical LAN environment, are not handled
effectively. Statistical TDM multiplexors are an improvement
since they deal with bursty traffic by assigning slots
on demand. If one data stream does not need the slot,
another uses it. This is an effective method to deal
with LAN traffic or time-sensitive transmissions such
as voice or video.
Despite the many benefits of TDM, there are some shortcomings
with this technology. TDM technology is proprietary,
so implementing a TDM solution means being locked in
with one vendor. More importantly, TDM only serves to
consolidate data and voice traffic over WAN links; it
does nothing to consolidate the separate voice and data
infrastructures at local sites. Finally, supporting
mobile users is not an option with TDM since multiplexors
do not have the capability to dynamically set up and
tear down links. In a world where more than 50% of workers
change location annually, handling moves and changes
is a challenge. The winning approaches in today's marketplace
will offer solutions for mobility.
Frame Relay
Frame Relay has overtaken X.25 in the North American
market as the packet switching technology of choice.
Today, most Frame Relay circuits in use are used for
LAN interconnect. Voice over Frame Relay is an emerging
technology that efficiently integrates voice and data
transmissions over a Frame Relay network. In May 1997,
the Frame Relay Forum ratified FRF.11, the Voice over
Frame Relay Implementation Agreement, which defines
standards for the transport of voice over a carrier's
public frame relay network and allows vendors to provide
interoperability.
Frame Relay circuits are typically sold as a 64kbps
service with a Committed Information Rate, which guarantees
a minimum bandwidth at the edge of the Frame Relay network.
When used with optimized Virtual Circuits, Frame Relay
offers solid support for time-sensitive voice and data
traffic. As a packet-switched mesh network, Frame Relay
is often cheaper than equivalent leased line, point-to-point
networks, since in Frame Relay you pay by endpoint rather
than by circuit.
Frame Relay has an optional service defined called
Switched Virtual Circuits or SVCs. SVC services support
user mobility; a new destination can be called after
a user moves. The usual burdens of keeping a directory
service must be included since information on changes
must be maintained and distributed electronically.
Frame Relay is one of the more efficient methods of
encapsulating voice into packets for transport - it
has lower overhead that IP or ATM. However, Frame Relay
has some drawbacks for voice and data consolidation
today. Voice encapsulation is newly defined in frame
relay and most implementations do not yet interoperate.
Cost is another concern; adding voice increases the
number of Virtual Circuits users must pay for. Additional
costs may be accrued if an organization wishes to purchase
a Committed Information Rate for voice traffic.
Availability of Frame Relay has improved in the last
few years. Frame Relay is tariffed almost everywhere
in North America and Europe, and availability in Asia
is improving. However, although Frame Relay SVCs are
defined, most service providers do not yet offer SVCs
as a service, or if they do they generally offer them
over leased links only. This factor makes connecting
small offices or home offices today with Frame Relay
cost prohibitive.
Finally, while the Frame Relay Forum has acknowledged
the need for frame relay performance assurances for
delay, delay variance and frame loss for applications
such as voice, specifications for these service levels
have not yet been defined.
ATM
Asynchronous Transfer Mode, or ATM, is a technology
designed in the 1980's for simultaneously delivering
multiple data types such as voice, video and data. ATM
is a proven transport technology that has a high level
of interoperability. ATM has defined Quality of Service
provisions that allow time-sensitive applications such
as voice priority within the network. ATM's high speeds,
efficiency and its explicit design for consolidation
makes ATM an attractive candidate for delivering multimedia
traffic, however there are some factors to consider:
- ATM is optimized for high-speed networks- typically
T3 (45Mbps) or E3 (34Mbps) and higher, although
ATM is defined at T1/E1 speeds.
- ATM is not universally available today- it is neither
tariffed nor available as a special service from telephone
companies in many parts of the world.
For these reasons, ATM is best deployed in backbone
networks where ATM services are available, or private
backbone networks. ATM requires adaptation to lower
speed circuits to serve small branch offices and mobile
users. Increasingly, this will be performed using IP
routers or switches.
IP
IP networks have carried voice and video since the
inception of the Internet as a research environment.
Using IP networks for consolidation offers the following
advantages:
Ubiquity. The growth of the Internet, and especially
the Web, has made IP the world's most popular network
protocol suite. Most PC operating systems now include
an IP stack. This has led to the development of a plethora
of exciting new computer applications developed to run
over IP. This in turn reinforces the "everything over
IP" phenomenon.
Truly Standard. IP is the best open standard in the
market. Customers can buy products from a multitude
of vendors with high expectations they will interoperate.
There is a large, worldwide organization, the Internet
Engineering Task Force, or IETF, with representation
from the majority of networking vendors, whose sole
function is to develop standards for the Internet.
Transport Independent. IP, being a network layer protocol,
can be delivered on any type of transport media - LAN,
dial-up modem or ISDN connection, cellular or wireless,
Frame Relay or ATM. This is most advantageous for mobile
users, telecommuters, and organizations with branch
offices in countries still developing a data communications
infrastructure. Unlike other technologies such as Frame
Relay, IP is the only technology that allows for full
network consolidation in both the local and wide area.
These factors make IP the first choice for voice and
data network consolidation. However there are still
some hurdles to overcome. Standards for multimedia consolidation
are new; so many vendors have not yet implemented the
standards. For those that have, interoperability is
in its infancy. H.323 is a suite of standards defined
by the International Telecommunications Union (ITU)
to support multimedia communication over LANs. Although
interoperability demonstrations have already taken place,
full interoperability is not expected until mid-1998.
Defining and implementing Quality of Service Guarantees
in IP networks is another issue that the ITU and the
IETF are working on. IP, as a connectionless protocol,
is not a technology that was initially designed for
quality of service. However, new standards such as RSVP,
802.1q and MPOA are attempting to address this shortcoming,
either in various transport environments or native to
IP. In the meantime, voice over IP vendors have engineered
their solutions to work around variances in delay, throughput
and packet loss to deliver good quality voice solutions
even over the Internet. The effects of jitter are minimized
through the use of jitter buffers. Voice reconstruction
allows many VoIP solutions to tolerate packet losses
of 15-20% or more. In a corporate IP network, where
the above variables can be more easily controlled, the
voice quality is excellent.
Network Consolidation Applications and Services
Consolidation of voice and data in an IP network allows
the following new applications to be implemented that
improve communication, thereby improving customer service
and increasing the efficiency of an organization.
Remote Collaboration/Virtual Meetings
As more people work from home or from temporary locations
while traveling, the need for distributed communications
becomes more and more important to the effectiveness
of employees and the overall efficiency of the organization.
Network consolidation via IP allows for applications
such as data collaboration, voice conferencing and videoconferencing
using standard equipment such as laptops and dial-up
modems. Remotely located users can participate in meetings
and discussions and have as much information at their
disposal as employees located at head office. At the
same time, costly long distance telephone calls from
places such as hotel rooms are eliminated.
Web-based Computer Telephony Integration
Computer Telephony Integration combines computer and
telephone technology for special applications. Many
organizations view CTI as part of their strategic business
process for serving customers. Traditional CTI is an
interface between the PBX of the voice network and the
data network switch. They are not actually consolidated,
but operate in parallel.
CTI is most frequently used in environments where repositories
of information, such as databases, must be accessed
with each incoming call. The person responding to the
incoming telephone call has additional information,
such as the customer's previous buying history, preferences,
or geographic location. In other cases, the caller may
be accessing a FAX-on-Demand system or requesting account
information. Computer Telephony Integration responds
to the tones of a telephone or a single voice command
such as a number.
CTI technology is most applicable in environments such
as customer service centers and banking. It is designed
to increase customer service by giving callers immediate
access to data specific to their needs. IP adds value
to CTI technologies by enabling Web-centered applications
for customers, improving customer service and potentially
improving sales. People browsing an organization's web
site can "click" to talk to a sales or service representative,
while keeping their web session active. Further, sales
representatives have the opportunity of seeing what
the customer sees on a their web site, and can even
"push" more relevant information to them.
Voice and Fax Toll By-Pass
VoIP (Voice over IP) can use the Internet, or company
intranets, as an alternative, economical means of long
distance voice or fax communication. A VoIP or IP telephony
gateway converts circuit-switched voice or fax traffic
to packet switched data that traverses an IP network.
This can offer significant savings over a traditional
long distance telephone call, since Internet billing
is typically access-based and not usage-based. In the
case of company intranets, payback periods can typically
be measured in months.
Summary
Voice over IP is emerging as a key technology for network
consolidation. Users can take advantage of the growing
momentum of the Internet and private IP networks to
get economical bandwidth and leverage an established,
ubiquitous infrastructure. All other alternatives, while
having their place in IP networks, do not offer the
range of advantages that Voice over IP will be delivering.
At the same time, simply sharing facilities for voice
and data limits the leverage that an organization can
gain. True integration of voice and data services increases
productivity and overall effectiveness, while the development
of innovative applications integrating voice, data,
and multimedia will create demands for new services.
The combination of voice and data consolidation with
a set of value-added services that improve company efficiency
while reducing costs is a winning proposition for hard-pressed
organizations that need to contain networking costs
while increasing competitiveness.
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