Cabling and Topology Flashcards
Network Topology?
The way that cables and hardware connect to each another
Bus Topology?
single cable connects all computers in a line
Ring Topology?
connects all computers with a ring
How was data sent in a bus topology?
- out on the entire bus
- terminations needed to stop signal from reflecting
How was data sent in a ring topology?
- moved in a circle from one computer to the next
- no terminations were needed
- break in the cable stops data flow
How is data sent on a star topology?
- used a central box
- offered fault tolerance, if cable broke, the rest of the computers could still communicate
Physical topology?
How the cables look
Signaling Topology
how the signals travel electronically
also called logical topology
Hybrid topology
any topology that combies physical and logical
What topology is used today?
Star bus
Mesh topology?
Every computer connects to every other computer via two or more routes
partially meshed topology?
at least 2 machines have redundant connections
Coaxial cable
- central conductor wire (usually copper) surounded by an insulating material, which is sorrounded by a braided metal shield
- the center wire and metal shield share a common axis
- shields data transmissions from interference
EMI
Electromagnetic interference
- other devices generate magenetic fields (lights, fans, copy machiens, refridgerators), and these fields cause current when they cross an electrical wire
Early coaxial connections
BNC
Coax used for cable television
RG-59
75 Ohms
F-Type
Coax used for internet
RG-6
75 Ohms
F-Type
always thicker than RG-59
Coax rating
RG (radio guide) rating
Coax used for networking
RG-58
50 ohms
BNC
reduce crosstalk
use twisted pairs of wires
the more twists per foot, the less crosstalk
STP
Shielded Twisted Pair
- twisted wire pairs surrounded by shielding to protect from EMI
UTP
Unshielded Twisted Pair
- twisted wire pairs surrounded by a plastic jacket
- no protection from EMI
Cat ratings are in
MHz, the highest frequency a cable can handle
Cat 3
16 MHz
16 Mbps
Cat 5
100 MHz
100 Mbps
Cat 5e
100 MHz
1 Gbps
Cat 6
250 MHz
10 Gbps
Cat 6a
500 MHz
10 Gbps
Cat 7
600 MHz
10+ Gbps
Telephone wires
RJ-11, supports up to two pairs of UTP
Fiber optic cable
- Core (glass fiber)
- Cladding (relective part)
- Buffer (give strength)
- Insulating Jacket
How are fiber optic cables sized?
Core and cladding measurements
MMF
Multimode Fiber
- uses LEDs for light
- 850nm wavelength
SMF
Single-mode Fiber
- uses lasers for light
- prevents modal distortion
- 1310 or 1550 nm wavelength
Fiber connections
ST (stick/twist)
SC (stick/click)
LC (little connector) , duplex
MT-RJ, duplex
DB-9
9-pin serial port
56,000 bps
DB-25
25 pin parralel port
2 Mbps
Which topolgy is most commonly used today in wireless devices?
Mesh