September 1999
WHAT IS AN IAD?
Making Sense Of Integrated Access Devices
BY SAB GOSAL
As competition heats up, telecommunications service providers (SPs) are increasingly
pressured to reduce network costs and deliver differentiated, more competitive services.
One of the biggest changes resulting from this challenge is taking place at the customer
premise with a new class of access device. This network element — the Integrated
Access Device (IAD) — combines multiple services onto a single network connection,
allowing SPs to optimize their local loop infrastructures and extend the economicand
management benefits of convergence to the customer. By moving the service demarcation
point into the customer’s network, the IAD distributes the integration function and
enhances network scalability. Customers can buy integrated solutions without the hassle of
managing their own networks; SPs are positioned as partners for providing a wide range of
services. In particular, these new services allow small and medium-sized businesses, often
lacking extensive communications resources, to compete effectively with their larger
counterparts in the global marketplace.
WHAT IS AN INTEGRATED ACCESS DEVICE?
An integrated access device is a compact, scalable access platform that combines
multiple network access functions into a single piece of equipment to achieve lowered
costs and streamlined operations. IADs present SPs with a cost-effective solution to
quickly provision integrated voice, data, and Internet services to all their serving areas
— without having to overhaul (or multiply) their network infrastructures. IADs
process and route multiple types of traffic from customer sites to a wide range of carrier
services, including the PSTN, dedicated transmission services such as fractional T1 (N �
64 kbps), leased lines, and data services such as frame relay and IP. And, as networks
migrate, IADs provide support for new generation services such as voice over packet
(IP/ATM) based services.
An IAD that supports time-division multiplexing (TDM) and voice over packet
technologies gives SPs the best opportunity to broaden their portfolios without
immediately replacing older circuit-switched networks with new packet-based networks.
Instead, SPs can deploy IADs in their existing local loop infrastructures and continue to
serve users with stable TDM-based voice and data services. When the SP is ready, they can
migrate the network to newer services.
IADS FOR THE LOCAL LOOP
Deployed at the customer premise, three fundamental types of IADs exist today:
Basic IAD: Performing the functions of a multiplexer, this
device is deployed in the customer’s existing legacy network and is primarily used to
aggregate voice and data traffic and channelize the traffic onto a single network
connection . For voice services, this device will operate as a channel bank and will
front-end an existing PBX or key system to aggregate voice traffic. A Foreign Exchange
Station (FXS) interface is used to connect to an analog key system, while a Digital System
Cross-Connect (DSX-1) interface is used to connect to a digital PBX. On the data side, the
basic IAD typically provides a serial port (e.g., V.35/X.21) and a fractional Nx64k
interface for connection into the legacy data network, which can consists of routers,
hubs, Frame Relay Access Devices (FRADs), and similar devices.
Enhanced IAD: In addition to functioning as a basic IAD, the
enhanced IAD also features integrated routing, Internet firewalling, FRAD, and DHCP
functionality. With this device, SPs can pursue new market opportunities. For example, for
greenfield business markets, SPs can effectively implement the customer’s voice and
data network based on a single access device. And with those IADs that can support
value-added functions such as local voice switching and localized Centrex services, SPs
can add further value by offering a complete “office-in-a-box” service solution.
Next-Generation IAD: This is effectively an enhanced IAD that
provides the ability to gracefully migrate to voice over packet services. For those SPs
who foresee a migration of their network to a packet-based infrastructure, the
next-generation IAD provides the ideal customer network edge device. One of the biggest
challenges facing SPs in migrating their networks is how to leverage their existing
networks and protect their network investment.
The next-generation IAD addresses these challenges in the local loop. This device can
be deployed seamlessly into the customers existing legacy network, much like the basic or
enhanced IAD, and then offer a migration to packet-based voice and data (IP/ATM) services
via software download. And if the IAD is able to function as a Customer Premise Equipment
(CPE) gateway, it will be responsible for the translation of all legacy voice and data
services to the new class of packet-based services and vice-versa. The end user customer
will therefore retain all legacy network configurations, including telephone numbers.
IADs FOR VALUE-ADDED SERVICES
Offering integrated service bundles allows SPs to create competitive,
differentiated services. For example, a service bundle may include local and long distance
voice and Internet service, packaged with a cost-effective tariff. The ability to provide
further differentiation through service packages with value-added functionality is even
more compelling. Value-added services give SPs an opportunity to gain incremental revenues
without the associated sales or infrastructure costs — in effect, piggybacking
revenues of a bundled service. From an end user perspective, a value-added service can
represent cost savings, high quality of service, and increased productivity.
Given the capabilities of the IAD, the SP can effectively offer a portfolio of
differentiated services, ranging from a voice and data service bundle to a fully managed
family of value-added services. A value-added voice service may include the ability to
deliver local Centrex services, thereby obviating the need for a standalone phone system,
or to dedicate Centrex trunk lines for every phone extension in the customer’s
premise. Similarly, value-added data services may include bundled Internet services with
e-mail, virtual private networking, and even Web-serving support.
However, managing a feature rich value-added service can present operational and
support issues. For example, for a local Centrex service the SP has to manage and operate
all the specific voice features and address end-user service configuration requests that
arise. A solution to this problem is to give end users access to certain IAD features and
functions so that they can manage and custom configure specific service features (e.g.,
turn three-way conference calling on or off). With this flexible management capability in
place, a SP can own and manage the overall service, while minimizing the complexity and
operational overhead of day-to-day end-user configuration requirements.
DISTRIBUTING INTELLIGENCE TO THE NETWORK EDGE
By extending the local loop infrastructure to the customer premise, IADs make it
possible to push much of the service management intelligence from the core of their
networks out to the customer. Localizing service intelligence provides a number of key
benefits:
- Reduced costs through network simplification.
- Increased flexibility in provisioning services and reduced time to market for new
services.
- Increased scalability.
- Increased reliability through distributed intelligence.
To achieve this network model, the IAD must fundamentally support:
- Local service and service management intelligence.
- High reliability.
- Centralized management and control of services from the NOC.
MIGRATION TO A NEW GENERATION NETWORK
With a dynamic market, SPs must pursue new opportunities through higher-value
differentiated services to survive and complete effectively. In telecommunications this
means migration to a more flexible network architecture.
Network migration ideally should occur through software downloads rather than forklift
upgrades, which not only disrupt service, but are also resource intensive. Software-based
migration, managed remotely from the Network Operation Center (NOC), is an essential
factor to complete a graceful network migration on a wide scale. There are three key steps
in developing the local loop infrastructure for a new generation of services:
- Leverage existing infrastructure and protect network investment — select an IAD
that can work in the existing infrastructure to deliver integrated services.
- Protect existing revenue stream and focus on leveraging IAD technology to enhance
revenue stream and build market share.
- Migrate the network to packet-based voice and data services when the SP is ready, and
without having to replace equipment.
CONCLUSION
The ideal IAD is one that can be deployed within the existing infrastructure to
meet both the end user’s and SP’s needs. In its most basic form it should
perform the functions of a multiplexer that integrates the customer’s legacy voice
and data network. It should additionally feature configuration options that allow the IAD
to support integrated routing and value-added services. And, when the SP is ready, it
should also enable a software migration to support packet-based voice and data services.
True IADs represent a new level of freedom for end users and SPs seeking more diverse
services, faster deployment, and more cost-effective maintenance and operation.
Sab Gosal represents VINA Tech-nologies, which develops, manufactures, markets and
services equipment that allows small and medium-sized businesses to connect to high-speed
networks.
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