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GC 2000 Team
WAN Cabling and Network Architecture.
The Community-wide backbone consists of a Continental Cablevision, Inc. (CCI) constructed and managed lightwave Wide Area Network built in a star topology. It will be utilized as a trunking network between the District's ten attendance center LAN's located on eight campuses, the District's Central Office LAN and each of the community partner LAN's including: Pekin Community High School, the City of Pekin, Daily Times, Dirksen Congressional Leadership Research Center, Pekin Hospital, and Pekin Library, in addition to the head-end of Continental Cablevision (providing the gateway to the subscriber network and area school districts).
The lightwave system consists of dedicated pairs of single mode fiber optic cable deployed between the LEA's hub--located in the District's Teacher Center--and each individual attendance center's Library Media Center (LMC) and community resource centers data processing rooms. The cable is "overlashed" to the existing CCI CATV distribution system in Pekin, creating a "dark fiber" network in support of the district schools and community partners. One hundred eight miles of glass fibers have been installed.
Attenuation specifications for the fiber optic cable have been set at .35dB/km at 1310 nm and .25dB/km at 1550 nm. This fiber specification will allow for future use of Wave Division Multiplexing on a single fiber as well as transmission at both specified wave lengths--effectively doubling the capacity of the network. This will permit low cost growth and represents one of several justifications for the use and funding of this technology.
Transmission Standard.
The ATM-Forum compliant Asynchronous Transfer Mode or ATM technology will be utilized along the WAN. This international standard for "cell relay" high speed cell switching provides the scaleable speeds, reservation and management of bandwidth necessary to integrate voice, video and data. Allocation of bandwidth to meet the "real time" delivery demands of voice and video is but one reason to use and fund ATM technology. As such, this technology allows for the optimal utilization of the lightwave technology making up the backbone of this network.
Communications Devices.
The ATM backbone of the WAN is characterized by a central IBM 8260 Multi-port Intelligent Switching HUB and seven remote IBM 8260's each with up to five IBM 8285 ATM workgroup switch closets transferring voice, video and data bits at speeds of 155Mbs and supporting anywhere from twelve 25Mbs workstation connections to hundreds of 25Mbs workstation connections utilizing IBM 8285 workgroup expansion chassis. Planned for implementation by the end of the third quarter 1997 is the integration of a central HUB PBX and seven remote HUB key system units piggy-backing across the ATM WAN utilizing IBM ATM-circuit emulation technology.
The HUB provides the routing and switching functions necessary for the interconnection of the home, district, school and world. The IBM ATM Campus Manager supports the ATM Management and Network Management programs necessary to the operation of the WAN and WAN/LAN (as more fully discussed below).
Networking Management.
The ATM Management Program, an IBM AIX/UNIX system software program running on an IBM RS/6000 or RISC platform, provides topology display, resource configuration, statistics display, and other user-friendly, graphically displayed functions necessary to the management of the WAN and LAN's. The Network Management program, also an IBM AIX/UNIX application software program running on the above same RISC platform, provides network monitoring, problem diagnosis, error recovery, performance management, and other tools to simplify control of both the LAN and WAN networks.
Building Cabling.
All LANs will be constructed of Sprint supplied and installed CAT-5 wiring. At each of the eight campuses will be found, generally, in the learning center a WAN HUB closet containing an IBM 8260 intelligent switching HUB and . Within each of the 10 attendance centers will be found a "star-wired" 25Mbs ATM topology supporting, generally, five student and one teacher workstation. In addition, several buildings have integrated along the ATM backbone their existing 16Mb token-ring and/or 10-base-T ethernet labs, each connected to an IBM 8271 ATM bridge located in the HUB closet of the LMC.
Within the central HUB location in the Washington School Teacher Center will be found a similar topology connecting each administrative, instructional, and support work area. In addition, however, will be found the District-wide administrative management system--consisting of an IBM AS/400 mid-range computer or enterprise server containing resident student, financial and employee applications. Instructional and administrative applications, including IBM's School Vista classroom management software and instructional courseware are "served up" on one of four centrally located IBM PC720 file servers. IBM RS/6000 servers provide Internet mail, news and WEB support in addition to centralized network management and monitoring support. (Firewall, Internet access and terminal server hardware and software detail have deliberately not been provided for security reasons.)
All LAN's will be constructed of Category-5 unshielded twisted pair cabling configured in a star topology with a run length no greater than 130 meters from one or more (depending upon building size) wiring closets. (Wiring closets will be connected to each buildings HUB via multi-mode fiber.) Attenuation specifications for the unshielded twisted pair cable have been set at less than 21 dB/km at MHz to 220 dB/km at 100 MHz. Media filters have been specified to guarantee emission levels which meet FCC regulations. The cable utilized is designed to support analog frequencies to 100 MHz for data transmission of up to 155 Mbs today with potential up to 622Mbs near term. This will accommodate the transmission speeds anticipated from student and teacher workstation and their voice, video and data requirements well into the future--a reason to support the use of this technology.
Transmission Standard.
The Asynchronous Transfer Mode (ATM) protocol was chosen as it allows for the high speed cell switching which enables scaleable speeds, reservation and management of bandwidth necessary to integrate high bandwidth applications including voice, video and data along a single network. It allows for the emulation of token-ring and ethernet LANs and the transmission of TCP/IP and other traffic. Its superiority to token-ring and ethernet environments includes, in addition to that already noted, full duplex capabilities, secure transmissions, and superior error recovery. Translated, each user has a dedicated, secure, two-way, non-degraded, full 25Mbs stream of voice, video, and/or data.
In addition, the ATM protocol provides for greater copper wire cabling ranges (130 meters CAT-5 UTP and 300 meters CAT-5 STP vs. 100 meters for Token-ring and Ethernet). It is inherently superior as respects network management capabilities and assistance in finding problems, correcting problems and, generally, optimizing performance.
Operating Systems and Hardware.
The network utilizes Novel Netware 4.1 as its network operating system. IBM's School Vista running on Windows95 will provide a menu-driven interface to the network for the teachers and students. All will run on a Pentium-based, IBM PC720 file server. ATM network, management, and control functions are AIX/UNIX based software running on a single IBM RS/6000 platform.
Connection to the Internet
Cabling and Network Architecture.
The District's Internet access is made up of two separate connections: a terminal server connection and an ISP connection. Each interfaces with the other through the central ATM switch. The terminal server component provides the gateway to the Internet for the district and is positioned to serve all Tazewell County ROE schools with either direct or dial-up access. The Terminal Server permits staff and community dial-up access from home on the unsecured side of the firewall and appropriate enterprise and Internet access from the secure side of the network. The leased-line T1 connection was chosen as it provides the speed and bandwidth necessary to support the numerous ATM direct, planned cable modem direct, and current terminal server dial-access users.
Dial Support.
Configured to the central office LAN of the District are two terminal servers each with eight 28.8 Kbs modems. These devices provide the gateway to the Internet for the non-CATV school districts and community of life-long learners. Future plans (2nd quarter 1997) call for the deployment of cable modems achieving initial access rates of 1.45Mbs.