Week 1 Computer Networking 1 ( Internet, DSL, Fiber to Home )

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1 Week 1 Computer Networking 1 ( Internet, DSL, Fiber to Home ) Instructor : Nasmee Salaeh nasmees@gmail.com Keyword Dial up Refers to connecting a device to a network via a modem and a public telephone network. Dial-up access is really just like a phone connection, except that the parties at the two ends are computer devices rather than people. Because dial-up access uses normal telephone lines, the quality of the connection is not always good and data rates are limited. In the past, the maximum data rate with dial-up access was 56 Kbps (56,000 bits per second), but new technologies such as ISDN are providing faster rates. DSL Digital subscriber line technology transmits data over phone lines without interfering with voice service. ADSL Asymmetric digital subscriber line, ADSL is a type of DSL broadband communications technology used for connecting to the Internet. ADSL allows more data to be sent over existing copper telephone lines (POTS), when compared to traditional modem lines. A special filter, called a microfilter, is installed on a subscriber's telephone line to allow both ADSL and regular voice (telephone) services to be used at the same time. DSLAM Digital Subscriber Line Access Multiplexer is a network device, usually at a telephone company central office, that receives signals from multiple customer Digital Subscriber Line (DSL) connections and puts the signals on a high-speed backbone line using multiplexing techniques. Mbps Megabits per second refer to megabytes per second which are units of data transfer speed ISP Internet service provider is an organization that provides services for accessing, using, or participating in the Internet. Internet service providers may be organized in various forms, such as commercial, community-owned, non-profit, or otherwise privately owned. DHCP Dynamic Host Configuration Protocol, a protocol for assigning dynamic IP addresses to devices on a network. With dynamic addressing, a device can have a different IP address every time it connects to the network. In some systems, the device's IP address can even change while it is still connected. DHCP also supports a mix of static and dynamic IP addresses. DNS Domain Name System (or Service or Server), an Internet service that translates domain names into IP addresses. Because domain names are alphabetic, they're easier to remember. The Internet however, is really based on IP addresses. Every time you use a domain name, therefore, a DNS service must translate the name into the corresponding IP address. For example, the domain name might translate to

2 Dial-Up Dial-up Internet access is a connection type that operates through a standard telephone line. By running the telephone line to a modem device in the computer and configuring it to dial a specific phone number, the computer can connect to the Internet. This connection type is usually inexpensive, but slow, and may not be adequate for users who use the web for multimedia and other high-bandwidth applications. How It Works This type of Internet access is offered through a number of Internet service providers (ISPs). Most ISPs lease a set of telephone numbers sometimes local, sometimes national that allow a computer to send information to network pipelines that feed into the Internet. Subscribers to the ISP normally pay a monthly or yearly fee for online access at any time of the day or night. Before a person can subscribe to a dial-up service, he or she must have a computer and the right type of modem. A modem is a device that converts digital data into signals that can be sent over the phone line; some models fit into a free slot inside the computer, while others are external and connect to the machine with a cable. A telephone line is plugged into the modem to connect it to the phone system. The modem is controlled by software in the computer which allows the user to set up a profile for the ISP, which will tell the modem what phone number to call and how to communicate with the service. Once the modem calls the phone number and makes a connection, a "handshake" takes place in which information is exchanged between the computer modem and the remote server. The subscriber chooses a username and password or has one assigned by the ISP, and this information is transmitted by the modem to allow the user to connect to the service. DSL architecture

3 How DSL Work This is you that want to connect to internet First, a DSL provider like CenturyLink provides the physical telephone line to YOU. After you connect your modem to the phone line, the modem looks for the DSL provider. After the modem 'finds' the DSL provider, the DSL light on your modem will turn solid green Next, your DSL Provider hands off your 'username' and 'password' to your ISP. See the list of 3rd party ISP's. Third party ISP's are not available in all areas or compatible with all DSL technologies. When your Internet light turns GREEN*, your ISP has accepted the 'username' and 'password' stored in your modem. This does not apply to ISPs that use bridging. Finally, your ISP connects you to the Internet. The Internet light on your modem quickly flashes GREEN to let you know you are sending/receiving information.

4 Google Fiber ( Kansas City ) If you work or live in the Kansas City area, in the last week you ve probably noticed Google workers out hanging fiber on utility poles and digging holes to install fiber underground. Over 100 miles of fiber has been hung, and Kansas City is well on it s way to getting faster, more efficient internet capabilities. So how does it work? According to Google s Fiber Blog: Google will route fiber connections into Kansas City, KS and Kansas City, MO through several equipment aggregator huts. From there, the fiber cables will travel along utility poles into neighborhoods and homes. Every home that has Google Fiber service will have their very own fiber-optic cable that directly connects all the way back to the Internet backbone. Google Fiber users will be able to download and upload files at the exact same speed, enabling users to upload large files in seconds rather than minutes or sometimes hours. Google fiber structure

5 DNS architecture Linux Commands $ ifconfig used for displaying current network configuration information, setting up an ip address, netmask or broadcast address to an network interface, creating an alias for network interface, setting up hardware address and enable or disable network interfaces. $ host (example : $ host facebook.com) is a simple utility for performing DNS lookups. It is normally used to convert names to IP addresses and vice versa. When no arguments or options are given, host prints a short summary of its command line arguments and options. $ traceroute (example : $ traceroute facebook.com) he Internet is a large and complex aggregation of network hardware, connected together by gateways. Tracking the route one's packets follow (or finding the miscreant gateway that's discarding your packets) can be difficult. Traceroute utilizes the IP protocol `time to live' field and attempts to elicit an ICMP TIME_EXCEEDED response from each gateway along the path to some host.

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