Upload
marcus-wilkerson
View
215
Download
0
Embed Size (px)
Citation preview
Media and Medium
Chapter 10
Learning Objectives
Identify and discuss the various types of transmission media
Explain how to physically protect transmission media adequately
Identify and discuss the various types of storage media
Know how to lessen the risk of catastrophic loss of information
continued…
Learning Objectives
Understand the various ways to encrypt data
Properly maintain or destroy stored data
Transmission Media
Coaxial cable Twisted pair copper cable
Shielded Unshielded
Fiber-optic cable Wireless connections
Coaxial Cable
Hollow outer cylinder surrounds a single inner wire conductor
Coaxial Cable
More expensive than traditional telephone wiring Less prone to interference Typically carries larger amounts of data Easily spliced; allows unauthorized users access
to the network Two types (not interchangeable)
50-ohm 75-ohm
50-Ohm Coaxial Cable
Uses unmodulated signal over a single channel
Two standards 10Base2 (ThinNet) 10Base5 (ThickNet)
50-Ohm Coaxial Cable
Advantages Simple to implement and widely available Low cost alternative that provides relatively
high rates of data transmission Disadvantages
Can only carry data and voice Limited in distance it can transmit signals
10Base2 (ThinNet)
Uses a thin coaxial cable in an Ethernet environment
Capable of covering up to 180 meters Allows daisy chaining Not highly susceptible to noise interference Transmits at 10 Mbps Can support up to 30 nodes per segment
10Base5 (ThickNet)
Primarily used as a backbone in an office LAN environment
Often connects wiring closets Can transmit data at speeds up to 10 Mbps Covers distances up to 500 meters Can accommodate up to 100 nodes per
segment Rigid and difficult to work with
75-ohm Coaxial Cable
For analog signaling and high-speed digital signaling
75-ohm Coaxial Cable
Advantages Allows for data, voice, and video capabilities Can cover greater distances and offers more
bandwidth Disadvantages
Requires hardware to connect via modems More difficult to maintain
Twisted Pair Copper Cable
Individual copper wires are twisted together to prevent cross talk between pairs and to reduce effects of EMI and RFI
Inexpensive alternative to coaxial cable, but cannot support the same distances
Long been used by telephone companies Types
Unshielded twisted pair (UTP) Shielded twisted pair (STP)
Unshielded Twisted Pair (UTP)
Most common medium for both voice and data
Currently supports up to 1 Gbps protocols
Shielded Twisted Pair (STP)
Extra foil shield wrapped between copper pairs provides additional insulation from EMI
Used extensively in LAN wiring
Shielded Twisted Pair (STP)
Twisted Pair Categories
Category 3 (CAT 3) Category 5 (CAT 5) Category 6 (CAT 6)
Twisted Pair CAT 3
For voice and data transmission
Twisted Pair CAT 5
Supports fast Ethernet Utilizes an 8-pin configuration that can be
modified for use as a crossover cable, straight-through cable, or customized cable
Twisted Pair CAT 6
Supports Gigabit Ethernet Offers backwards compatibility Uses an 8-pin configuration
Twisted Pair
Connects to hardware using an RJ-45 connector
Fiber-Optic Cable
Glass core encased in plastic outer covering
Smaller, lighter, more fragile and susceptible to damage than coaxial or twisted pair cable
Carries light
Fiber-Optic Cable
Fiber-Optic Cable
Advantages Capable of transmitting more data much
further than other wiring types Completely immune to effects of EMI Nearly impossible to splice without detection
Disadvantages Expensive Difficult to install and manipulate
Comparison ofWired Transmission Media
Media Advantages Disadvantages
Coaxial cable High bandwidth
Long distances
EMI immunity
Physical dimensions (difficult to work with)
Easily tapped
Twisted pair copper cable
Inexpensive
Widely used
Easy to add nodes
Most sensitive to EMI
Supports short distances
Limited bandwidth capabilities
Easily tapped
Fiber-optic cable
Very high bandwidth
EMI immunity
Long distances
High security
Small size
Difficult to implement
Expensive
Fragile
Unguided Transmission
Uses various technologies (microwave, radio and infrared) to receive and transmit through the air
Vulnerable to security breaches in which unauthorized users intercept data flow
Difficult to secure; unguided connections cannot be physically contained easily
Securing Transmission Media
Common attacks on data flow include interception and interruption of traffic
Use lock and key Install closed circuit security cameras Use equipment that limits or eliminates
signal leaks Use dry methods for fire extinguishing
continued…
Securing Transmission Media
Deploy an uninterruptible power supply Implement a redundant network Utilize a VPN or other encryption
technology when using wireless LANs Map out cabling and deploy fiber optics in
unsecured areas
Storage Media
Provides a way to hold data at rest Hard disk drive
Developed by IBM in 1970s Ubiquitous
Removable storage media Magnetic Optical Solid-state
Magnetic Storage Media
Coated with iron oxide When data is recorded:
Electromagnet inside disk drive rearranges the iron oxide particles into a series of patterns that represent 0s and 1s
When data is retrieved: Reading disk drive uses a magnetic field to read the
pattern Pattern is translated into data that is sent to computer
in binary form
Types of Magnetic Storage Media
Floppy Disk
3.5 inch, high density 1.44 MB capacity Circular magnetic piece of plastic inside a
rigid plastic case
Zip Disk
High-capacity floppy disk developed by Iomega Corporation
100 MB and 250 MB capacity Relatively inexpensive and durable Ideal for transporting larger multimedia
files Can be used for backup
Optical Storage Media
Light and reflection transmit data
Most common: CD Plastic disc covered by
a layer of aluminum and a layer of acrylic
Typically can store 700 MB of data
Commonly used to store multimedia
Compact Disc
Data is recorded by creating very small bumps in the aluminum layer on long tiny tracks
Data is read by a laser beam, detected by an optoelectronic sensor, and the pattern translated into bits and sent to the computer
CD-ROMs
Most common type of CD Material can be written or recorded to the
disc only once Hold prerecorded materials to be used on a
computer (eg, software, graphic images, short video clips, audio)
Compact Disc-Recordable (CD-R)
User records data onto surface of a blank disc Has layer of light-sensitive dye on top of layer of
reflective gold High-powered laser beam burns data on the disc
Changes color of light-sensitive dye by pulsing in patterns
Write once, read many (WORM) type of media Next step: compact disc-rewritable (CD-RW)
Digital Versatile Disc (DVD)
Can store much more data than a CD Tracks are thinner and closer to each other Readable on both sides of the disc
Made out of plastic with a layer of gold, covered by a thin layer of clear polymer
Used to store full-length feature films
Solid-State Storage Media
Uses a microchip upon which data is recorded directly in digital form
Reliable and durable; no moving parts Very small, yet can contain up to 192 MB
of memory “Flash memory”
Used primarily in digital cameras, digital video cameras, digital audio recorders
Solid-State Storage Media
CompactFlash card SmartMedia card Memory Sticks
CompactFlash Card
Stores up to 1 GB High data transfer rate Resistant to extreme weather conditions
SmartMedia Card
Used in digital still cameras, MP3 recorders, newer printing devices
Stores up to 64 MB of data Less expensive than CompactFlash cards High data transfer rate Resistant to extreme weather conditions
Memory Stick
Holds up to 128 MB of data Commonly used with digital still cameras,
digital music players (MP3), digital voice recorders
High data transfer rate Resistance to extreme temperatures High storage capacity
Secure Digital/Multimedia Cards
Commonly used in MP3 players and digital cameras
Developed to help enforce copyright protections for publishers of music and images
Range in size from 4 MB to 128 MB
Avoiding Catastrophic Loss
Make backup copies of sensitive information and store them at a separate, secure location, preferably in a fire safe
Use a type of media that is less likely to be corrupted or damaged (ie, solid-state)
Encryption
Implement a thorough encryption policy to guarantee that sensitive information does not fall into the wrong hands
Educate the entire organization about the importance of safeguarding sensitive data
Storing Media
Have a policy that tracks content and location of each disk
Mark each medium using a standardized naming scheme
Store copies in a secure location
Destruction of Media
Physically destroy the media Erase the data
Chapter Summary
Transmission media Storage media Impact of different forms of transmission
media and storage media on information security