Transcript Intro to Networking

Intro to Networking
Philip Ashman
Asst. Prof. Okanagan College
Dept of Network & Telecommunications
Engineering Technologies
1
Objective
• A quick note of reference. The information contained in
this presentation is all information that has been and
can be readily found on the Internet.
• 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!
3
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
4
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
5
Computer Networking Models
• Models, or protocol stacks, are organized into layers.
This organizes the process into modules simliar to
breaking programming code into subroutines
OSI-7 Layer Model
DOD 3-Layer Model
Simplified 4/5-layer Model
Application
Application
7
Application
6
Presentation
5
Session
4
Transport
3
Network
2
Data
Local Network
Data
1
Physical
(LAN)
Physical
Protocol
Transport
Newtork
OSI (Open Systems Interconnection) mnemonic
“All People Seem To Need Data Processing”
If you ever take a test on networking, you’ll have to now this, otherwise it is best to
stick to the simplified model.
6
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 “T”wisted 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…
7
Intro to Networking
• Depending on one’s 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
Client/Server
– Based on topology (connectivity): Bus, Star, Ring
8
Transmission Media
Transmission Media
• Two main categories:
1. Guided
• Twisted-Pair cables:
 Unshielded Twisted-Pair (UTP) cables
 Shielded Twisted-Pair (STP) cables
• Coaxial cables
• Fiber-optic cables
2. UnGuided
• Wireless transmission, e.g. radio, microwave, infrared,
sound, sonar
11
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 it’s original amplitude and cancel out
the interference.
14
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
Plastic Cover
4 Pairs
Insulator
Metal
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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
16
Categories of UTP Cables
• EIA classifies UTP cables according to the quality
Categories 1,2,4 used to exist, but you can’t buy them
any more:
Category 3
At least 3 twists per foot, for up to 10 Mbps (common
in phone networks in residential buildings)
Category 5 (or 5e)
Up to 100 Mbps (common for networks targeted for
high-speed data communications)
Category 6
More twists than Cat 5, up to 1 Gbps and uses 23
Gauge wire. Also rated up to 10Gbps for 35m.
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Coaxial Cables
• In general, coaxial cables, or coax, carry signals of
higher freq (100KHz–500MHz) than UTP cables
• Outer metallic wrapping serves both as a shield against
noise and as the second conductor that completes the
circuit
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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 medium
• The critical angle is the point at which the light is reflected
back.
• Beyond the critical angle  total internal reflection
19
Fiber-Optic Cables
• An optical fiber consists of a glass core (denser material) and
a plastic cladding (less dense material)
• 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.
20
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)
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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 copper
– Installation/maintenance
Any crack in the core will degrade the signal, and all
connections must be perfectly aligned
22
Wireless
Protocol
Release Date
Legacy
1997
802.11a
Op. Frequency
Data Rate (Typ)
Data Rate (Max)
Range (Indoor)
2.4 -2.5 GHz
1 Mbit/s
2 Mbit/s
?
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 freq.)
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Wireless
• 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.
24
Wireless Security
• When setting up your wireless access point learn
how to log in to it and change the default settings!
–
–
–
–
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.
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Local Area Network (LAN)
&
Wide Area Network (WAN)
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 organization
• Examples:
• Network inside a Student Computer Lab
• Network inside Okanagan College
• Network inside your home
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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
Your home
• Examples:
• Inter/Intra-City Connections
• Internet
WAN
Canada
Office
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WAN
• Example WAN technologies:
• ISDN – Integrated Service Digital Network
• BW: Basic Rate: 192 Kbps Primary rate: 1.544Mbps
• T-Carriers ― basically digital phone lines
• BW: T1: 1.544Mbps T3: 28T1=approx 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
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Broadband Cable Network
TV
PC
Coaxial
Cable
The connection is shared by a
number of subscribers, hence
may raise performance and
security problems
Cable
Drop
Cable company
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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
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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 Network
• 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.
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Telco Network
Each connection is shared by
a number of subscribers,
hence may raise performance
and security problems
Copper
Cable
Home
Business
Local
Telco
Office
Telco company
35
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
36
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.
37
Peer to Peer Networks
Vs
Client Server Networks
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
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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
41
Clients-Server Networks
• Network Clients (Workstation)
• Computers that request network resources or services
• 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
42
Client-Server Networks
• Advantages of client/server networks
• Facilitate resource sharing – centrally administrate
and control
• Facilitate system backup and improve fault tolerance
• Enhance security – only administrator can have
access to Server
• Support more users – difficult to achieve with peer-topeer 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
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Network Topology
• 3 basic types?
Bus Topology
Ring Topology
Star Topology
Core
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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 point
• 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
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computers may send message at the same time
Network Topology
Bus Topology
Coaxial
cable
Star Topology
BNC T-Connector
Network Card
46
Topology
Ring Topology
T T
Ack
• Every computer serves as
a repeater to boost signals
T data
• Uses Token passing to send
data, where only the computer
T
who gets the token can send
T Ack
data
• Disadvantages
• Difficult to add computers
T
• More expensive
• If one computer fails, whole network fails
T
T
data
T
T
data
Ack
T
Ack
47
Protocol Basics
Ethernet Addressing (Layer 2)
• Since there can be many users on an ethernet network,
everyone has to have their own unique address.
• This is called the Media Access Control (or MAC) address,
or sometimes ethernet address, physical address, adaptor
address, hardware addres, etc.
• It’s 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 00:30:65:83:fc:0a or 0030.6583.fc0a or
003065:83fc0a 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 inteface’s own. Like a
car’s VIN. See http://coffer.com/mac_find/ to look up some
vendor codes.
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Hubs vs. Switches
• Hubs
– Shared media devices
– Everyone sees everyone’s 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.
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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.
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Finding your Ethernet Address
• On Windows 95/98, from the “run” menu type
“winipcfg”
• 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
https://radon.bc.tac.net/cgi-bin/oca2.cgi)
53
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 device.
• Although IP is by far the most predominant protocol in
use, there are others such as AppleTalk, Netware, etc.)
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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! It’s so handy that most everyone
uses it on all their networks big and small.
• Very Scalable allowing it to support the ever-expanding
Internet.
55
IP Addressing
• IP addresses consists of 4 “octets” such as:
171.64.20.23
• Each “octet” consists of numbers between 0 and 255
(or 00 and FF in hex! Don’t ask why ethernet is in hex
but IP isn’t, 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!)
56
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://www.arin.net)
• 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 names.
• Your computer, however, needs a number, so the
Domain Name System (DNS) exists to make everyone
happy.
57
DNS
• A name, such as “technologies.okanagan.bc.ca” 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 college’s network. The label Technologies is
a specific machine on this network.
• If you want the number for a host name within
okanagan.bc.ca you’ll 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
58
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 it’s way.
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Routers
• A router’s 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://www.warriorsofthe.net/)
60
DHCP
• 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 network.
• However this router is also a DHCP client since it gets
it’s external IP information automatically from the
upstream services provider (Usually Shaw or Telus)
61
Troubleshooting
• You can’t 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 doesn’t always indicate a problem with
the host or network, but it’s 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.
62
Troubleshooting
Traceroute
– Traceroute asks all routers along the path between you
and the destination host if they’d 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 doesn’t always indicate a problem with
the host or network, but again it’s 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.
63
Security Tips
Topics
• 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
65
What’s the Threat?
• Viruses, Hackers and Worms - Oh, My!
– Purists reserve the term “hacker” for ace programmers, not
“attackers”
http://catb.org/~esr/jargon/html/H/hacker.html
• “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: It’s a Jungle Out There!
– And an oz. of protection is worth a lb. of cure
66
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 PC’s configuration
– You understand that changing security-related settings
can impair functionality: You might have to undo some
changes
67
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
68
Out of the Box
• You Just Got a New PC: Now What?
– It’s not securely configured by default
– Security software is probably missing
– The “survival time” of an unpatched PC
– See http://isc.sans.org/survivalhistory.php
• First: Don’t 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
69
So You’re on the Internet…
• Go to http://windowsupdate.microsoft.com
– 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, Spybot)
70
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
72
Malware & Phishing Scams
• Mass-Mailing Worms
– Arrive as email attachments
– Generally can’t 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 doesn’t affect IE
– Latest scams direct you to a phony web site to enter
personal information - or else!
– Don’t open unexpected attachments! or respond to
unsolicited requests!
73
Spyware & Adware
• Spyware Tracks Web Browsing Habits
– Some “adware” is “legitimate”
– You have to read the fine print!
• Browser Hijacking
– You’ll 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.
74
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 XP’s Built-in Software
Firewall
• Don’t Open Suspicious Email Attachments or Respond to
Suspicious Requests
75
Top 10 Security Measures
• Disable Windows File & Printer Sharing
– So long as you’re not using these services
– Disable in Local Area Connection Properties
• Disable Unneeded User Accounts
• Don’t Use Automatic Logon (off by default)
– Less likely to forget your password!
http://support.microsoft.com/default.aspx?scid=kb;en-us;315231
• Use the Screen Lock When You Step Away & Shut Down
When Gone for Over 6 Hours
• If Possible, Don’t Use Internet Explorer:
– Try http://www.mozilla.org/firefox
76
Questions? Research Tools
• Malware Research & Troubleshooting:
– http://support.microsoft.com/kb/129972
– http://www.google.com
– http://www.sarc.com
– http://www.mcafeesecurity.com/us/security/home.asp
– http://housecall.trendmicro.com/
– http://en.wikipedia.org/wiki/Computer_virus
– http://www.educause.edu/Browse/645?PARENT_ID=741
– http://www.spywareinfo.com/
– http://support.microsoft.com
– http://www.microsoft.com/technet
– http://www.cert.org/
– http://www.cisecurity.org/
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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 puposes”
So sayeth Wikipedia
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Interactivity
• 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 content
– Ability to participate – not just watch from a distance
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RSS
• RSS = Really Simple Syndication. Dave Winer is
credited with being one of the key developers behind
the concept
• Does two things:
1. You can subscribe to other websites that have RSS
feeds (syndication)
2. Create content in one place, but display it in another
place
• This content can be text, photos, mp3 files, video files,
etc…
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RSS
Without RSS
With RSS
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RSS
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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 aggregator.
• Examples: Newsgator, Bloglines.com, My Yahoo,
Yahoo Email, Google’s Gmail, Firefox,
AmphetaDesk….etc.
Huge list of others at
http://en.wikipedia.org/wiki/List_of_news_aggregators
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RSS Aggregator
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Blogs
• 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 places
– Allows searching by title, date, category, author, etc
– Comments on posts
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Blogs
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Blogs
• What can you do with Blogs?
– Provide ongoing updates within a team (think of the
possibilities in a team or agile programming
environment)
– Provide updates about your organization or department
– 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.
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Blog Resources
• Free Blogging tools:
– Blogger.com
– Livejournal.com
– Wordpress.com
– Many more…
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Tagging, or Folksonomies
• Categorizing the web
• Assign freely chosen keywords
• They “tag” the item
• Browsable and searchable
• Web 2.0 uses tagging
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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
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Tagging, or Folksonomies
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Tagging, or Folksonomies
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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
– Del.icio.us, www.furl.net, www.blinklist.com
• 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
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Tagging, or Folksonomies
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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
– Del.icio.us:
• Allows you to place the RSS feed on another page,
• Offers reference web links
• You can see some of my tech bookmarks at
http://del.icio.us/philashman
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WIKI
• What’s a Wiki?
– A website that allows anyone to add and edit content
– 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
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WIKI
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WIKI
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WIKI
WIKI Applications
– Subject Guides
– Staff Intranet
– Project management
– Committee/Taskforce minutes
WIKI Resources
– http://www.mediawiki.org/wiki/MediaWiki - free wiki
software
– http://pbwiki.com/ - another free (hosted) wiki
– www.wikipedia.org – wikipedia
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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 (webbased)
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Instant Messanger
• IM Applications
– Allows for virtual ‘presence’ of a mobile worker. Being
‘virtually’ there as opposed to physically there.
– Can sometimes allow for more direct communication
with less chit chat.
– Many also support video conferencing and voice
services.
– Voice services much cheaper than using toll lines.
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Podcasting
• Web feed of audio that anyone can subscribe to
To listen:
– Need to be able to play an MP3 (usually Mp3 player)
– 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
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Podcasting
To Create a Podcast
– Something to say – most important
– Microphone = can be a Radio Shack cheapie
– Audacity = free
– Place to store the podcast – archive.org, ourmedia.com,
etc. = free
– RSS feed that will distribute podcasts = free
(FeedBurner does this)
– Free, free, free vs Time, Time, Time!
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VideoCasting
• 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
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VideoCasting
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 – archive.org = free
– RSS feed that distributes videocasts = free (feedburner
again)
– Pricey, Takes Time, Is Very Cool.
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The Digital Home
HTPC’s & Multimedia
Centers
• Home Theater and Media Center
PC’s are allowing for centralized
distribution of all personal media
and content. Eg: Pictures, Video, TV
and Audio.
• 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 PVR’s to commercial
and open source media center
softwarere.
• It is the future for home
entertainment.
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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, don’t
underestimate the cost or the bandwidth required!
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HTPC & Media Center
References
MS Windows Media Center
http://www.microsoft.com/windowsxp/mediacenter/default.mspx
Media Portal – Free Opensource PVR and HTPC
http://mediaportal.sourceforge.net/
MythTV – Free Opensource Linux PVR and HTPC
http://www.mythtv.org/
BeyondTV – Another commercial PVR/MC
http://www.snapstream.com
Set top Media Distribution device
http://www.dlink.com/products/?sec=3&pid=387
Various Articles
http://www.2cpu.com/articles/113_1.html
http://www.htpcnews.com/main.php?id=guides1
http://www.tivo.com/0.0.asp
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HDMI
(http://www.hdmi.org)
• 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 16:9 aspect ratio display, removing that step from
the setup.
HDMI to HDMI
HDMI to DVI
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HDTV References
• http://www.avsforum.com/
• http://www.hdmi.org
• http://www.htguys.com/
• http://www.hdtvmagazine.com/articles/2005/12/lcos.ph
p?page=1
• http://www.hdbeat.com
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Compressing Data
• Under Sounds and Audio Devices in the control panel
you can select the compression technologies
supported.
• CODEC refers to Coder/DECoder and can be either
lossless or lossy compression.
• More codecs can be retrieved from
http://www.afreecodec.com
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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 100:1 for full motion
video (30fps)
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Current MPEG Standards
MPEG-1
– Used in business and home applications to compress images
(EG. VCD)
MPEG-1 Level 3 (1:12 to 1:24)
– 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.
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Compression
• 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.
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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 1:24 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.
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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://www.mp3dev.org/) encoder
– If you are using limited memory on a portable mp3 player
(64Kbps - 96Kbps) Windows Media Audio (WMA) is a
good choice.
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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://www.musepack.net) is the best
sounding lossy, although PC support only.
– A good public all rounder (80Kbps - 160Kbps) is Ogg
Vorbis, but check the compatibility if transferring to a
portable player.
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Audio Formats
• Refer to http://www.dbpoweramp.com/spoons-audioguide-formats.htm for information on audio formats
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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 Alparysoft.
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.
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Conclusion!
Software Developers
• So what is the potential for software developers in all
these applications and services?
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References & Web Sites
• Refer to my Del.icio.us bookmarks at
http;//del.icio.us/philashman
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