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The Internet is a global collection of networks of varying sizes. ... Internet, however international organizations such as The Internet Society & The American Registry of ...
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Slide 1:Accessing The Internet
Garfield Bolt
ISP Manager
Anbell Telecom
Slide 2:What is the Internet The Internet is a global collection of networks of varying sizes.
These networks are connected in various ways, to form what we now know as the Internet in fact the name is derived from the two words, interconnect & network.
Slide 3:Origins of the Internet Since its beginning in 1969, the internet has grown the Internet has grown from four host computer systems to tens of millions.
Nobody really own the Internet, however international organizations such as The Internet Society & The American Registry of Internet Numbers (ARIN) are responsible for overseeing the formation of the policies and protocols that define how we use and interact with the Internet.
Slide 4:A Hierarchy of Networks Every computer that is connected to the Internet is part of a network. For example, you may use a modem and dial a local number to connect to an Internet Service Provider (ISP).
At work, you may be part of a local area network (LAN), but you most likely still connect to the Internet using an ISP that your company has contracted with. When you connect to your ISP, you become part of their network. The ISP may then connect to a larger network and become part of their network. The Internet is simply a network of networks.
Slide 5:Internet Infrastructure A key hardware component of the internet, is a device know as a Router.
Routers are specialized computers that send your messages and those of every other Internet user speeding to their destinations along thousands of pathways.
Slide 7:A Router joins two or more networks, passing information from one to the other. It also protects the networks from one another, preventing the traffic on one from unnecessarily spilling over to the other. Regardless of how many networks are attached, the basic operation and function of the router remains the same.
Routers are physically interconnected via what are know as Backbones.
Slide 8:Backbones Backbones are typically fiber optic trunk lines. The trunk line has multiple fiber optic cables combined together to increase the capacity. Fiber optic cables are designated OC for optical carrier, such as OC-3, OC-12 or OC-48. An OC-3 line is capable of transmitting 155 Mbps while an OC-48 can transmit 2,488 Mbps (2.488 Gbps). Compare that to a typical 56K modem transmitting 56,000 bps and you see just how fast a modern backbone is.
Slide 10:Today there are many companies that operate their own high-capacity backbones, and all of them interconnect at various points around the world. In this way, everyone on the Internet, no matter where they are and what company they use, is able to talk to everyone else on the planet.
The entire Internet is a gigantic, sprawling agreement between companies to intercommunicate freely.
Slide 11:Internet Protocol: IP Addresses Every machine on the Internet has a unique identifying number, called an IP Address. The IP stands for Internet Protocol, which is the language that computers use to communicate over the Internet. A protocol is the pre-defined way that someone who wants to use a service talks with that service. The "someone" could be a person, but more often it is a computer program like a Web browser. A typical IP address looks like this: 216.27.61.137
Slide 12:Internet Protocol: Domain Name SystemWhen the Internet was in its infancy, it consisted of a small number of computers hooked together with modems and telephone lines. You could only make connections by providing the IP address of the computer you wanted to establish a link with.
This was fine when there were only a few hosts out there, but it became unwieldy as more and more systems came online.
Slide 13:In 1983, the University of Wisconsin created the Domain Name System (DNS), which maps text names to IP addresses automatically.
This way you only need to remember for example www.anbell.net, for example, instead of anbell.nets IP address.
Slide 14:Domain Name Server (DNS) Each ISP must maintain a DNS.
DNS servers accept requests from programs and other name servers to convert domain names into IP addresses. When a request comes in, the DNS server will typically answer the request with an IP address for the requested domain.
Slide 15:The ISPs ISP Each local ISP, such as Anbell, acquires its connection to the internet from a larger international carrier. These larger carriers are know as upstream providers.
Upstream providers subdivide and resell locally, their connections to the larger international internet backbones.
Slide 16:The ISPs ISP
Slide 17:Your ISP In the same way that large upstream providers resell service to a local ISP, the local ISP further subdivides and resells service to you the end user of the internet.
ISPs in Jamaica can deliver service by several methods, most commonly used are: Dial-Up, Wireless and ADSL.
Slide 18:Methods of Internet Connectivity
Slide 19:Dial-Up Worldwide, Dial-Up usage is still the primary method of accessing the internet and Jamaica is no exception.
Its main disadvantage is that it is the slowest of all the available methods.
The advantages are that it is portable, and cheap.
Slide 20:Wireless Wireless Service continues to gain popularity in Jamaica.
The main disadvantage is cost of both the ISP and customer equipment.
Advantage: much higher speeds than dial-up & in some instances mobility no physical cable connection.
Slide 21:ADSL ADSL is fast becoming the local standard for high speed access.
Disadvantages: requires phone line access with 3 miles of exchange & is not portable.
Advantage: Very reliable where available & capable of speeds in excess of T1 or 1.5mpbs.
