A+ 1001: Networking Flashcards
LAN
Local Area network
local devices connected together on a hub or wap (wireless access point)
Ethernet
Network protocol that defines network card type, cabling, connectors, data protocols etc.
Data can only be sent in chunks of 1500 bytes (Frame) a time. This prevents networks from being clogged up by large documents
Devices on Ethernet are identified by their MAC address
MAC address
Media Access Control Address
identifies a host on a LAN
48 bit address / 12 hexadecimal characters
first six characters is the OEM ID (provided by IEEE)
How to find mac address on computer
Can be found by typing ipconfig /all on a windows machine, and looking for the “physical address”
on MAC and Linux systems the command is ifconfig
FRAME
protocol used to communicate on ethernet
Made up of:
- Destination Mac
- Source Mac
- Data
- FCS (frame check sequence)
Max 1500 of data with each frame
FCS is an algorithm that checks whether the data is in good order
Difference between HUB and SWITCH
REPEATER
Hubs are repeaters. They make copies of the incoming message and send a copy to each device on the network.
Switches are smart repeaters, that have internal MAC Address tables. Switches read the Frame headers to determine the destination mac address, compare it to the MAC Table to find the device port, and the forwards the message to that port. Only the destination device gets the message
BANDWITH
Hubs share bandwidth between nodes
Switches proved full bandwidth for all nodes
Hexadecimal
Base 16 number system
replaces 4-bit binary number with a single number
four bits of ones and zeros
2^4 = 16
0 - 9 A - F
11011101 = DD
According to Ethernet standards how many computers can be connected on a single network
Theoretically 1024
In reality, 39 - 40 computers is the standard size for a LAN
WAN
Wide Area Network
Connects several LANs together through a Router
Uses Logical Addressing (IP) to distinguish between local and remote traffic
Provides each LAN with a network address
All devices on the same network address, can communicate using their MAC addresses, however when a device tries to communicate to a device not on the same network it has to use IP and needs to first send it’s message to the default gateway.
DOCSIS
An alternative protocol to Ethernet
Has unique connector types
Fibre Optic Cable
Fiber Optic Cable
- uses light and not electricity
Different modes of propegating signal
- multimode: Orange cable, uses LEDs
- single mode: Uses lasers (long distance)
Has two wires and connectors, one for send and one for recieve
Plenum and Riser Ratings
Plenum is the space between the ceiling and the roof or the space below the floor
cable covering’s ability to resist fire
PVC (non-plenum), not the kind of wire you want to run in a plenum space
Riser Ratings
A fire-resistance rating for cabling that runs between floors
Need to consult the building codes to see what kind of wire is required.
Coaxial Cable
Coaxial Cable
- Uses RG Ratings
- RG 58 (thin cable, uses BNC connector types)
- RG 59
- RG 6 (Uses F-type connectors)
Twisted Pair cable
UTP (unshielded Twisted Pair)
- The twists help to propagate the signal better
- Can be run for about 100 m from switch to devices
- Uses RJ-45 connector type: It has 8 connectors one for each of the 4 pairs
- CAT (category) ratings:
- – Cat 5: 100 mbps
- – Cat 5e: 1Gbps
- – Cat 6: 1 Gbps (100m) and 50Gbps up to 55m
- — Cat 6a 10 Gbps at 100m
10BaseT (10 Mbps baseband twisted pair)
example
- 1000 BaseT
- 10Gb baseT
2 types:
- Solid Core: Put into the walls. Each wire has a solid core of copper, which carries signals really well
- Stranded: each one of the wires are standed, which makes them very flexible. Used for patch panel cables
The shielded twisted pair has metal shielding around the connector and the entire length of the cable, which protects it from interference from things like electrical motor and florescent light.
Crimps
The connector that attaches to the cable
If the cable is rated, ensure that the connector has the same rating as the cable
Crimping Cables
Cut an inch of jacket
Turn connector upside down, starting on the right count from 1 to 8
Each twisted pair has a solid and striped colored wire
Untwist each wire
Cut them straight
Insert into the crimp
Two standards: TIA 568A and TIA 568B
A: (alphabetical)
1: Green Stripe
2. Green Solid
3. Yellow Stripe
4. Blue Solid
5. Blue Stripe
6. Yellow Solid
7. Brown Stripe
8. Brown Solid
B:
1: Yellow Stripe
2. Yellow Solid
3. Green Stripe
4. Blue Solid
5. Blue Stripe
6. Green Solid
7. Brown Stripe
8. Brown Solid
Crimp
Finally, do a straight through cable Check using a cable tester (fluke networks micro scanner pro)
- Continuity Check
- Wire Map
-
Crossover cable
When you wire a twisted pair with one end using the TIA 568A standard, and the other end TIA 568B.
This is the opposite of a straight-through wich is wired the same on each side
Cross over cables are used to connect one computer directly with another.
structured cabling
Neatly organizing cables in the walls
MDF
Main distribution frame
it is the closet where the equipment is and the cables start from
“U”
a measure of the standard height on an equipment height
Horizontal Run
The wire that runs from the patch panel in the equipment rack to the shield on the wall from which cables connect to
Even though Ethernet allows for 100 meters, according to TIA, the longes horizontal run we can have is 90 meters, which compensates for the patch cables themselves
Patch Panel
The connector panel on the equipment ract
switches connect to the patch panel via a patch cable
How to connect horizontal run to the patch panel on equipment rack
Require
- a 1.10 punch-down tool
- cable tester
- Fox (tone generator) and Hound (tone probe)
TDR
Time Domain Reflectometer
A test that uses the speed of light to detect how long a cable is.
Useful for discovering breaks in cables
What goes at the end of an Ethernet frame?
FCS
The frame check sequence (FCS) goes at the end of an Ethernet frame
MAC addresses are made up of how many bits?
48
How does a switch know the MAC addresses of connected devices?
Switches watch all inbound frames and learn MAC addresses from them, and then update its Internal MAC Address table, where Addresses are associated with ports
MAC addresses can be represented by how many hexadecimal characters?
12
How are WANs identified?
Logical Addresses
Which is not a network cable type?
a. ) Coaxial
b. ) Plenum
c. ) UTP
d. ) STP
b.) Plenum
Plenum describes any type of cable with a fire-resistant jacket. Coax, unshielded twisted pair (UTP) and shielded twisted pair (STP) are all types of network cable.
Multimode fiber optic cables use what for their light source?
Multimode fiber cables use LEDs to generate light pulses.
Which is the best tool to identify a specific cable within a bundle of cables?
a. ) Fox and Hound
b. ) TDR
c. ) Continuity tester
d. ) Punch down tool
A tone probe and tone generator, also called a Fox and Hound, can easily identify a specific cable within a bundle. Neither a TDR nor a continuity tester can identify a specific cable in a bundle. A punch down tool is not a diagnostic tool.
Solid-core cabling is best used where?
Solid-core cable is used in walls and horizontal runs because it is good for long runs and is not exposed to frequent bending. It is not used in environments where frequent bending occurs such as in patch panels, workspaces, or anywhere that it will be flexed regularly by people handling, stepping on, or tripping over it.
