Chapter 2 - Cabling and Topology Flashcards
Bus Topology
Connected all computers in a line using a single cable
Entire network stops working if cable breaks at any point
Ring Topology
Connected all computers with a ring of cable
Entire network stops working if cable breaks at any point
Star/Hub and Spoke Topology
Used a central connection box for all computers on the network
Offers fault tolerance, if one cable broke all the other computers could still communicate with the central point
Not very successful because Bus/Ring popular and inexpensive
What are the drawbacks of Bus and Ring Topologies?
Entire network stops working if cable breaks at any point
Physical Topology
How the cables physically look
Logical Topology
How the signals travel electronically
Mesh Topology
Every computer connects to every other computer via two or more routes
Partially Meshed
At least two machines have redundant connections, but not all machines are directly connected
Fully Meshed
Every computer connects to every other computer
Coaxial Cable
Contains central copper conductor wire surrounded by insulating material which is then surrounded by a braided metal shield
Shields data transmissions from EMI
F-type Connector
Connector that screws in
All coaxial cables have a ___ rating
Radio Guide (RG)
Ohm Rating
Relative measure of resistance on the cable
Only important measure of coax
Twinaxial Cable
Type of coax that contains two central copper conductors wrapped around a single shield
Generally used between equipment in a rack, like switches
When twinaxial cable is used between equipment in a rack, it is called ___
Directly attached cable (DAC)
Twisted Pair
Each pair in cable works as a team either transmitting or receiving data.
What is the benefit of cable using a pair rather than a single wire?
Reduces crosstalk
STP
Shielded Twisted Pair
Twisted pairs surrounded by shielding to protect against EMI
UTP
Unshielded Twisted Pair
Twisted pairs surrounded by a plastic jacket. No protection against EMI, so when installing must be careful.
Much less expensive
Cat Ratings
Designed to help network designers get the right cable for the right technology
Rated in megahertz (MHz)
MHz
Megahertz
Indicates highest frequency cable can handle
Bandwidth
Maximum amount of data that goes through the cable per second
RJ-45
Common name for UTP cable connectors.
This name is incorrect but has become so common its now the standard name.
True name is 8 Position 8 Contact (8P8C)
Fiber Optic Cable
Transmits light instead of electricity. Can be regular or laser light.
Requires two cables, one for sending, one for receiving.
Where is fiber optic especially beneficial?
Areas with high EMI
Long distance transmissions
What does fiber optic cable consist of?
Core - glass fiber itself
Cladding - part that makes light reflect down the fiber
Buffer
Insulating Jacket
Multimode Fiber
Uses LEDs to send light signals
Single Mode Fiber
Uses laser signals
Modal Distortion
Signals sent at the same time don’t arrive at the same time because the paths differ slightly in length
Single Mode Fiber prevents this
Nanometers (nm)
Measurement of light wavelength
Fiber optic cabling rated in nanometers
PVC
No significant fire protection, if burned it creates a lot of smoke and fumes
Plenum
Creates way less smoke and fumes than PVC but is 3-5x more expensive.
Required for most city ordinances
IEEE
Institute of Electrical and Electronics Engineers
Defines industry wide standards that promote the use and implementation of technology
IEEE 802 Committee
Defines frames, speeds, distances, and types of cabling to use in a network environment
802.1
Higher Layer LAN protocols
802.3
Ethernet
802.11
Wireless LAN
802.15
Wireless Personal Area Network
