Media and Cable Distribution Flashcards
Media
Material used to transmit data over the network
Copper Media Types
▪ Three categories:
● Copper
● Fiber optic
● Wireless
Coaxial Cable (COAX)
Inner
● Insulated conductor or center wire passes data
▪ Outer
● Braided metal shield used to help shield and protect the data
transmission
● Provides EMI resistance due to shielding
Coaxial Cables
RG-6
● Commonly used by local cable companies to connect individual
homes
▪ RG-59
● Typically used to carry composite video between two nearby
devices, such as from a cable box to the television
Coaxial connectors
▪ F-connector
● Typically used for cable TV and cable modem connections
▪ BNC
● Termed Bayonet Neill-Concelman or British Naval Connector
● Was used for 10BASE2 Ethernet networks
Twinaxial cable
Similar to coaxial cable but uses two inner conductors to carry the data
instead of just one
Serial cable
Usually have a series of straight copper wires inside a single cable or
plastic jacket
▪ DB-9 or DB-25 (RS-232)
● 9-pin or 25-pin D-subminiature
● Used for asynchronous serial communications and connecting to
an external modem
Twisted pair cables
▪ Most popular physical LAN media type
▪ Eight individually insulated strands of copper wire inside each cable
▪ Each pair twisted together to reduce EMI
● Tighter twists = less EMI
▪ Types:
● Unshielded Twisted Pair (UTP)
● Shielded Twisted Pair (STP)
Unshielded twisted pair (UTP)
▪ Number of twists determines how much EMI can be blocked
● CAT 6 has more twists per inch than CAT 5
▪ UTP is cheaper than STP
▪ Media of choice in most LANs
Shielded twisted pair (STP)
▪ Wires are twisted in pairs and surrounded in a metallic shielding to
minimize EMI
▪ Outer shielding minimizes EMI, but makes STP cost more than UTP
Twisted pair connectors
RJ-45
● 8-pin connector in Ethernet networks
● Most Ethernet use only 4-pins
▪ RJ-11
● 6-pin connector
● Commonly only 2 or 4 pins are used
● Commonly found in telephone systems
Registered Jack (RJ)
▪ Used to carry voice or data which specifies the standards a device needs
to meet to connect to the phone or data network
Bandwidth
▪ Theoretical measure of how much data could be transferred from a
source to its destination
Throughput
▪ Actual measure of how much data transferred from a source to its
destination
Cable Legths
▪ Keep cable runs under 70 meters from the IDF to the office
Straight-through Patch cables
Contains the exact same pinout on both ends of the cable
▪ T-568B is the preferred standard for wiring a building if no pre-existing
pattern is used
● Data Terminating Equipment (DTE)
o “Endpoint” devices that connect to a piece of data
communications equipment or DCE (e.g. laptops,
desktops, servers, and routers)
● Data Communications Equipment (DCE)
o Includes things like switches, modems, hubs, and bridges
● Connecting DTE and DCE devices
o Straight-through
▪ DTE to DCE
▪ DCE to DTE
o Crossover
▪ DTE to DTE
▪ DCE to DCE
Crossover Cables
▪ Swaps the send and receive pins on the other end of the cable when the
connector and its pinout are created
Pinouts (568A/568B)
▪ TIA/EIA-568A and TIA/EIA-568B are standard
▪ Orange and Green pairs swap
Medium Dependent Interface Crossover (MDIX)
An automated way to electronically simulate a crossover cable connector
even if using a straight-through patch cable
▪ If a switch doesn’t support MDIX, use a crossover cable to make them talk
Plenum and Non-Plenum Cable
▪ Plenum Cable
o A special coating put on a UTP or an STP cable that
provides a fire-retardant chemical layer to the outer
insulating jacket
o Minimizes dangerous fumes if cable on fire
o Safe for use in ceilings, walls, and raised floors
▪ Non-plenum Cable
● Also known as PVC
● Normal UTP/STP rated cable
● Cannot be used in raised floors, ceilings, or walls
Fiber Media: FIber Optic
▪ Uses light from an LED or laser to transmit information through a glass
fiber
● Immune to EMI
● Uses light instead of electricity
▪ Benefits:
● Greater range (many miles)
● Greater data-carrying capacity (measured in Tbps)
▪ Types:
● Multimode Fiber (MMF)
● Single-mode Fiber (SMF)
Single-Mode Fiber (SMF)
▪ Used for longer distances and has smaller core size which allows for only
a single mode of travel for the light signal
▪ SMF’s core size is 8.3-10µ in diameter
Multimode Fiber (MMF)
Used for shorter distances and has larger core size which allows for
multiple modes of travel for the light signal
▪ MMF’s core size is 50-100µ in diameter
▪ Up to 2 kms or less
Wavelength Division Multiplexing (WDM)
Combines multiple signals into one signal and sends over a single fiber
optic strand using different wavelengths of the laser light source
Transceivers: Copper vs. fFiber optic cables
▪ Fiber-Optic Advantages
● Higher bandwidth
● Longer distances
● Immune to EMI
● Better security
▪ Copper Advantages
● Less expensive
● Easy to install
● Inexpensive tools
Media Converters
▪ Convert media from one format to another
▪ Layer 1 device
● Physical conversion of signal only
▪ Examples:
● Ethernet to Fiber Optic
● Fiber Optic to Ethernet
● Coaxial to Fiber
● Fiber to Coaxial
Transceivers
Device that sends (transmits) and receives data
Bidirectional
o Devices take turns communicating
o Known as half-duplex
Duplex
Full duplex occurs when devices can both communicate at
the same time
o Half duplex occurs when devices can either transmit or
receive, but cannot do both at the same time
Transceivers used in switches/routers: GBIC
Standard, hot-pluggable gigabit Ethernet
transceiver (copper or fiber)
Small Form-factor Pluggable (SFP)
Compact, hot-pluggable optical module transceiver
▪ Support up to 4.25 Gbps
▪ Known as Mini-GBIC
SFP+
Enhanced SFP
▪ Support up to 16 Gbps
Quad Small Form-factor Pluggable (QSFP)
Compact, hot-pluggable optical module transceiver
▪ Supports up to 100 Gbps
Cable Distribution
An organized system to connect the network’s backbone
in the main distribution frame to the intermediate distribution frames and finally
to the end user’s wall jacks
Cable Distribution System
▪ Use an organized system that is hierarchical
● Demarcation point
o The entrance facilities where you WAN connection will
enter your building
▪ Components
● Entrance
● Cross-connect facilities
● IDF
● Backbone wiring
● Telecommunications closet
● Horizontal wiring
● Patch Panels
● Work area
Patch Panels (Copper)
▪ Device with jacks to connect wiring from the jack to a network switch in a
flexible manner
▪ Has punch downs (like a 110 block) on the back side that is used to
connect wiring to wall jacks in building
▪ Front has RJ-45 jacks
Patch Panels (Fiber)
▪ Connect fiber jacks throughout building to a single patch panel in
network closet
▪ Front uses patch cables to connect different wall jacks and switch ports
