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Title: Intro%20to%20Networking

Intro to Networking
  • Philip Ashman
  • Asst. Prof. Okanagan College
  • Dept of Network Telecommunications Engineering

(No Transcript)
  • A quick note of reference. The information
    contained in this presentation is all information
    that has been and can be readily found on the
  • You are free to use and borrow this material as I
    have borrowed from others.
  • The goal is to provide a basic understanding of
    common networking and security terminology, as
    well as some of the next generation internet
    services known as Web 2.0.
  • The scope of this presentation is far too wide to
    cover any one of the aforementioned topics in
    detail, but as usual our good friends at Google,
    Wikipedia, and Cisco can provide you with more
    information than you could possibly consume!

What is a Network
  • Computer networking is the scientific and
    engineering discipline concerned with
    communication between computer systems. Such
    networks involve at least two devices capable of
    being networked with at least one usually being a
    computer. The devices can be separated by a few
    meters (e.g. via Bluetooth) or thousands of
    kilometers (e.g. via the Internet). Computer
    networking is sometimes considered a
    sub-discipline of telecommunications.
  • Quoted from Wikipedia

Intro to Networking
  • Sharing hardware or software
  • E.g. print document
  • Centralize administration and support
  • E.g. Internet-based, so everyone can access the
    same administrative or support application from
    their PCs

Computer Networking Models
  • Models, or protocol stacks, are organized into
    layers. This organizes the process into modules
    simliar to breaking programming code into

OSI-7 Layer Model DOD 3-Layer Model Simplified 4/5-layer Model Simplified 4/5-layer Model Simplified 4/5-layer Model
7 Application Application Application
6 Presentation Application Application
5 Session Application Application
4 Transport Protocol Transport
3 Network Protocol Newtork
2 Data Local Network (LAN) Data
1 Physical Local Network (LAN) Physical
OSI (Open Systems Interconnection) mnemonic All
People Seem To Need Data Processing If you ever
take a test on networking, youll have to now
this, otherwise it is best to stick to the
simplified model.
Simplified 4/5 Layer Model
  • Data Link Physical Layer (Layer 1 2) Most
    common protocol and media is Ethernet over copper
    twisted pair or fiber optic cable. Usually
    referenced as 10Base, 100BaseT, 1000BaseT for
    10/100/1000Mbit/s on Twisted pair, or 10BaseFX,
    100BaseFL, 1000BaseSX/LX/ZX for 10/100/1000Mbit/s
    over Fiber optics.The max distance for a single
    10/100/1000 BaseT connection is 90M 10M for
    patch cables.
  • Transport/Network Layer (Layer 3 4) Most common
    protocol is TCP/IP. IP is used at layer 4 to
    control the addressing, TCP/UDP is used at layer
    3 for flow control and connection management
  • Application Layer (Layer 5,6 7) Applications
    that use the Layer 3/4 protocols to communicate.
    Eg our Web Browsers, network printing, file
    sharing, skype, msn messenger etc

Intro to Networking
  • Depending on ones perspective, we can classify
    networks in different ways
  • Based on transmission media Wired (UTP, coaxial
    cables, fiber-optic cables) and Wireless
  • Based on network size LAN and WAN (and MAN)
  • Based on management method Peer-to-peer and
  • Based on topology (connectivity) Bus, Star, Ring

Transmission Media
(No Transcript)
Transmission Media
  • Two main categories
  • Guided
  • Twisted-Pair cables
  • Unshielded Twisted-Pair (UTP) cables
  • Shielded Twisted-Pair (STP) cables
  • Coaxial cables
  • Fiber-optic cables
  • UnGuided
  • Wireless transmission, e.g. radio, microwave,
    infrared, sound, sonar

Twisted Pair Cable
  • Most desktop network connections consist of 24
    gauge copper wires twisted into pairs.
  • Twists in wire keep down interference from
    electro magnetic interference (fluorescent
    lights, motors etc..)
  • The quality and specifications of the twisted
    pair cables are categorized into a number of
    categories, but most users today are familiar
    with Cat5/5e or Cat6
  • Cat6 has more twists than Cat5e and allows for
    higher frequencies. Cat5e and above is
    recommended for all networking installations,
    although for Gigabit ethernet use Cat6 if

Twisted Pair Cable
  • The wiring within a building usually and to the
    data outlet in the wall uses a solid copper core
    whereas a patch cable connecting your computer to
    a wall.
  • If the pair of wires is not twisted, interference
    will affect the closer wire more than the further
    one, thereby causing errors.
  • Twisting the pairs allows for the interference to
    spread equally over each pair allowing for common
    mode interference cancellation

Twisted-Pair Cables
  • By sending half the signal down one wire in a
    pair, negating half the signal and sending it
    down the other wire in the pair, a subtraction at
    the other end will bring the signal back to its
    original amplitude and cancel out the

Unshielded Twisted-Pair (UTP)
  • Typically wrapped inside a plastic cover (for
    mechanical protection)
  • UTP consists of 8 Strands, 4 pairs. They are
    usually terminated with an RJ45 connector
    according to the EIA/TIA 568A/B specs which
    indicates the order of the pairs. 10/100BaseT
    uses pairs 2 3 on pins 1,2, 3 6

4 Pairs
Plastic Cover
Shielded Twisted-Pair (STP)
  • STP cables are similar to UTP cables, except
    there is a metal foil or braided-metal-mesh cover
    that encases each pair of insulated wires

Categories of UTP Cables
  • EIA classifies UTP cables according to the
    quality Categories 1,2,4 used to exist, but you
    cant buy them any more
  • Category 3 At least 3 twists per foot, for up to
    10 Mbps (common in phone networks in residential
  • Category 5 (or 5e) Up to 100 Mbps (common for
    networks targeted for high-speed data
  • Category 6 More twists than Cat 5, up to 1 Gbps
    and uses 23 Gauge wire. Also rated up to 10Gbps
    for 35m.

Coaxial Cables
  • In general, coaxial cables, or coax, carry
    signals of higher freq (100KHz500MHz) than UTP
  • Outer metallic wrapping serves both as a shield
    against noise and as the second conductor that
    completes the circuit

Fiber-Optic Cables
  • Light travels at 3?108 ms-1 in free space
  • Refraction occurs when light goes between mediums
    of different densities with light bending away
    from the normal when it enters a less dense
  • The critical angle is the point at which the
    light is reflected back.
  • Beyond the critical angle ? total internal

Fiber-Optic Cables
  • An optical fiber consists of a glass core (denser
    material) and a plastic cladding (less dense
  • Light is transmitted through the core and bounces
    back and forth along the core (as a result of the
    refraction index between the core and cladding)
    at a specific angle called the mode.
  • Common light sources include LEDs and lasers,
    although lasers allow for longer distances.

Fiber Optic Cables
  • Fiber Optic cable usually falls into two major
    categories, either Multi-mode or Single-mode.
  • Multi-mode has a glass core with a diameter of
    about 62.5/50? and allows light to travel at
    multiple angles (modes) down the core at a
    specific wavelength (Usually 850nm or 1300nm)
  • Single mode has a glass core with a diameter of
    about 9 ? and allows light to travel at a
    single angle (mode) down the core at a specific
    wavelength (Usually 1550nm)

Fiber Optic Cables
  • Advantages and Disadvantages
  • Noise resistance External light is blocked by
    outer jacket
  • Less signal attenuation A signal can run for
    miles without regeneration (currently, the lowest
    measured loss is about 4 or 0.16dB per km)
  • Higher bandwidth Currently, limits on data rates
    come from the signal generation/reception
    technology, not the fiber itself
  • Cost Optical fibers are more expensive than
  • Installation/maintenance Any crack in the core
    will degrade the signal, and all connections must
    be perfectly aligned

Protocol Release Date Op. Frequency Data Rate (Typ) Data Rate (Max) Range (Indoor)
Legacy 1997 2.4 -2.5 GHz 1 Mbit/s 2 Mbit/s  ?
802.11a 1999 5.15-5.35/5.47-5.725/5.725-5.875 GHz 25 Mbit/s 54 Mbit/s 50 meters
802.11b 1999 2.4-2.5 GHz 6.5 Mbit/s 11 Mbit/s 100 meters
802.11g 2003 2.4-2.5 GHz 11 Mbit/s 54 Mbit/s 100 meters
802.11n 2006 (draft) 2.4 GHz or 5 GHz bands 200 Mbit/s 540 Mbit/s 250 meters
  • Protocols in the 2.4GHz range are susceptible to
    interference from microwave ovens, cordelss
    telephones and blue tooth.
  • These are unregulated frequencies, but hopefully
    one or the other is smart enough to hop
    frequencies and reduce interference
  • 802.11b and g devices can use the same access
    points, but 802.11a requres separate (or dual)
    antennae. (makes sense as it uses a different

  • There are proprietary extensions to boost the
    speed (usually advertised as 108G), but MIMO
    (Multiple-in Multiple-out) will likely be used to
    expand the bandwidth of existing technologies.
  • MIMO is a multi-antenna communication systems
    where the transmitter has multiple antennas
    capable of transmitting independent signals and
    the receiver is equipped with multiple receive
    antennas. Ie send data in parallell.

Wireless Security
  • When setting up your wireless access point learn
    how to log in to it and change the default
  • Create a unique password
  • Create a unique SSID
  • Turn off SSID Broadcast
  • Turn on WPA-2 Pre-Shared Key encryption (may have
    to upgrade firmware)
  • Turn on MAC address filtering
  • Turn down the power settings if you have a small
    area to cover.

Local Area Network (LAN) Wide Area Network (WAN)
(No Transcript)
Local Area Network
  • Small network, short distance
  • A room, a floor, a building
  • Limited by no. of computers and distance covered
  • Usually one kind of technology such as Ethernet
    throughout the LAN
  • Often server a single location within an
  • Examples
  • Network inside a Student Computer Lab
  • Network inside Okanagan College
  • Network inside your home

Wide Area Network (WAN)
  • A network that uses long-range telecommunication
    links to connect 2 or more LANs/computers housed
    in different places far apart.
  • Towns, states, countries
  • Examples
  • Inter/Intra-City Connections
  • Internet

Your home
  • Example WAN technologies
  • ISDN Integrated Service Digital Network
  • BW Basic Rate 192 Kbps Primary rate
  • T-Carriers ? basically digital phone lines
  • BW T1 1.544Mbps T3 28?T1approx 45Mbps
  • Frame relay
  • BW 56K to 1.544Mbps or even higher
  • SONET Synchronous Optical Network
  • BW Multiples of OC1 51.84Mbps
  • Supports OC12 and up to OC192 (9953.28Mbps) or
    even higher in the future

Broadband Cable Network
  • Example of WAN Broadband Cable Network
  • Cable TV services have been extensively developed
    in most modern cities
  • Cable TV companies try to make use of their
    coaxial cable installed (that are supposed to
    carry TV signals) to deliver broadband data
  • Many cable network wiring has been replaced with
    hybrid fiber-coax (HFC) ? i.e. use of fiber-optic
    cable to connect to the subscribers buildings,
    and then the original coaxial cable to connect to
    each household

Broadband Cable Network
The connection is shared by a number of
subscribers, hence may raise performance and
security problems
Fiber-optic cable
Cable Drop
Cable company
Coaxial Cable
Shaw Cable
  • Shaw is also providing an asymmetrical service.
  • Downstream max 25 Mbps
  • Upstream max 1 Mbps
  • Need a special Cable modem

Ethernet link to PC
Terayon Cable Modem
Coaxial link from cable TV socket
Telco Network
  • Example of WAN Telco Carrier ADSL Network
  • Telco services have been in existance since the
    beginning of the telephone
  • Telco companies make use of the existing copper
    phone cable in homes to deliver broadband data
    services via Assymmetric Digital Subscriber Line
  • Telus are currently upgrading their
    infrastructure bring fiber optic cable closer to
    homes and neigbourhoods in order to be able to
    offer higher speed services such as IPTV and
    digital phone services.

Telco Network
Each connection is shared by a number of
subscribers, hence may raise performance and
security problems
Copper Cable
Fiber-optic cable
Local Telco Office
Telco company
Fiber optic
Telus ADSL
  • Asymmetric Digital Subscriber Line (ADSL) is an
    asymmetrical technology
  • Downstream max 36 Mbps
  • Upstream max 10 Mbps
  • May be reduced to 3 10 Mbps downstream and 2
    Mbps upstream, depending on no. of subscribers
  • Need a special ADSL modem

Telus ADSL
  • Depending on whether Telus have your ADSL signal
    come in on the same wires as your telephone, you
    may need to install a Microfilter to avoid poor
    phone quality.
  • Microfilter installation is simple and requires
    no tools or telephone rewiring. Just unplug the
    telephone device from the baseboard or wall mount
    and snap in a microfilter, then snap in the
    telephone device.

Peer to Peer Networks Vs Client Server Networks
(No Transcript)
Peer-to-Peer Networks
  • Peer-to-peer network is also called workgroup
  • No hierarchy among computers ? all are equal
  • No administrator responsible for the network

Peer to Peer Networks
  • Advantages of peer-to-peer networks
  • Low cost
  • Simple to configure
  • User has full accessibility of the computer
  • Disadvantages of peer-to-peer networks
  • May have duplication in resources
  • Difficult to uphold security policy
  • Difficult to handle uneven loading
  • Where peer-to-peer network is appropriate
  • 10 or less users
  • No specialized services required
  • Security is not an issue
  • Only limited growth in the foreseeable future

Clients-Server Networks
  • Network Clients (Workstation)
  • Computers that request network resources or
  • Network Servers
  • Computers that manage and provide network
    resources and services to clients
  • Usually have more processing power, memory and
    hard disk space than clients
  • Run Network Operating System that can centralize
    management of not only data, but also users,
    groups, security, and applications on the network
  • Servers often have a more stringent requirement
    on its performance and reliability

Client-Server Networks
  • Advantages of client/server networks
  • Facilitate resource sharing centrally
    administrate and control
  • Facilitate system backup and improve fault
  • Enhance security only administrator can have
    access to Server
  • Support more users difficult to achieve with
    peer-to-peer networks
  • Disadvantages of client/server networks
  • High cost for Servers
  • Need expert to configure the network
  • Introduce a single point of failure to the system

Network Topology
  • 3 basic types?
  • Bus Topology Ring Topology
  • Star Topology

Network Topology
  • Bus Topology
  • Simple and low-cost
  • A single cable called a trunk (backbone, segment)
  • Only one computer can send messages at a time
  • Passive topology - computer only listen for, not
    regenerate data
  • Star Topology
  • Each computer has a cable connected to a single
  • More cabling, hence higher cost
  • All signals transmission through the center core
    if down, entire network down
  • Depending on the intelligence of core, two or
    more computers may send message at the same time

Network Topology
Bus Topology
Coaxial cable
Star Topology
BNC T-Connector
Network Card
  • Ring Topology
  • Every computer serves as
  • a repeater to boost signals
  • Uses Token passing to send data, where only the
    computer who gets the token can send data
  • Disadvantages
  • Difficult to add computers
  • More expensive
  • If one computer fails, whole network fails

Protocol Basics
(No Transcript)
Ethernet Addressing (Layer 2)
  • Since there can be many users on an ethernet
    network, everyone has to have their own unique
  • This is called the Media Access Control (or MAC)
    address, or sometimes ethernet address, physical
    address, adaptor address, hardware addres, etc.
  • Its a 12-digit (48 bit) hexadecimal address that
    is unique to that ethernet adaptor and no other
    in the world. It can be written as
    00306583fc0a or 0030.6583.fc0a or
    00306583fc0a or 00-30-65-83-fc-0a but they all
    mean the same thing.
  • The first 6 digits are the Vendor code, (003065
    belongs to Apple), the last 6 are the individual
    intefaces own. Like a cars VIN. See
    http// to look up some
    vendor codes.

Hubs vs. Switches
  • Hubs
  • Shared media devices
  • Everyone sees everyones packets but each device
    only pays attention to those specifically
    directed to it, or to broadcasts.
  • Not too secure, but cheap. Most wireless still
    qualifies as a hub, while actual wired ethernet
    hubs are becoming hard to find now.

Hubs vs. Switches
  • Switches
  • Not shared most of the time.
  • The switch pays attention to the packets and
    makes a table of the sender ethernet addresses
    (it removes old data after a while).
  • When a packet comes along whose destination
    address is in the table (because that host has
    recently talked and identified itself) the
    packet only goes to that port.
  • Unknown packets and broadcasts still go to all
    ports, but overall, there are nearly no
    collisions and is generally more secure.
  • Switches are now much more common than hubs.

Finding your Ethernet Address
  • On Windows 95/98, from the run menu type
  • On Windows NT, 2000 and XP, open a command window
    and type ipconfig /all
  • On MacOS 9, open the TCP/IP control panel and
    select Get info
  • On MacOS X and most Unix or Unix-like systems,
    from a terminal, type ifconfig a.
  • This address can be used for the MAC address
    filtering on a wirelss router and is also
    required by Telus in order for a device to
    connect to the Internet on their ADSL network.
    (This can be done online by going to

Network Layer (Layer 3)
  • Devices are connected together with Ethernet
    swithes to form a Network. Networks are connected
    together using Routers to form Internetworks. The
    Internet is one big Internetwork.
  • Each machine on a network has unique layer 2 (eg
    ethernet) address, each Network is assigned a
    unique block of layer 3 (eg Internet Protocol
    (IP) ) addresses. In IP, this is called a subnet.
  • The block of layer 3 addresses uniquely identifes
    a network on the Internetwork, and each layer 3
    address in the block uniquely identifies each
  • Although IP is by far the most predominant
    protocol in use, there are others such as
    AppleTalk, Netware, etc.)

Internet Protocol (IP)
  • Devices talk to each other on an Ethernet network
    using each others MAC Address. However on the
    internet they communicate using IP Addresses.
  • The Internet Protocol (IP) is the Network layer
    protocol used on the Internet! Its so handy that
    most everyone uses it on all their networks big
    and small.
  • Very Scalable allowing it to support the
    ever-expanding Internet.

IP Addressing
  • IP addresses consists of 4 octets such as
  • Each octet consists of numbers between 0 and
    255 (or 00 and FF in hex! Dont ask why ethernet
    is in hex but IP isnt, they just are. However
    the next generation of IP, IPV6, does use hex)
  • An IP Address works is similar to the way a phone
    number has an area code and local prefix etc. but
    more flexible.
  • Your computer can tell when you are trying to
    talk to another network based on an assigned
    subnet mask. (I will explain this if asked, but
    you are opening a whole can of worms!)

IP Domain Name Resolution (DNS)
  • Your company or office is usually assigned a
    block IP addresses by an Internet Service
    Provider such as Telus, or you can apply to get
    your own from ARIN (http//
  • However you can register a Domain name througn
    any number of Internet Name reistrars.
  • Since most people find it easier to remember
    names instead of numbers, IP numbers can and
    almost always are associated with IP Domain
  • Your computer, however, needs a number, so the
    Domain Name System (DNS) exists to make everyone

  • A name, such as
    tells you the first (or top) level domain is
    .ca, for domains in Canda, the second level bc,
    and third that it is part of okanagan colleges
    network. The label Technologies is a specific
    machine on this network.
  • If you want the number for a host name within youll have to ask a DNS server
    to give it to you.
  • Every domain has a local Domain Name server it
    can use, which is found the same way you
    discovered your Ethernet address. (The comand
    ipconfig, or the Support tab of the LAN
    Connection properties in Windows XP

IP Routing
  • IP Routing answers the question of How do you
    get to that network from this one?
  • As mentioned previously, your computer can use
    the IP subnet mask to determine whether the
    destination IP address is on a remote network.
  • If the address is to be sent to a remote network,
    then the data is encapsulated in an IP packet,
    which is encapsulated in an Ethernet Frame and
    sent to the Ethernet address of the local Router,
    or gateway.
  • The router looks inside the Ethernet packet,
    checks out the destination IP address, and makes
    a decision on which interface to repackage the IP
    Packet and send it on its way.

  • A routers job is to keep track of its directly
    connected networks, maybe learn about other
    remote networks, and send traffic to the
    appropriate network based on the Layer 3 address.
    (Of course this is likely to be the IP Address)
  • The router is the traffic cop of the internet.
  • Most home routers usually only have two connected
    networks. One to your home network, and the other
    to the Internet. Therefore it knows that if the
    destination IP address is not on the home
    network, then it simply has to send it on
    upstream to the next router. From then on, that
    is where things get complicated!
  • A great movie describing this process is called
    Warriors of the Net (http//

  • Dynamic Host Configuration Protocol
  • All the information your computer needs to
    communicate on an IP network (eg the IP Address,
    Subnet Mask, Gateway and Domain Name Server) is
    assigned automatically by a server called the
    DHCP server.
  • If you have a small wireless router at home, then
    this router acts as a DHCP server and assigns all
    the appropriate IP information for you home
  • However this router is also a DHCP client since
    it gets its external IP information
    automatically from the upstream services provider
    (Usually Shaw or Telus)

  • You cant introduce networking without including
    the tools Ping and Traceroute.
  • Ping
  • Sends a small packet to a host which may or may
    not choose to reply to it, and logs the time of
    how long the packet takes to get back.
  • Lack of a reply doesnt always indicate a problem
    with the host or network, but its a good start
    toward testing connectivity issues.
  • Unfortunately this ability is also a major
    security threat as hackers have used this tool to
    generate a Denial of Service. Nevertheless, it is
    often used within Local Area Networks.

  • Traceroute
  • Traceroute asks all routers along the path
    between you and the destination host if theyd
    like to respond to you, and logs the time it
    takes each of 3 requests take to get back to you.
  • Some routers may not respond, but may still pass
    the traceroute packet along, and many hosts will
    not reply to the traceroute inquiry at all.
  • Lack of a reply doesnt always indicate a problem
    with the host or network, but again its a good
    start toward looking for bottlenecks.
  • Onces again, there is also a threat of Denial of
    Service attacks using this tool and therefore
    many adminstrators block extneral traceroute
    requests from getting through their Routers.

Security Tips
  • Windows XP Professional Security
  • Setting Up a New PC Safely
  • Secure Windows Configuration
  • Software Tools for Better Security
  • Good Security Practices for You
  • Passwords vs. Pass Phrases
  • Malware and Phishing Scams
  • Windows Security Top 10 List
  • Other Security Resources

Whats the Threat?
  • Viruses, Hackers and Worms - Oh, My!
  • Purists reserve the term hacker for ace
    programmers, not attackers
  • http//
  • Virus is also an overworked term
  • Internet worms, mass-mailing worms, viruses
    (infectors), Trojan Horses, backdoors, rootkits,
    bots, zombie networks, spyware, hijacking
  • The best general term is malware
  • You Get the Idea Its a Jungle Out There!
  • And an oz. of protection is worth a lb. of cure

A Few Assumptions
  • Much of What Follows Assumes That
  • You have administrator rights for your PC
  • If you have local technical support staff, you
    have their blessing to make changes to your PCs
  • You understand that changing security-related
    settings can impair functionality You might have
    to undo some changes

User Rights Privileges
  • What Are Administrator Rights?
  • A User in the Administrators Group
  • Can modify or delete all files, including (with
    some protections) system files
  • Can modify the Windows registry
  • Can define local security policies
  • Has more or less total control
  • Because of How Windows Applications Are Designed,
    Administrator Rights Are Often Necessary for
    Normal Use
  • Primary XP user has administrator rights

Out of the Box
  • You Just Got a New PC Now What?
  • Its not securely configured by default
  • Security software is probably missing
  • The survival time of an unpatched PC
  • See http//
  • First Dont Put It on the Network!
  • Do set strong passwords or pass phrases
  • Do disable File Printer Sharing
  • Do enable the Windows Firewall
  • Do place your machine behind a dedicate firewall
  • Configure Your Network Settings
  • Now you can connect to the Internet

So Youre on the Internet
  • Go to http//
  • Install all critical updates and service packs
  • Reboot and revisit the Windows Update site
  • Lather, rinse, repeat
  • Install Various System tool
  • Download and install an AntiVirus product (AVG,
    PC-Cillen, Nod32, Kapersky, MS Live Onecare)
  • Download and install SpySweeper, MS Defender,

Note on Windows File Sharing
  • Always Disable Unneeded Services
  • File Printer Sharing Is an Open Door, so use
    with caution, certainly use permissions.
  • Go to Start Settings Control Panel
  • Click Switch to Classic View
  • Double-click Network Connections
  • Right-click Local Area Connection
  • Choose Properties
  • Uncheck File and Printer Sharing

Passwords vs. Pass Phrases
  • Security A Tradeoff with Convenience
  • Attacks against User Account Passwords
  • Dictionary, Brute-Force Hybrid Attacks
  • Pre-Computed Hashes
  • Password Complexity Is a Function of
  • Length, size of the symbol set, and ordering -
  • Thus, assuming a random ordering, for each
    additional character in a password, cracking
    becomes exponentially harder

Malware Phishing Scams
  • Mass-Mailing Worms
  • Arrive as email attachments
  • Generally cant be activated unless you open an
    infected attachment
  • Could be embedded in HTML messages
  • Phishing Scams
  • Try very hard to look legitimate
  • International Domain Name spoofing doesnt affect
  • Latest scams direct you to a phony web site to
    enter personal information - or else!
  • Dont open unexpected attachments! or respond to
    unsolicited requests!

Spyware Adware
  • Spyware Tracks Web Browsing Habits
  • Some adware is legitimate
  • You have to read the fine print!
  • Browser Hijacking
  • Youll notice if this happens to you! You keep
    being redirected to the same sites.
  • Be Wary of Free Software
  • That includes security software!
  • Also some alleged antispyware products
  • Think Before You Click!
  • Web links, software downloads, etc.

Top 10 Security Measures
  • Patch Microsoft Windows Automatically
  • New patches 2nd Tuesday of each month
  • Use BigFix Windows Automatic Updates
  • Use Strong Passwords (even better, pass phrases)
    for All User Accounts
  • Use and Properly Maintain Good Antivirus Software
  • Use a Firewall, such as Windows XPs Built-in
    Software Firewall
  • Dont Open Suspicious Email Attachments or
    Respond to Suspicious Requests

Top 10 Security Measures
  • Disable Windows File Printer Sharing
  • So long as youre not using these services
  • Disable in Local Area Connection Properties
  • Disable Unneeded User Accounts
  • Dont Use Automatic Logon (off by default)
  • Less likely to forget your password!
  • http//
  • Use the Screen Lock When You Step Away Shut
    Down When Gone for Over 6 Hours
  • If Possible, Dont Use Internet Explorer
  • Try http//

Questions? Research Tools
  • Malware Research Troubleshooting
  • http//
  • http//
  • http//
  • http//
  • http//
  • http//
  • http//
  • http//
  • http//
  • http//
  • http//
  • http//

Web 2.0
What is Web 2.0
  • transition of the web from a collection of
    websites to a full-fledged computing
    platform.web 2.0 services are expected to
    replace desktop computing applications for many
  • So sayeth Wikipedia

  • Web 1.0
  • Surf the web
  • Click to get results
  • Send email
  • Web 2.0
  • Human interaction in the digital space
  • Conversations taking place
  • Interpersonal networking
  • Personalization and individualism
  • Ability to create, distribute and receive web
  • Ability to participate not just watch from a

  • RSS Really Simple Syndication. Dave Winer is
    credited with being one of the key developers
    behind the concept
  • Does two things
  • You can subscribe to other websites that have RSS
    feeds (syndication)
  • Create content in one place, but display it in
    another place
  • This content can be text, photos, mp3 files,
    video files, etc

With RSS
Without RSS
RSS Aggregator
  • AKA News aggregator, RSS Reader, Feed Reader,
    Fee Aggregator, News Reader.
  • An RSS feed is a page of XML code that lays out
    the content to be distributed for the RSS
  • Examples Newsgator,, My Yahoo,
    Yahoo Email, Googles Gmail, Firefox,
    AmphetaDesk.etc. Huge list of others at

RSS Aggregator
  • AKA web log
  • Entries posted on a regular basis
  • New entries on top
  • Has an RSS feed
  • Differences between blogs site and websites
  • Easy to create new pages
  • Templates automatically add posts in proper
  • Allows searching by title, date, category,
    author, etc
  • Comments on posts

  • What can you do with Blogs?
  • Provide ongoing updates within a team (think of
    the possibilities in a team or agile programming
  • Provide updates about your organization or
  • Provide updates to friend and families.
  • Disadvantage?
  • You better keep it up or remove it, because an
    out of date site screams that you are not on top
    of things.

Blog Resources
  • Free Blogging tools
  • Many more

Tagging, or Folksonomies
  • Categorizing the web
  • Assign freely chosen keywords
  • They tag the item
  • Browsable and searchable
  • Web 2.0 uses tagging

Tagging, or Folksonomies
  • Flickr
  • Digital photo sharing website
  • Photos grouped by submitter, tags, and groups
  • Searching
  • Commenting on each photo
  • RSS of photo feeds user and tags
  • Applications
  • Staff Event or Business function photos
  • Personal Albums to share with friends family
  • Supplement to Blog updates

Tagging, or Folksonomies
Tagging, or Folksonomies
Tagging, or Folksonomies
  • Bookmark Managers
  • AKA Social Bookmarking
  • IE favorites generally tied to a single PC
  • Bookmanagers do the same thing but are accessible
    via the web
  • How it works?
  • Just like marking a favorite/adding a bookmark to
    a site
  • Add tags, description, clipping
  • Others can add comments, ratings
  • Others can subscribe via RSS
  • Searchable

Tagging, or Folksonomies
Tagging, or Folksonomies
  • What can you do with Bookmark Managers?
  • Company, Dept, Team or Project bookmarks.
  • Access your own bookmarks anywhere
  • Find an expert and subscribe
  • Search them
  • Allows you to place the RSS feed on another page,
  • Offers reference web links
  • You can see some of my tech bookmarks at

  • Whats a Wiki?
  • A website that allows anyone to add and edit
  • Great for collaborative authoring
  • Tracks changes so you can revert back to older
    page if needed
  • Monitor changes via RSS
  • Searchable
  • Comments can be allowed

  • WIKI Applications
  • Subject Guides
  • Staff Intranet
  • Project management
  • Committee/Taskforce minutes
  • WIKI Resources
  • http// - free
    wiki software
  • http// - another free (hosted) wiki
  • wikipedia

Instant Messanging (IM)
  • Pretty easy you type, hit enter, they type, hit
    enter, etc.
  • Chat history is tracked
  • Real time communication
  • PCs, cell phones, PDAs all have IM
  • Individual Clients include AOL AIM, MSN
    Messenger, Yahoo! Messenger, IRC, ICQ, Jabber,
    GTalk,, GroupWise Messenger, etc.
  • Multi-Client services Trillian, Gaim, Meebo

Instant Messanger
  • IM Applications
  • Allows for virtual presence of a mobile worker.
    Being virtually there as opposed to physically
  • Can sometimes allow for more direct communication
    with less chit chat.
  • Many also support video conferencing and voice
  • Voice services much cheaper than using toll

  • Web feed of audio that anyone can subscribe to
  • To listen
  • Need to be able to play an MP3 (usually Mp3
  • Need an RSS feed reader or one that specializes
    in RSS enclosures such as iTunes, Juice,
    IpodderX, FireANT.
  • Application
  • News and marketing briefs
  • Great way to keep up to date while on the road by
    synchronizing with MP3 player

  • To Create a Podcast
  • Something to say most important
  • Microphone can be a Radio Shack cheapie
  • Audacity free
  • Place to store the podcast,, etc. free
  • RSS feed that will distribute podcasts free
    (FeedBurner does this)
  • Free, free, free vs Time, Time, Time!

  • AKA video blogging, videologging, vlogging, video
    podcasting, etc
  • Same idea as podcasting, only with video
  • To Watch
  • Need a video player (Windows Media Player) or
    some other portable media devide (eg Archos)
  • Need the RSS feed and a feedreader
  • Even better a videocasting aggregator such as
    mefeedia, fireant, and iTunes

  • Creating a VideoCast
  • Something to say
  • Camcorder cheapies for 30
  • Digital video editing software
  • Windows Movie maker - free
  • Quicktime pro - 30
  • Adobe Video Collection 1000
  • Place to store the videocast free
  • RSS feed that distributes videocasts free
    (feedburner again)
  • Pricey, Takes Time, Is Very Cool.

The Digital Home
HTPCs Multimedia Centers
  • Home Theater and Media Center PCs are allowing
    for centralized distribution of all personal
    media and content. Eg Pictures, Video, TV and
  • It is also allowing for time shifted content and
    personal video recorder (PVR) functionality by
    recording to a built in Hard Drive.
  • Many different options exist from specialized
    PVRs to commercial and open source media center
  • It is the future for home entertainment.

Media Centers
  • The Digital Media Center is designed serve as an
    entertainment, or content distribution hub.
  • Although the focus right now is for the home
    user, the idea of centralized digital content
    distribution is just as viable for a business.
  • Since an increasing amount of content is going
    digital, video, audio, pictures, books, it is
    important to develop an appropraite
    infrastructure to manage this distribution.
  • Best practices for network design should be
    followed in order to ensure there is enough
    bandwidth to support the demand.
  • Although Bandwidth is getting cheaper, dont
    underestimate the cost or the bandwidth required!

HTPC Media Center References
  • MS Windows Media Center http//
  • Media Portal Free Opensource PVR and HTPC
  • http//
  • MythTV Free Opensource Linux PVR and
    HTPC http//
  • BeyondTV Another commercial PVR/MC http//
  • Set top Media Distribution device http//www.dlink
  • Various Articles http//
    1.html http//
    1 http//

HDMI (http//
  • High Definition Multimedia Interface (HDMI) was
    developed to meet the explosive demand for
    high-definition video and audio. HDMI was
    originally developed by Silicon Image, but is now
    in the hands of the HDMI Founders Group.
  • HDMI is a 5Gbps serial, point-to-point interface
    that carries both digital video and digital audio
    data. Note that S-Video, Component Video and DVI
    only deliver the video signal.
  • HDMI supports two-way control communication via
    CEC (Consumer Electronics Control) allowing
    devices to communicate even without a remote
    control. For example, the TV could, in theory,
    automatically notify the DVD player that it is a
    169 aspect ratio display, removing that step
    from the setup.

HDTV References
  • http//
  • http//
  • http//
  • http//
  • http//

Compressing Data
  • Under Sounds and Audio Devices in the control
    panel you can select the compression technologies
  • CODEC refers to Coder/DECoder and can be either
    lossless or lossy compression.
  • More codecs can be retrieved from

MPEG Data Compression Standard
  • MPEG (Motion/Moving Picture Experts Group)
  • Stores full motion video and sound
  • Tracks movement from one frame to the next and
    only stores what changes, rather than compressing
    individual frames
  • A type of lossy compression (Up to 1001 for full
    motion video (30fps)

Current MPEG Standards
  • MPEG-1
  • Used in business and home applications to
    compress images (EG. VCD)
  • MPEG-1 Level 3 (112 to 124)
  • Best known for audio compression (Digital Audio
    Extraction Audio)
  • MPEG-2
  • Used to compress video films (EG. DVD)
  • 720x480, HDTV 1280x720(720p), 1920x1080 (1080p)
  • MPEG-4
  • Used for video transmissions over the Internet.

  • There is a huge choice when it comes to choosing
    an audio format - Mp3, Mp4 (AAC), WMA, Wave and
    Ogg Vorbis, which one is best? It all depends
    upon your needs
  • Lossless (get exactly the same as an Audio CD).
    By default an audio CD is stored as a WAV file,
    however encoders such as Windows Media (WMA),
    Monkeys Audio (APE) and FLAC compress without
    loosing any audio quality think of it as Zip
    for audio.
  • Compressed Audio. Audio can be squashed,
    resulting in a file size much smaller than the
    original, although this is at the expense of
    audio quality, bits get lost unless it is
    compressed in a Lossy audio format Mp3, it the
    most popular by far.

Audio Formats
  • MIDI (musical instrument digital interface)
  • Dictate a specific number of sound samples and
    quality. Specifies pitch, length and volume
  • Have a .mid extension
  • Use data compression due to size of files
  • Used to store most game music

Audio Formats
  • WAV files (.wav)
  • The most basic of all audio formats and stored
    uncompressed in its native form (PCM)
  • When an Audio CD is converted to a wave file the
    resulting wave file is 16 Bit, Stereo with a
    sample frequency of 44.1Khz, this gives 172K
    bytes per second of audio data, or 10MBs per
  • Wave files can use CODECs (stands for COmpression
    DECompression) to be compressed depending upon
    what CODECs are installed.
  • ADPCM is one simple form of compression, it takes
    a 16bit value and creates a 4 bit value by
    calculating the difference between points, so the
    compression is roughly 41.
  • There are even Mp3 CODECs where a wave file can
    be saved as a Wave/Mp3 file. Avoid these types of
    files, as they create confusion if you are after
    a Mp3 file then save it as a proper Mp3 file.

Audio Formats
  • Advance Audio Coding (.aac or .mp4)
  • Advanced Audio Compression (AAC) has been around
    for many years and was designed by Dolby
  • It is more advanced than mp3 and has found
    popularity through mp4.
  • Apple uses AAC with its online music store stored
    as m4a files, although protected
  • A refreshing addition to AAC is HE-AAC, uses
    similar tricks to mp3pro with spectral band
    replication to enhance lower bitrate encodings
    (less than 100 Kbps), although a special HE aware
    decoder is required. AAC has some advanced
    features, such as 48 audio channels and embedded
    data streams. Another use of AAC is with Mpeg-2
    (home cinema). Since AAC Dolby has introduced
    updated AC2 and AC3 standards.

Audio Formats
  • MP3
  • A method to compress audio files that uses MPEG 1
    level 3
  • Sound quality is dependant on the encoder used.
    The best are the Lame Encoder and MP3Pro.
  • Can reduce sound files as low as a 124 ratio
    while still sounding similar to the original by
    removing frequences the human ear cannot hear
    Usually measure in terms of the bits/s eg
    192Kbps, 160Kbps, 128Kbps.
  • While it's compression routines are not the
    best, mp3 really wins out in it's compatibility
    with computers players. Mp3 is the current
    number 1 audio standard, when encoding to mp3
    the Lame encoder is recommended using one of the
    ALT Presets.

Audio Formats
  • MP4
  • Successor to mp3
  • mp4 is basically a container storing many
  • The main audio format would be Advanced Audio
    Compression (AAC).
  • Adding ID tags to mp4 seems to have standardized
    on the Apple iTunes format.
  • Files ending in .m4a are audio content only, .mp4
    can contain both audio and video. See also AAC

Audio Formats
  • Windows Media Audio (.wma)
  • Microsoft's effort, more advanced compression to
    mp3 especially at lower bitrates.
  • WMA v9 added 2 pass VBR, and three new additions
    to the codec - WMA Lossless, WMA Pro and WMA
    Voice. Where as a normal WMA v9 file will play
    fine in a portable player, currently no portable
    players will play any of the new additions.

Audio Formats
  • Ogg Vorbis (.ogg)
  • Ogg Vorbis is a fully Open, non-proprietary,
    patent-and-royalty-free, general-purpose
    compressed audio format for high quality
    (44.1-48.0kHz, 16 bit, polyphonic) audio and
    music at fixed and variable bit rates from 16 to
    128 kbps/channel.
  • Ogg Vorbis is a popular free (as in free from
    patents) encoder, often thought of as having a
    higher quality than Mp3 - most players support
    Ogg through a plug-in.
  • Ogg supports full ID Tagging where track
    information (Artist etc) is imbedded within the
    music file. Ogg support is just appearing on
    portable players.

Audio Formats
  • Monkeys Audio
  • Monkeys Audio is a lossless compressor. When a
    monkeys audio file is played the resulting
    rendition is exactly the same (quality wise) as
    the original. Unlike Mp3 and other lossy
    compression methods, which throw away sound
    information in the name of higher compression
  • The downside to Monkeys approach is that
    compression ratios will only be 41 at best.
    Monkeys Audio uses the flexible APE tagging
    system to imbed track information (Artist etc)
    within the music file

Audio Formats
  • Musepack
  • Thought to be based on mp2, musepack, or mpc, or
    MPEGplus as it is known is apparently a superior
    lossy encoding.
  • Musepack fills the space between lossless and
    encoders designed for lower bit rates such as mp3
    or Ogg. In the 192Kbps range and above, MPC is
    extremely good.

Audio Formats
  • Which Audio Format should you choose depends on
    your needs
  • If you want lossless, then Monkeys Audio (APE) or
    FLAC are good formats. However you need plugins
    for your media player. Of course if you are using
    windows media player then Windows Media Audio
    (WMA) is also a good option. (For IPOD/Itunes
    users I believe there is also an AAC lossless
    format using the Applie Lossless Encoder)
  • If you want to go with the flow choose Mp3, it
    the most popular by far. Mp3 is the undisputed
    king. Althoug its compression routines are not
    the best, mp3 really wins out in it's
    compatibility with computers players. Many
    media players will convert to and from MP3 for
    you, but a good stand alone mp3 codec is the Lame
    (http// encoder
  • If you are using limited memory on a portable mp3
    player (64Kbps - 96Kbps) Windows Media Audio
    (WMA) is a good choice.

Audio Formats
  • Best Audio Format (cont.)
  • If your portable mp3 player has more room such as
    the iPod try mp4, or Ogg Vorbis
  • Want the highest quality lossy? (160Kbps -
    320Kbps) Musepack (http// is
    the best sounding lossy, although PC support
  • A good public all rounder (80Kbps - 160Kbps) is
    Ogg Vorbis, but check the compatibility if
    transferring to a portable player.

Audio Formats
  • Refer to http//
    ide-formats.htm for information on audio formats

Video Compression
  • Lossless compression
  • Compression that doesn't sacrifice any video or
    audio quality, no data is lost. Very high
    quality playback, but not great space savings.
    Video files are still very large. Some popular
    lossless codecs are HuffYUV, Lossless MJPEG, and
  • Lossy compression
  • Just like it sounds, lossy compression "loses"
    some of the original audio and video information.
    That loss of information is what causes video
    streams to occasionally look blocky or pixelated.
    The major benefit of lossy compression is that
    it reduces video file sizes dramatically. Some
    popular lossy codecs are MPEG1, MPEG2, MPEG4.

Video Compression
  • Intra-frame vs Inter-frame.
  • Some compression algorithms, such as Motion JPEG
    (MJPEG) compress each frame individually. This
    is called intra-frame compression because it only
    relies on the information within each frame for
    compression. More advanced compression, such as
    the MPEG family of codecs rely on the changes in
    information between frames, counting on the fact
    that most frames will have something in common
    with the one right before and right after it.
    This is called inter-frame compression.
  • In inter-frame compression there will be
    keyframes spaced throughout the sequence of
    compressed frames. Keyframes are frames that are
    compressed like an intra-frame codec, so they
    don't rely on surrounding frames for
    decompression. The more keyframes that are
    included in a video stream, the higher the
    playback quality tends to be, but they also
    increase file size significantly.

Software Developers
  • So what is the potential for software developers
    in all these applications and services?

References Web Sites
  • Refer to my bookmarks at