T carriers, e.g., T1 and T3, are digital, leased twisted-pair lines, designed to carry voice (via Pulse Code Modulation (PCM)) and data communications up to distances of 48miles/80km. Approximate available bandwidth for a T1 is 1.5Mbps, and for a T3, 45Mbps of available bandwidth. T1s provide 24 64Kbps channels and a T3, made up of 28 T1s, can provide 672 64Kbps channels for use. These channels can also be bonded together in multiples of 64Kbps (T1 carrier) or 1.5Mbps (T3 carrier). T carriers are used as dedicated facilities between customer premises and Local Exchange Carriers (LECs) and InterExchange Carriers (IXCs) providing a dedicated communications path for LEC/IXC-based voice and WAN services.
T carriers can also be used as private (leased) line circuits between two customer premises. T1/T3s could be used by NHS to provide reliable, landline-based communications between the rural office locations and a central hub, in turn providing dedicated connectivity to the New York City location. T1/T3s do need to account for cost considerations as IXCs often charge customers based on distance between the customer premises and do rely on dedicated telecommunications infrastructure being in place for service use.
Castelli, M. (2003). Network Sales and Services Handbook. Indianapolis : Cisco Press. Cable Modem network access are two alternative ways to connect to a network service provider without using a more expensive dedicated service, e.g. T1/T3. Cable Modem networks achieve the same result of providing dedicated access to network service provider, such as an ISP (Internet Service Provider).
Cable Modem networks use coaxial cable/fiber optic connections, providing broadband network access to customer premises/end-users. This broadband access is based off IEEE 802.3 (Ethernet) standards and can provide network speeds up to 300Mbps. A cable modem-based approach could be used by NHS in providing broadband network speeds to all locations as it is a given here all locations are served by a local cable television (CATV) provider. It is presumed these CATV providers also offer an Internet package which, when coupled with an appropriate virtual private network (VPN) implementation, could provide NHS reliable and secure connectivity between all offices and the New York hospital.
Elnashar, A., El-saidny, M. A., & Sherif, M. R. (2014). Design, Deployment and Performance of 4G-LTE Networks: A Practical Approach. Chichester, West Sussex, United Kingdom: John Wiley & Songs. Cellular-based networks are deployed worldwide providing users with reliable over-theair voice and data communications services, via different bands in the radio frequency spectrum. Common networks, such as 3G, 4G-LTE, GSM, are often operated and maintained by larger cellular carriers, such as Verizon Wireless, T-Mobile, or AT&T. Other carrier providers exist but often are small area resellers providing backhaul connectivity to these larger carriers.
Cellular-based network connectivity is often used for mobile voice and data communications implementations, due in large part to the low-power transceivers used by cellular communication devices and widespread manufacturing and use in mobile devices.
Given the rural office locations, a cellular-based approach could be used by NHS, however concerns regarding the data and connectivity requirements could limit the viability of this approach. Evans, B. G. (1999). Satellite Communications Systems, 3rd Edition. London, United Kingdom: Institution of Electrical Engineers. Satellite communications systems are available in one of three configurations: fixed satellite service (FSS); broadcast satellite service (BSS); and mobile satellite service (MSS). Satellite-based systems are used to provide several services: mobile and personal communication systems, multimedia systems, military business and small satellites, and global positioning/navigation.
Satellite-based communications systems use ground terminals to send/receive signals to/from synchronous Earth-orbiting satellites. These satellites cover a portion of the Earth in an area referred to as the satellite “footprint.”
Similar to a cellular-based approach for NHS, satellite connectivity can be considered an option for rural office connectivity, however concerns associated with solar flares and atmospheric ionization (both can affect satellite signal reliability and stability). Fitzgerald, J., Dennis, A., & Durcikova, A. (2012). Business Data Communications and Networking, Eleventh Edition. Hoboken: John Wiley & Sons.
T carrier circuits are the most common form of dedicated-circuit services in North America today; the European standard is based on the E carrier. The T carrier is a dedicated-circuit service which is leased from a Local Exchange Carrier, providing connectivity between intra-city customer premises or from a customer premise and an InterExchange Carrier for long-haul leased line services.
T carriers, as dedicated facilities, provide a dedicated communications path for LEC/IXC-based voice and WAN services and can also be used as private (leased) line circuits between two customer premises.
T1/T3s could be used by NHS to provide reliable, landline-based communications between the rural office locations and a central hub, in turn providing dedicated connectivity to the New York City location. An IXC would be required to provide the long-haul dedicated services between NHS office(s) and the New York area. Golden, P., Dedieu, H., & Jacobsen, K. S. (2008). Implementation and Applications of DSL Technology. Boca Raton, FL: Auerbach Publications.
DSL access network customers are Internet service providers (ISPs), application service providers (ASPs), and other network operators together with the end users. DSL services are available in various configurations based upon the premise distance from the serving telecommunications central office.
xDSL service is best suited for native IP traffic, but xDSL implementations can also be configured to support native voice or voice-over-data configurations. These implementations are based on the use of Plain Old Telephone Service (POTS) splitters or voice-over-data Pulse Code Modulation (PCM) equipment, such as telephone Private Branch Exchanges (PBXs) with DSL adapter cards.
xDSL is a viable option for NHS and the rural office locations, however a consideration needs to be made regarding the ~18,000-feet theoretical limit between the customer premise and the serving central office. Because DSL services are analog-based services, the DSL signal weakens over distance which in turn affects the amount of bandwidth available to the customer/end-user.
Horak, R. (2007). Telecommunications and Data Communications Handbook. Hoboken: John Wiley & Sons, Inc. Access technologies are critical, regardless of the medium, to connect premises to the serving network. xDSL services are one such available technology and are available in various configurations (IDSL, ADSL, SDSL, HDSL, VDSL) based upon the premise distance from the serving telecommunications central office. Asymmetric Digital Subscriber Line (ADSL) provides an asymmetric connection between customers and network providers, such as Internet Service Providers (ISPs). ADSL is asymmetric in nature because the downstream signal (ISP to customer) is stronger than the upstream signal (customer to ISP), in turn resulting in faster downstream speeds than upstream.
ADSL is a viable option for NHS and the rural office locations, however a consideration needs to be made regarding the ~18,000-foot theoretical limit
between the customer premise and the serving central office. If rural office locations exceed this 18,000-feet limit, the only viable xDSL option is IDSL with 144kbps available for upstream and downstream connectivity.
Janevski, T. (2014). NGN Architectures, Protocols and Services. Chichester, West Sussex, United Kingdom: John Wiley & Sons. Cable television (CATV) providers have the necessary infrastructure in place to provide fixed broadband Internet service to a broad range of urban and rural customers. Cable modem service uses the Data Over Cable Service Interface Specification (DOCSIS) standard in enabling high-bandwidth data services across existing CATV infrastructure. Cable modem-based services are used to provide broadband data services, in some cases 100Mbps or higher, to CATV-wired premises, using the DOCSIS standard protocol and interface suite.
Cable modem-based services are a viable and considered option for NHS, leveraging the existing CATV service at each rural location. This high-speed Internet access is capable of support NHS’s requirements for long-haul connectivity back to New York without suffering from distance (DSL), propagation (satellite), or signal coverage (cellular) issues.
Sun, Z. (2014). Satellite Networking: Principles and Protocols, Second Edition. Chichester, West Sussex, United Kingdom: John Wiley & Sons. Satellites, placed in geosynchronous orbits (covering the same Earth footprint from a fixed location in space), are used for networking. This geosynchronous orbit – about 22,000 miles above the Earth – enables these satellites to provide continual network coverage and be an active part in the larger global network infrastructure. These satellites, from an altitude just over 22,000 miles, provide communications coverage over a fixed geographic area called the “footprint.” Communications are sent to the satellite from within this footprint for subsequent retransmission to another location within the same footprint, such as an Earth station for subsequent voice/data communications.
Satellite-based communications services is a viable option for NHS, however, for the bandwidth necessary to support the given 100 MB file transfers,
satellite is not the best medium to use here. Satellite is better suited for short bursts or steady-stream comparative low-bandwidth requirements rather than the near/real-time high-bandwidth requirements of NHS.
Trestian, R., & Muntean, G.-M. (2004). Convergence of Broadband, Broadcast, and Cellular Network Technologies. Hershey: Information Science Reference (an imprint of IGI Global). Internet connectivity can be accomplished via one (or more) of these technologies, with the determining factors being user location and required bandwidth: Global System for Mobile Communications (GSM), Enhanced Data Rates for GSM Evolution (EDGE), Universal Mobile Telecommunications System (UMTS), High Speed Packet Access (HSPA), Long-Term Evolution (LTE), Worldwide Interoperability for Microwave Access (WiMAX), Wireless Local Area Networks (WLAN), or Wireless Personal Area Network (WPAN).
Regardless of the specific implementation (GSM, EDGE, etc.), over-the-air network connectivity is often used for mobile voice and data communications implementations, due in large part to the low-power transceivers used by cellular communication devices and widespread manufacturing and use in mobile devices.
Given the rural office locations, this over-the-air approach could be used by NHS, however data and connectivity requirements could limit the viability of this approach.
Given NHS’s requirements as stated and provided, the recommendation here is a cable modem-based Internet access solution. This solution leverages the fact all NHS rural locations are currently serviced by a local cable television (CATV) provider, and it can be presumed this (or these) CATV provider(s) can support DOCSIS-based Internet services. While it is provided in this case NHS has faced increasing difficulty in procuring high-speed Internet services, the nature of these challenges are not provided. If it is determined cable-based services are not viable, a backup consideration here
is dedicated leased line, which would be negotiated and procured via a serving Internet Service Provider (ISP).
A cable-based Internet access solution is immune to weather conditions, such as heavy rain or snow, and solar flares that can affect radio frequency (RF)-based communications, such as cellular, microwave, and satellite communication systems. Furthermore, this solution can support the NHS requirement for 100 MB file transfer rapid transmission – a conservative estimate of a 10Mbps service can transmit this file in approximately 1-1/2 minutes. (Note: This is a conservative estimate and does not account for file/transmission protocol or IP Security, such as Virtual Private Networking (VPN) overhead or actual available bandwidth at time of transmission).
Regardless of the transmission medium adopter in this solution – CATV or dedicated leased-line – the Internet security and encrypted connection can be implemented using one of several VPN hardware or software mechanisms, with encryption strengths (e.g., 128-/256-bit) determined upon separate requirements analysis.
Accounting for the fact NHS is operating and maintaining state-of-the-art health services in rural locations, it can be ascertained NHS can be considered an early majority organization, possibly with early adopter tendencies. It could be aggressive to consider NHS an early adopter based on the information and background provided here, however based in the NHS already pursuing high-speed Internet services, this is a supportable position. In considering the technology adoption S-curve, NHS falls on the far-end of this curve in the Internalization stage, based on the investment in state-of-the-art systems to date, and it is for this reason this proposed solution will likely be adopted by NHS management.