5 types of network:

• Internet 
• Telcos (Telecommunication service providers)
• Company network (Intranet)
• Universal network
• Home network (Provides communication among devices within the close area of a house)

4 Keys Elements of the Internet:

• Host
• IP Address (Unique for every device)
• Host name 
• Domain Name System (DNS)

Network standards are needed to:

• Allow hardware and software from different vendors to interoperate.
• For two or more equipment that are used for the application interpret and intergrated information stream in the same way.
• Ensure both communicating parties utilize the same standards for detecting information stream.

Types of computer network:

•  LAN - Local (restricted to a single site) -Wireless (WLAN)
• MAN - Metropolitan (banks)
• WAN - Wide (entire globe)
• PAN - Personal

The network topologies:

• Mesh (Best)
• Star
• Bus
• Tree
• Ring

Bandwidth(server farm):

Throughput:

Data speed ↓ Factors :

The purpose of the physical layer:

FOUR (4) physical layer elements required in order to deliver the frame across the network:

• The physical media and associated connectors 
• A representation of bits on the media. 
• Encoding of data and control information.
• Generate signal that represent the '1' and '0' on the media.

THREE (3) three basic forms of network media on which data is represented:

• Copper cable media (Using electric signal)
• Fibre optic (Using light pulse signal)
• Wireless media (Using microwave )

100Base-T

THREE (3) types of coaxial cable:

• RG-6 – Cable TV
• RG58/U – Thin Ethernet
• RG8 – Thick Ethernet

Advantages of coaxial cable:

• Requires fewer repeaters than twisted pair
• Less expensive than fiber
• It has been used for many years for many types of data communication, including cable television

Disadvantages of coxial cable:

• More expensive and more difficult to install than twisted pair
• Needs more room in wiring ducts than twisted pair

TWO (2) types of twisted pair cable:

• Shielded
•  Unshielded

TWO (2) disadvantages of Shielded twisted-pair cable (STP):

• More expensive and difficult to install than UTP.
• Needs to be grounded at both ends

THREE (3) types of cabling for UTP:

• Straight-through
• Cross-over
• Rollover

The process to make a cable:

• Cut a Length of Cable
• Strip off the Jacket
• Separate the Wires
• Untwist the Wires
• Organize and Flatten Wires
• Clip the Wires
• Insert Wires into RJ-45 Plug
• Push the Wires In
• Inspect the Color Code
• CAT5 Termination (568A)
• Crimp Down the Wires
• Inspect Both Ends
• Test the Quality of Cable

• Fiber optic is primarily installed as the backbone of a network (i.e. between switches and routers).
• The range of distance of fibre optic in LAN installation is 200 meters to 2 km.
• The core building of fibre optic is glass fibre.
• The medium of travel for data in fibre optic cable is light.
• Single-mode fibre carries single frequency of light while multimode fibre carries many frequencies of light over a single or many fibres to transmit data.
• The refraction during data transmission would cause the loss of part of the light energy of the ray.
• The glass shield around the core is cladding.

• Every fiber-optic cable used for networking consists of two glass fibers encased in separate sheaths:

• - One fiber carries transmitted data from device A to device B. 

• - The second fiber carries data from device B to device A.

• - This provides a full-duplex communication link.

• The type of connector most commonly used with multimode fibre is Subscriber Connector (SC connector).

FOUR (4) factors of a standard:

• Access point - network nodes connected directly to a wired or wireless local area network. 
• PCMCIA wireless card is built for portable devices.
• As a central hub, the range of an access point most commonly, the range will be from 91.44 to 152.4 meters (300 to 500 feet).
• PCI adapter is used inside the desktops/PCs to gain access to the wireless network.

TWO (2) topologies specific for the wireless network:

• BLOB (Binary Large Object)

3 code designs:

• Morse (during war)

• ASCII (read MSB first)
• EBCDIC

Advantages of digital audio:

• Quality better
• Less noise
• Louder
• Easy to transfer
• Editable

Disadvantages of digital audio:

• Quantization error
• Sampling rate>1%, Noise

• Vector

• Bitmap

• Hackers
• Criminals
• Cyberterrorism
• Employees

Types of attacks:

• Malicious content
• Denial of Service (DoS)
• Scanning attack

Security system:

• Confidentiality (Access)
• Integrity (Edit)
• Availability (only available to authorized people)
• Authenticity (Verify)

Types of security system:

• Secure comunication system
• Attack preventation system

• Network Security Policy

What is NSP?

Purposes of NSP

• Provide a baseline
• Inform users, staff and employees
• Specify mechanisms for security

Users can be organized into 2 audiences:

• Internal audience

• External audience

3 main reasons:

• Large data volume (Size of MM elements)
• Relatively slow storage (expensive)
• Bandwidth limitation

Compression:

Codec: 

Compression file

Determine the assets that need the protection of a security policy by asking question:-

• What do you have that others want?
• What processes, data, information system are critical to you, your company, or your organization?
• What would stop your company ? organization from doing business or fulfilling its mission?

Purpose of the security policy:

• To inform users, staff, and managers
• To specify mechanisms for security
• To provide a baseline

Why need Security policy?

• Protects people and information
• Sets the rules for expected behavior
• Authorizes staff to monitor, probe, and investigate
• Defines the consequences of violations

Security Policy Components

• Governing Policy
• Technical Policy
• End-User Policy

3 aspect:

• Network performance
• Quality of Service (QS)
• Multimedia Transmission

Network Performance Parameter:

•  Throughput

•  Networking delay

•  Delay variable
•  Error rate

• Email containing types of data other than text is called multimedia email. (eg. graphics, audio, video)

MIME (Multimedia/ Multipurpose Internet Mail Extension)

• MIME is a standard developed as a set of extensions to SMTP.

SMTP (Simple Mail Trasfer Protocol)

• MIME Problem:

• Streaming Problem:

• System that use internet technology to deliver TV program.

3 types of IPTV:

•  Video On Demand (VOD)
•  Time-shifted IPTV
•  Live IPTV or IP simulcasting

• Transmission of live video between 2 or more communicating sites.

Aspect of VC:

•    Full duplex
•    Half duplex
•    Simplex

• Taking the media and broadcasting it in real time over the internet called live webcast

Benefit of webcast:

• Increased revenue
• Connect with your audience
• Smaller environmental footprint
• Quality of Output
• Convenience
• Richer content
• Broadcasting range

Web Services benefit:

• Easier to communicate between different app
• Easier reuse existing web services instead of writing new ones
• Easier to distribute information to more consumers
• Rapid development