NHD computer and networking basic

Customer Care
Computer & Networking Basics

01 December 2007






Copyright Notice








The information in this document is subject to change without notice. Published by TWC Customer Care Support Delivery.
This document contains confidential and internal information and is copyrighted. All rights reserved. No part of this document may be photocopied or reproduced by any means without prior consent of TWC’s Customer Care Support Delivery.
© 2007, Time Warner Cable Customer Care Support Delivery, All Rights Reserved.
Road Runner logo and character images TM & © Warner Bros. Entertainment Inc (s07)

Table of Contents

Introduction.. 1
Objectives. 1
Hardware versus Software.. 2
Examples of Computer Hardware. 2
Software. 3
Internet Access.. 5
Internet Browsing.. 7
Internet Protocol Addresses.. 8
IP Address for the Cable Modem.. 8
IP Address for the Interface or CPE.. 8
Common IP Address. 9
Dynamic IP.. 9
Static IP.. 9
Packets.. 10
Networking.. 12
LAN – Local Area Network. 13
Basic Cable Modem Network Topology. 15
Home Network: Router Versus Hub. 16
Proxy Servers.. 18



Introduction
This section will introduce you to the fundamentals of how a computer is structured. It also introduces you to the backbone of how the Internet functions and communicates with the client’s computer.

Objectives
At the end of this section the participant will be able to:
· Explain the components of a computer.
· Define the Internet and its setup.
· Describe the process of browsing the Internet.

Hardware versus Software
Hardware is the physical aspect of computers, telecommunications, and other devices. The term arose as a way to distinguish the "box" and the electronic circuitry and components of a computer from the software program you put in it to make it do things.
Software is a general term for the various kinds of programs used to operate computers and related devices.
Hardware implies permanence and invariability. Software or programming can easily be varied. You can put an entirely new software program in the hardware and make it create an entirely new experience for the user. You cannot, however, change the modular configurations that most computers come with by adding new adapters or cards that extend the computer's capabilities.

Examples of Computer Hardware
Hardware includes not only the actual computer but also the:
· Processes or programs
· Memory (RAM – Random Access Memory)
· File input and output
· Device input and output
· Storage
· Mother Board
· Power Supply
· Floppy and / CD ROM
· Port devices
· Mouse
· Keyboard - Short Cut Keys
♦ Ctrl:
§ A – All
§ X – Cut
§ C – Copy
§ V – Paste
§ P – Print
♦ Alt Tab (one program to another)
· Printer
· Audio speakers
· Processor speed
· Peripherals


Software
Software is often divided into application software (performs a specific function directly for the user) and system software (which includes operating systems and any program that supports application software). The Microsoft Office Suite is an example of application software. Windows Vista is an example of system software.
The term middleware is sometimes used to describe programming that mediates between application and system software or between two different kinds of application software (for example, sending a remote work request from an application in a computer that has one kind of operating system (XP) to an application in a computer with a different operating system (MAC OS X).

Application Software
General kinds of application software include:
· Presentation software, such as Microsoft PowerPoint
· Graphics software for graphic designers, such as Visio and ArtWorks
· Specialized scientific applications
· Productivity software, which includes word processors, spreadsheets, and tools for use by most computer users

System Software – Email Clients
Email clients are also considered forms of software which are stored on the customer’s computer and used to transmit electronic communication across networks.

The major email clients supported by Road Runner are:
· Outlook
· Outlook Express
· Windows Mail (Vista)
· Mac Mail

Email can also be obtained from a web-based platform which is generated directly from an email server that is attached to an HTML interface. These include Road Runner’s Web Mail 4.0 and other commonly known web-based email applications, such as Hotmail and Yahoo.
The user is given a username and password that allows access into the mail server. Once access is granted, all standard email functions are allowed.

System Software – Operating Systems
An operating system (sometimes abbreviated as "OS") is the program that, after being initially loaded into the computer, manages all the other programs in a computer. The operating system is the computer’s resource manager. Operating systems contain specific requirements in order to process information efficiently with each component. The most commonly known are Windows for PC users and Safari for Macintosh users.
The requirements for Road Runner include.
· Adequate amounts of hard drive space
· Processor speed
· Memory


Internet Access
At the onset of the Internet, phone lines were used to transmit the data. The data speed over the phone line started at 9600 Baud. Then it increased to 14.4 kilo bits per second (14K) and 28.8 K. The current speed for a (residential) phone line is 56K.
High speed Internet access is becoming the norm. 56k modems just are not fast enough to derive the full benefit of the newer Internet content.
Cable Modem - A cable modem links your PC to the Internet through a cable TV line. Data can be transmitted and received at around 1Mb per second.
DSL - DSL is an acronym for Digital Subscriber Line, a technology that brings a high bandwidth connection to homes carried through regular copper telephone lines.

T1 - T1 is a term coined by AT&T that refers to a DS1 digital signal that can be transmitted at 1.544 megabits per second.

T3 - T3 is a term for a communications line that transmits data at 44.746 Megabits per second. T3s are most used by ISPs and very large websites.

Internet Access – Continued
ISDN -ISDN is an acronym for Integrated Services Digital Network which is a digital transmission over copper telephone wire. Transfer rates max out at 128 kbps.

Examples of network hardware connections to the computer are:

Ethernet
USB

Road Runner utilizes the USB and Ethernet technologies for computer and modem connections.
· The Ethernet connection utilizes a Network Interface Card (NIC). The NIC connects the PC to the modem and stores the required Internet Protocol address to transfer data across the Road Runner network.
· The USB connection utilizes a port within the computer and drivers (device files that control the hardware components) for the device that is being connected. The USB connection works as a virtual NIC for subscribers that do not have a NIC.

NOTE: A client CANNOT use both an Ethernet cord and USB cord at the same time to connect their modem to their computer. This will confuse the devices and prohibit the ability to surf the Internet! You will learn this later as a troubleshooting step for connectivity issues.

Simile of the Backside of a Computer

Internet Fundamentals
The following information is not specific to cable modems, but rather applies to any device utilized to connect to the Internet as well as the Internet as a whole. Understanding these basics will help determine the benefits of high speed cable Internet.

Bits and Bytes Fundamentals

b
bits
B
Bytes
k or K
Kilo or thousand
m or M
Mega or million

There are 8 bits in a Byte.

Bandwidth speed is measured as the number of bits or Bytes per second (ps). It can be displayed using any of these forms:

bps
bits per second
Bps
Bytes per second
kbps
kilobits per second
kBps *
kiloBytes per second
mbps
megabits per second
mBps
megaBytes per second

Netscape Communicator and Microsoft Internet Explorer will display download speeds in kilobytes per second (kBps)


Cable Modem Speeds
From bits to kilobits to megabits:


bps
kbps
mbps

bits per sec
kilobits per sec
megabits per sec
Download speeds
1,500,000
1,500
1.5
Upload speeds
300,000
300
.3


Bits and Bytes Translation
Converting bits to Bytes:


bps
Bps
kBps

bits per sec
Bytes per sec
kilo Bytes per sec
Download speeds
1,500,000
187,5000
187.5
Upload speeds
300,000
37,500
37.5

Time it takes to download a 10 Megabyte file:
Speed
Connection Type
Transfer Time
28.8 kbps
Analog modem
2 hours
33.6 kbps
Analog modem
1.5 hours
56 kbps
Analog modem
1 hour
128 kbps
ISDN dual channel
20 minutes
1.5 mbps
T1, xDSL, or cable modem
1 minute
4 mbps
xDSL or cable modem
30 seconds
10 mbps
xDSL
10 seconds


Internet Browsing
A web browser is a software application that allows users to view web sites on the Internet. It will also allow users to send and receive electronic mail (better known as e-mail) messages worldwide nearly instantaneously and read messages from newsgroups (forums about thousands of topics in which users share information and opinions).
Sites that are produced for the Internet must take various Web browsers into consideration. Different browsers can have radically different capabilities and limitations.
Some sites try to support all existing browsers while others try to support only the newest and most popular browsers.

Examples of web browsers are:
· Internet Explorer
· Safari / Mozilla
· Opera

In order to browse the web, an address is needed to reach a destination. That address is known as a Universal Resource Locator (URL).

Usually, URLs consist of four parts:
· Protocol
· Server (or domain)
· Path
· Filename

Note: Sometimes, there's no path or file name.
Here's an example of an URL:
· http://www.roadrunner.com/browser/index.html

The breakdown of the above URL is as follows:
· http:// - is the protocol.
· www.roadrunner.com is the server or domain name.
· /browser/ is the path.
· index.html is the filename

Internet Protocol Addresses
Each computer (known as a host) on the Internet has at least one IP address that uniquely identifies it from all other computers on the Internet. For example, just as your home address tells others where to send you mail, an IP Address is a number that lets servers on the Internet know where to send email, web pages, and other data.
Each subscriber that has Road Runner High Speed Internet service will receive two IP addresses. One is for the cable modem and the other one is for the device that connects the cable modem to the computer, such as the NIC (Network Interface Card) or USB (Universal Serial Bus) Port.
These two IP addresses are a little different from each other.

IP Address for the Cable Modem
The IP address for the cable modem is given from the DHCP server and is used to provide authentication for the cable modem to be on our network.
· It is an internal IP address that is given and it is virtually static. This means that IP address is not broadcasted out during the time the subscriber is surfing online.
· It also means that IP address will not change unless we reboot the cable modem. Format for a cable modem’s IP address is: 10.254.54.112.
· The cable modem IP addresses normally start with a 10.x format.

IP Address for the Interface or CPE
The IP address for the Network Interface Card (NIC) or the USB Port (which acts as virtual NIC) is also assigned by the DHCP server. This IP address is different.
· It can change during the time the subscriber is surfing. It is dynamic.
· This IP address is also broadcasted during surfing. This allows the information (in packets) to find the correct place to be sent while looking at different sites on the web.
· The time between changes depends on the local system and the amount of lease time given for the IP address. For example, lease times can be set by the MSO for such time periods as 3, 6, or 24 hours per lease.
· If the lease is not renewed, surfing capability will be lost. Therefore, if the subscriber wants to continue surfing, the DHCP server will assign a new IP address. The format for the IP address is: 67.112.1.121 or 68.12.13.114. Most of these IP addresses start with a 67.x or 68.x format.

Common IP Address
Some RR Issued IP Addresses (There are a lot more!)
24.x.x.x
68.x.x.x
69.x.x.x
70.x.x.x
Router-issued IP Addresses always begin with 192.
192.168.x.x
Computer-issued Invalid IP Addresses always begin with 169.
169.254.x.x
Modem-issued IP Addresses normally start with 10.
10.248.x.x
10.249.x.x
10.250.x.x
Macintosh Airport Router always starts with a 10.
10.x.x.x
Windows Default always defaults to zeros
0.0.0.0

Dynamic IP
One dynamic IP address is provided to each High-Speed Internet customer.
This address is assigned from a pool (large list) of available IP addresses. The address changes periodically. For example, the address changes whenever the modem stops and re-establishes a connection to the Road Runner network…hence, the term "dynamic".

Static IP
A static IP address is a number (in the form of a dotted quad x.x.x.x) that is assigned to a computer by an Internet service provider (ISP) to be its permanent address on the Internet. Computers use IP addresses to locate and talk to each other on the Internet much the same way that people use phone numbers to locate and talk to one another on the telephone. When you want to visit whatis.com, your computer asks a domain name system (DNS) server (think telephone information operator) for the correct dotted quad number (think phone number) for whatis.com, and your computer uses the answer that it receives to connect to the whatis.com server.
It would be simple if every computer that connects to the Internet could have its own static IP number, but when the Internet was first conceived, the architects didn't foresee the need for an unlimited number of IP addresses. Consequently, there are not enough IP numbers to go around. To get around that problem, many Internet service providers limit the number of static IP addresses that they allocate and economize on the remaining number of IP addresses they possess by temporarily assigning an IP address to a requesting Dynamic Host Configuration Protocol (DHCP) computer from a pool of IP addresses. The temporary IP address is called a dynamic IP address.
At this time, static IP addresses are only offered to our Business Class customer accounts.

Packets
When you send or receive data (for example, an e-mail note or a webpage), the message gets divided into little chunks called packets.
Each of these packets contains both the sender's Internet address and the receiver's address. Packets are sent first to a gateway computer that understands a small part of the Internet.
The gateway recognizes the packet as belonging to a computer within its immediate neighborhood or domain. Packets can arrive in a different order than the order they were sent in.
The Internet Protocol just delivers them. It's up to another protocol, the Transmission Control Protocol (TCP) to put them back in the right order.

These packets are composed of different layers in how the data is handled throughout the communication process. Each layer has its own function throughout the process.
· The Physical Layer states what medium the packet will be transmitted over, such as fiber or cable.
· The Data Layer is the packet addressing or the envelope for the packet and is used for error detection.
· The Network Layer is for Internet routing, packet fragmentation, and reassembly along with error checking.
· The Transportation Layer varies depending on the different information contained with the packet but includes making sure the transport of the packet was complete, end to end error checking, and data flow controls.
· The Session Layer starts, maintains, and ends the dialog between the source computer and the end computer during the transmission of the data.
· Presentation Layer controls the appearance of the data throughout the communication ensuring that different systems can receive the data (for example, UNIX Server to a Microsoft computer.)
· Application Layer controls what types of applications can use the data if it be email (SMTP or POP3,) webpage (HTTP,) or data (FTP).

Packet Layers:
Reverse the above (here is an analogy):
· Physical
· Data
· Network
· Transportation
· Session
· Presentation
· Application
· All
· People
· Seem
· To
· Need
· Data
· Processing


Networking
In information technology, a network is a series of points or nodes (a node is a connection point) interconnected by communication paths. Networks can interconnect with other networks and contain sub-networks.

The most common topology (a description of any kind of locality in terms of its layout) or general configurations of networks include the bus, star, Token Ring, and mesh topologies. Networks can also be characterized in terms of spatial distance (how far away they are from each other) as local area networks (LANs), metropolitan area networks (MANs), and wide area networks (WANs).


A given network can also be characterized by the type of data transmission technology that is used on it.
For example, a TCP/IP “Transmission Control Protocol/Internet Protocol” or Systems Network Architecture network) can be characterized by:
· Whether it carries voice, data, or both kinds of signals
· By who can use the network (public or private)
· By the usual nature of its connections (dial-up or switched, dedicated or non-switched, or virtual connections)
· By the types of physical links (for example, optical fiber, coaxial cable, and Unshielded Twisted Pair - copper telephone wiring).

Large telephone networks and networks using their infrastructure (such as the Internet) have sharing and exchange arrangements with other companies so that larger networks are created.

LAN – Local Area Network
A LAN may serve as few as two or three users or as many as thousands of users.

There are several different types of LANs. They are named after the pattern of their communication topologies.

Star Topologies – computers are linked by a central router.


LAN – Local Area Network – Continued
Bus Topologies – computers are linked by a central cable or backbone. This is always used to connect devices together.


Token Ring Topologies – computers are linked to each other.


Basic Cable Modem Network Topology
The basic cable modem network topology or makeup is important to understand since we are one of the teams supporting this network. Start with DHCP and follow along with the picture below.
Note: The STAR topologies are mostly used in companies.
· DHCP (Dynamic Host Configuration Protocol) – Computer that assigns IP addresses to different equipment on the network. DHCP: Allows the network admin to assign IP address.
· DNS (Domain Name System) server – Computer that “translates” web addresses “domain names” to IP addresses. This allows subscribers to surf.
· Provisioning Server – Gives permission for a cable modem on our network and gives it the settings to be connected to the network.
· CMTS – Cable Modem Termination System, which acts as a link between the analog cable network and the digital network.
· Fiber Optic Cable – Allows for more bandwidth through the network and better quality of signal.
· Fiber Optic Node – Translates digital signals to an analog signal through the coax cable.
· Coax Cable Trunk – Carries the signal from the Fiber Node to the feeder lines.
· Coax Cable Feeder – Feeder lines “feed” the tap for a subscriber drop
· Subscriber Drop – The cable line that sends the signal into the house and to the cable modem.

Home Network: Router Versus Hub
A Router is “smart”, meaning that it recognizes each PC and offers the connection to each as it is specifically configured by the owner.

A Hub does not recognize the devices (PCs) that are connected to it on an individual basis, but offers only one IP unless the customer orders a second dynamic IP address. The customer receives one with their service and can normally order additional ones according to divisional offerings and pricing.

Router Communication

HUB Communication

Proxy Servers
We do not use a proxy server here at Road Runner. However, in our troubleshooting, it is important to understand what a proxy server does. We will cover what issues can arise from running a proxy server with our service later in the training course.

In an enterprise that uses the Internet, a proxy server is a server that acts as an intermediary between a workstation user and the Internet so that the enterprise can ensure security, administrative control, and caching service. A proxy server is associated with or part of a gateway server that separates the enterprise network from the outside network and a firewall server that protects the enterprise network from outside intrusion.

A proxy server receives a request for an Internet service (such as a webpage request) from a user. If it passes filtering requirements, the proxy server, assuming it is also a cache server, looks in its local cache of previously downloaded web pages. If it finds the page, it returns it to the user without needing to forward the request to the Internet. If the page is not in the cache, the proxy server, acting as a client on behalf of the user, uses one of its own IP addresses to request the page from the server out on the Internet. When the page is returned, the proxy server relates it to the original request and forwards it on to the user.

To the user, the proxy server is invisible; all Internet requests and returned responses appear to be directly with the addressed Internet server. (The proxy is not quite invisible; its IP address has to be specified as a configuration option to the browser or other protocol program.)

An advantage of a proxy server is that its cache can serve all users. If one or more Internet sites are frequently requested, these are likely to be in the proxy's cache, which will improve user response time. In fact, there are special servers called cache servers. A proxy can also do logging.