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Prince Rupert Broadband Network Plan
Prince Rupert is a city of approximately 17,000 residents located on an island just off the coast of British Columbia, near the Queen Charlotte Islands. Boasting one of the largest natural harbours in the world, its economy has been traditionally dependent on natural resources such as fish and forest products. However, faced with declining trends in these economic sectors in recent years, the city has recognized the need to diversify its economy into other knowledge-based industries, and to improve the profile of its existing industries to the outside world in order to remain competitive in the global marketplace.
A high-speed telecommunications infrastructure was seen as a key enabler to stimulate economic growth in Prince Rupert, as it would allow local businesses to communicate and collaborate more effectively, and create an environment for new information-based businesses to deliver services. Furthermore, the ability to offer broadband connectivity throughout the community and to the outside world could provide an attractive incentive for outside businesses to locate in Prince Rupert.
CityTel, the local municipally-owned telephone company, spearheaded a project in late1996 to lay the groundwork for such an infrastructure. Coined the Broadband Initiative, the project began with a design for a city-wide fiber-optic backbone to position CityTel for enhanced delivery of voice and data services, which would bring fiber-optic cable within 500 metres of any location in Prince Rupert. This backbone was completed in late 1997.
The initiative grew to include a business development analysis, market analysis and environmental assessment, which indicated that the demographics, interest-level of the population, and level of computer penetration in Prince Rupert were ideal for deploying broadband services. This led to the development of this deliverable, the Broadband Network Plan, to provide CityTel with a technical and operational blueprint for a broadband city-wide network. The Broadband Network Plan was conducted in parallel with a program of ADSL technology trials to determine the viability of delivering high-speed services over the existing copper plant, and a Marketing Analysis to assess revenue potential and provide marketing strategies for value-added broadband services. It also provided budgetary costs as an input to a Financial Analysis, to determine the sensitivities of deploying the network from an economic perspective.
The approach taken for designing Prince Rupert's network was unique, as Prince Rupert's future applications for the network are difficult or impossible to predict. A purely application-driven approach was deemed unrealistic due to a lack quantifiable market demand for applications, a "build it and they will come" approach was considered to be too risky from a business and technological perspective, and a "just in time" approach was viewed as restricting CityTel's ability to respond quickly to changing market demands. The final decision was to combine the three approaches, resulting in an Initial Deployment which will be as low-cost and as low-risk as possible, yet will be scalable in the short term and upgradable as the network capacity is approached.
The following statement describes the desired role of the network in enabling CityTel and the community to achieve its objectives:
"CityTel will be a recognized leader in generating economic growth and community pride, through the use of an ubiquitous, cost-effective, broadband network infrastructure to enable the delivery of value-added services to the community."
In order to fulfill this role, the network will need to be ubiquitous, market-driven, cost-effective, constructed using proven technologies supported by well-defined industry standards, economically scalable, secure and reliable. These essential characteristics are the basis against which to evaluate potential network designs.
Design Alternatives Considered
Three design alternatives were considered for the Prince Rupert
Broadband Network: a solution based purely on frame-switching
technology, a solution based entirely on cell-switching (ATM)
technology, and a solution which combined a cell-switching core
with frame-based edge devices. Based on a detailed evaluation
of the alternatives against the required characteristics of the
network, a purely frame-based solution was chosen primarily because
it provided the lowest initial investment cost and technological
risk yet supported the delivery of a wide range of value-added
services including high-speed Internet access, IP-based video
conferencing, groupware and video on demand. The only limitation
of a frame-based solution is its inability to provide very high-quality,
two-way video, which is not anticipated to be required until one
to two years in the future when there will be applications available
to support it.
The initial deployment of the network consists of five subsystems, which are based on frame-switching technology:
- The Core Routing and Switching Subsystem, which handles the transfer
of all network traffic between customers;
- The Fiber Subsystem, which provides high-speed network access
to customers with bandwidth requirements of 10 Mbps or more;
- The ADSL Subsystem, which uses CityTel's existing copper plant
to connect residences and small businesses to the network;
- The Gateway Subsystem, which includes all connections to external
networks, such as the Internet or the Public Switched Telephone
Network; and
- The Server Subsystem, which provides all network services and applications that reside on top of the basic infrastructure.
The network infrastructure outlined in the Broadband Network Plan
ideally positions CityTel to provide leading-edge telecommunications
services today with minimum risk and maximum functionality, yet
provides the flexibility to take advantage of even higher speed
technologies tomorrow in response to market demands.To ensure
the success of the initiative from an economic perspective we
need to market the service to business and residences. This effort
is required both internally to create awareness within Prince
Rupert of the capabilities of the network and the value-added
services that can be delivered over it, and externally to promote
the unique advantages Prince Rupert has to offer as a "completely
wired city" in the eyes of organizations looking for a cost-effective
alternative to high-cost urban centres.
The purpose of this section is to describe the physical network infrastructure for the Broadband Network, which consists of the various physical media over which traffic is transmitted and received.
The components of the physical infrastructure and the proposed technologies to support them are listed below:
High-speed customers will connect to the Broadband Network at either 10 or 100 megabits per second. These customers will receive a fiber transceiver, which will provide a single Ethernet or Fast Ethernet port on their premises. The back of the transceiver will connect to a single run of single-mode fiber-optic cable that feeds directly back to the central office.
Residential customers will receive an Asymmetrical Digital Subscriber Line (ADSL) modem as part of their monthly charge. A single Ethernet port will be provided on the ADSL modem for the customer's use, which could in turn be connected to a single computer or a group of computers. The modem will use existing copper wire of CityTel's external cable plant to connect back to the central office.
All backbone equipment separated by more than 200 metres will connect using single-mode fiber-optic cable.
Prince Rupert has nearly 6,000 residences and 1,000 businesses that currently have at least one telephone line each. This existing copper plant will be utilized in the Broadband Network to provide high-speed data services to customers throughout the city using a technology called Asymmetrical Digital Subscriber Line (ADSL). There are various flavors of ADSL technology, and, after assessing the trends in the ADSL industry, the "rate adaptive carrierless amplitude phase modulation" version has been chosen as most suitable for Initial Deployment of the Broadband Network.
The incoming lines from customer sites are split off into two lines upon entering the Central Office, with one of these lines going to CityTel's central telephone switch (to accommodate standard telephone calls coming over the same line), and the other line feeding into the central office component of the ADSL subsystem. This central office component has been designed to support up to 1,400 customers and will be connected directly to the Core Routing and Switching subsystem. Each of these customers will require an ADSL modem at the customer premises.
CityTel's demarcation point for ADSL service will be the ADSL
modem provided to the customer as part of the monthly charge.
A single Ethernet port will be provided on the ADSL modem for
the customer's use; a single computer or a group of computers
could be connected to the ADSL modem.
See also: ADSL FAQ
Some customers using the Broadband Network will require higher
data speeds than can be provided by the ADSL subsystem. In particular,
larger businesses, schools, institutions and providers of high
bandwidth services will require high upstream data speeds. The
initial deployment of the network has been provisioned to support
sixty of these users at speeds of 10 or 100 megabits per second.
Fiber customers will receive a fiber transceiver, which will provide a single Ethernet or Fast Ethernet port for high-speed connection into the network core.
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