Chapter 12 A Manager s Guide to the Internet and Telecommunications 12 2 Internet 101 Understanding How the Internet Works Internet service provider ISP an organization firm that provides access to the internet Verizon Comcast AT T The internet has no center and no one owns it internet was designed to be redundant and fault tolerant meaning that if one network fails everything else should keep running For my computer to communicate with another computer on the internet it needs to answer 3 questions o What are you looking for When you type an address into a web browser URL aka web address uniform resource locator you are telling your browser what you are looking for Hypertext transfer protocol application transfer protocol that allows web browsers and web servers to communicate with each other http Protocol is a set of rules for communication FTP file transfer protocol used to copy files from one computer to another Domain name of the network you are trying to connect to Host the computer you are looking for on that network Domains can have lots of different hosts www yahoo com sports yahoo com Host and domain names are not case sensitive Load balancing distributed a computing workload across multiple systems to avoid congestion and slow performance Fault tolerance the ability of a system to continue operation even if a component fails Web hosting services a firm that provides hardware and services to run other people s websites Internet Corporation for Assigning Names and Numbers ICANN a nonprofit governance and standards setting body responsible for managing internet domain Generic top level domains gTLD com net org Cybersquatting acquiring a domain name with the goal of exploiting it for financial gain illegal The path maps to a folder location where the file is stored on the server the file is the name of the file you re looking for Hypertext markup language language used to compose web pages html o Where is it and how do we get there IP address used to identify a device that is connected to the internet usually a string of 4 numbers between 0 and 255 separated by 3 periods Network address translation NAT a technique often used to conserve IP addresses uses a gateway that allows multiple devices to share a single IP address Transitioning from IPv4 to IPv6 shifting IP schemes Domain name service DNS internet directory service that allows devices services to be named and discovered helps your browser locate the appropriate computer when you enter www google com aka phonebook Cache a temporary storage spaced used to speed computing tasks once you have entered a host or domain name and the IP address was found the computer will store it Key Takeaways o The Internet is a network of networks Internet service providers connect with one another to share traffic enabling any Internet connected device to communicate with any other o URLs may list the application protocol host name domain name path name and file name in that order Path and file names are case sensitive o A domain name represents an organization Hosts are public services offered by that organization Hosts are often thought of as a single computer although many computers can operate under a single host name and many hosts can also be run off a single computer o You don t buy a domain name but can register it paying for a renewable right to use that domain name Domains need to be registered within a generic top level domain such as com or org or within a two character country code top level domain such as uk ly or md o Registering a domain that uses someone else s trademark in an attempt to extract financial gain is considered cybersquatting The United States and other nations have anticybersquatting laws and ICANN has a dispute resolution system that can overturn domain name claims if a registrant is considered to be cybersquatting o Every device connected to the Internet has an IP address These addresses are assigned by the organization that connects the user to the Internet An IP address may be assigned temporarily for use only during that online session o We re running out of IP addresses The current scheme IPv4 is being replaced by IPv6 a scheme that will give us many more addresses and additional feature benefits but is not backward compatible with the IPv4 standard Transitioning to IPv6 will be costly take time and introduce delay when traffic transfers between IPv4 and IPv6 networks o The domain name system is a distributed fault tolerant system that uses nameservers to map host domain name combinations to IP addresses 12 3 Getting Where You re Going Transmission control protocol TCP works at both ends of most internet communication to ensure a perfect copy of a message is sent a web server wants to send you a large web page web server hands the web page to its own version of TCP TCP slices up the web page into smaller chunks of data called packets datagrams the packets are like envelopes containing part of the entire transmission Internet protocol IP in charge of getting the packets to their final destination o Packets probably have to travel over several networks to get to their destination this relay work is done via special computers called routers connects networks and exchanges data o Every computer on the internet is connected to a router and all routers are connected to at least one other router Once packets are received by the destination computer that machine s version of TCP kicks in puts the packet back together User datagram protocol UDP same thing as TCP but faster and therefore poorer quality internet Voice over internet protocol VoIP phone calls that take place over the o Circuit switching a dedicated connection between 2 entities o Swap circuit switching s quality of service with packing switching s efficiency and cost savings Routers are connected together either via cables or wirelessly Peering when separate internet service providers link their networks to swap traffic on the internet usually take place at neutral sites called internet exchange points IXPs Colocation facility provides a place where the gear from multiple firms can come together where peering can take place high speed Key Takeaways o TCP IP or the Internet protocol suite helps get perfect copies of Internet transmissions from one location to another TCP works on the ends of transmission breaking up transmissions up into manageable packets at the start and putting them back together while checking quality at the end IP works in
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