The Greek School Network - Structure, Design Principles, and Services Offered

The Greek School Network (GSN) is a closed educational network that offers advanced telematic and networking services to all units of primary and secondary education schools and administration offices in Greece. The main objective of GSN is the implementation of a network infrastructure for the interconnection of the school laboratories and the provision of a wide range of network and telematic services to students and teachers. The GSN separates its telematic services to two major groups: the centralized services and the end-user services. The purpose of this paper is to describe the GSN structure, the services it provides, and its design and operational principles. INTRODUCTION: THE GREEK SCHOOL NETWORK The Greek School Network – GSN (Greek School Network, 1998), described in this report, is the educational intranet of the Ministry of Education and Religious Affairs, which interlinks all Greek schools and educational administration offices, and provides basic and advanced telematic services to students, teachers, and administration personnel. It also contributes to the creation of new educational communities that use Informatics and Communication Technologies in the educational procedure. The telematic services of the GSN are based on Open Source technologies that are modified in their source to fit exactly the needs of the Greek educational community. The GSN offers a large number of services to more than 15.000 schools and administrative units, and over 50.000 teachers in Greece, across all the 51 prefectures of Greece. The services are offered over the network that GSN has developed and maintained since 1998. The network is hierarchically structured into three layers in order to manage the complexity that comes with the large number of sites that are covered: • Core Network: The Greek Schools Network interconnects with the Greek Research and Technology Network (GRNET, 1995) in seven main points, using it as its core network. • Distribution Network: The distribution network provides for the interconnection of the schools and educational administrative units to the core network, and consists of 51 nodes. The GSN has installed in the capital of each prefecture, network and computational equipment, to ensure optimal access of the prefecture‘s schools to the network and its services, and is further separated into two distinct layers: • Access network: It is used to directly and efficiently interconnect the schools to the prefecture‘s access point. The telecommunication junctions used to interconnect each school are selected on the basis of financial and technical criteria from an array of available options: Digital ISDN circuit (bandwidth: 64 128 kbps), Analog leased line (0,128 – 2 Mbps), Wireless link (10 Mbps), ADSL circuit (384/128 Kbps, 512/128 Kbps, 1024/256 Kbps), VDSL