The Internetthe technology behind the accessby Roderick Campbell NLnet was founded in 1990 as one of the 10 provincial regional Internet service providers that comprise CA*net. The CA*net is a Canada-wide TCP/IP backbone network with three 2 x T1 (2 x 1.544 Megabits per second-Mbps) links that provide access to the Int ernet throughout the world. The NLnet originally consisted of six institutional members: Memorial University, Cabot Institute (now Cabot College), the Federal Department of Fisheries and Oceans, the Institute for Marine Dynamics, the Marine Institute (now Fisheries and Marine Institute of Memorial University) and the Federal Department of Forestry. All of these sites are located in St. John's. NLnet has grown and presently has over 20 institutional and commercial members with points of presence (POP) in C orner Brook, Clarenville, Gander, Grand Falls-Windsor, Stephenville, Burin and Labrador City. Carbonear, Lewisporte, Port aux Basques and Happy Valley-Goose Bay will have operational POPs by mid May, 1995. At all POPs, NLnet provides public Internet access modem pools, local area network (LAN) connectivity, as well as modem pools dedicated for use by STEM~Net clients. NLnet operates as a not-for-profit cooperativ e and is dedicated to providing an open and ubiquitous network within the province. The links off the island are a T1 to the CA*net regional NSTN in Halifax, and T1 to CA*net regional PEInet in Charlottetown. The links within St. John's are typically leased (dedicated) 56 kilobit per second (Kbps) lines with NLnet routers at member sites . The cross-island links were recently changed from leased 56 Kbps services to a fully meshed 56/64 Kbps Frame Relay network. This provides a more reliable and flexible network while lowering line costs. The line to Labrador City is a 19.2 Kbps link to th e NLnet site in Corner Brook. There are plans to add more POPs by the third quarter of 1995.
As an example of how the provincial Internet functions, we can examine some network activity involved in a call by a user of STEM~Net services in Labrador City. A local phone call is made with a modem to the Labrador City STEM~Net modem pool at 944-3677.
Once connected to Calvin, a common Internet activity is downloading files from a remote location using the file transfer protocol (ftp). One of the world's most popular sites is ftp.cica.indiana.edu which is home to a large Microsoft Windows software arch ive along with other information. If a trace is made between the main NLnet router in St. John's and the site above, a typical route is through three CA*net regional routers along T1 leased lines, through a 2 x T1 link to a node in New York state. From th e router in New York it may pass through 10 other routers, typically via T3 links, before it reaches Indiana, and is passed via LAN to node ftp.cica.indiana.edu. All the information used in the Calvin ftp session passes along a route similar to that above . In all, the interactive traffic in this one session will involve roughly 20 routers and links. Currently, most end users do not pay to access the Internet but using this technology does carry a financial cost. The Internet has been built on the model of flat subscription fees for a connection of specific bandwidth. Host institutions typically pay s ubscription fees to cover these fixed costs for Internet provision. Once this capacity is obtained, the incremental costs of providing access to this bandwidth is near zero. Often the user of these services sees the costs as essentially free. The NLnet bu dget is approximately $500,000/year with each new POP costing about $35,000 for capital costs and the first year of operation. New technologies are being explored in order to provide more reliable and cost-effective services. Frame relays links are one op tion. Each frame relay link costs over $500/month plus a traffic charge and these costs are considerably less than standard leased digital 56 Kbps links. If the ftp session to ftp.cica.indiana.edu is examined without the use of the NLnet/Internet fabric, considerable costs become evident. A long distance call from Labrador City to Indiana to retrieve a 300 kb file at 9600 bps could take well over five minu tes. It could be worse--the archive might be in Australia. Fortunately for the user, access is not complicated at all. The connecting process goes on behind the communications software that is loaded into the PC. Programs like NetScape and Mosaic simplify the process by giving users a graphical interface. The tec hnology that allows us to communicate in this manner is a tremendous breakthrough in communications and is providing us with a new, efficient, fast and very effective method of sharing information. Definitions
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This pool is controlled by a specialized device called a Terminal Server which allows serial devices (modems) to interface with a network. This Terminal Server is part of a small LAN which has a router. A router is a device that connects different network
s by directing (routing) packets of information between them, and exchanges this information with other routers using specialized protocols. Routers are "intelligent" and can automatically route around failed or inefficient network links when there are al
ternative or better routes available. Two of the networks that the Labrador City
router connects are the small LAN with the Terminal Server, and the network consisting of the link to Corner Brook. Since the STEM~Net modem pools are dedicated to the STEM~Net unix server, Calvin, located at Memorial University's St. John's campus, the r
outer in Labrador City directs this traffic through its link to the Corner Brook router where it is sent via the Frame Relay network to the main NLnet router in St. John's. This traffic is then sent via Memorial's LAN to Calvin. All information sent from
the STEM~Net user's modem passes through at least three routers, over two LANs and two wide area network (WAN) links before it reaches Calvin. This is quite often only the first few steps before typical Internet activity takes place.