Transcript Security+ Guide to Network Security Fundamentals

Media and Medium
Chapter 10
Learning Objectives
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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
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Understand the various ways to encrypt
data
Properly maintain or destroy stored data
Transmission Media
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Coaxial cable
Twisted pair copper cable
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Shielded
Unshielded
Fiber-optic cable
Wireless connections
Coaxial Cable
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Hollow outer cylinder surrounds a single
inner wire conductor
Coaxial Cable
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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)
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50-ohm
75-ohm
50-Ohm Coaxial Cable
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Uses unmodulated signal over a single
channel
Two standards
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10Base2 (ThinNet)
10Base5 (ThickNet)
50-Ohm Coaxial Cable
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Advantages
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Simple to implement and widely available
Low cost alternative that provides relatively
high rates of data transmission
Disadvantages
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Can only carry data and voice
Limited in distance it can transmit signals
10Base2 (ThinNet)
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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)
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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
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For analog signaling and high-speed digital
signaling
75-ohm Coaxial Cable
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Advantages
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Allows for data, voice, and video capabilities
Can cover greater distances and offers more
bandwidth
Disadvantages
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Requires hardware to connect via modems
More difficult to maintain
Twisted Pair Copper Cable
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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
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Unshielded twisted pair (UTP)
Shielded twisted pair (STP)
Unshielded Twisted Pair (UTP)
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Most common medium for both voice and
data
Currently supports up to 1 Gbps protocols
Shielded Twisted Pair (STP)
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Extra foil shield wrapped between copper
pairs provides additional insulation from
EMI
Used extensively in LAN wiring
Shielded Twisted Pair (STP)
Twisted Pair Categories
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Category 3 (CAT 3)
Category 5 (CAT 5)
Category 6 (CAT 6)
Twisted Pair CAT 3
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For voice and data transmission
Twisted Pair CAT 5
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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
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Supports Gigabit Ethernet
Offers backwards compatibility
Uses an 8-pin configuration
Twisted Pair
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Connects to hardware using an RJ-45
connector
Fiber-Optic Cable
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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
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Advantages
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Capable of transmitting more data much
further than other wiring types
Completely immune to effects of EMI
Nearly impossible to splice without detection
Disadvantages
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Expensive
Difficult to install and manipulate
Comparison of
Wired 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
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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
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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
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Securing Transmission Media
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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
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Provides a way to hold data at rest
Hard disk drive
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Developed by IBM in 1970s
Ubiquitous
Removable storage media
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Magnetic
Optical
Solid-state
Magnetic Storage Media
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Coated with iron oxide
When data is recorded:
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Electromagnet inside disk drive rearranges the iron
oxide particles into a series of patterns that represent
0s and 1s
When data is retrieved:
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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
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3.5 inch, high density
1.44 MB capacity
Circular magnetic piece of plastic inside a
rigid plastic case
Zip Disk
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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
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Light and reflection
transmit data
Most common: CD
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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
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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
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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)
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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
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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)
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Can store much more data than a CD
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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
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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”
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Used primarily in digital cameras, digital
video cameras, digital audio recorders
Solid-State Storage Media
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CompactFlash card
SmartMedia card
Memory Sticks
CompactFlash Card
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Stores up to 1 GB
High data transfer rate
Resistant to extreme weather conditions
SmartMedia Card
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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
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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
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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
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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
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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
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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
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Physically destroy the media
Erase the data
Chapter Summary
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Transmission media
Storage media
Impact of different forms of transmission
media and storage media on information
security