Networks And E-communication Flashcards
Nodes
Networking consists of computing devices
LAN
Local area network
Describes the networking capabilities of a group of computers close to each other
Share files, printers, applications
What does a network need
Hardware that acts as a source or sender to a destination or reciever
LANS use cables like?
Inexpensive cables
Ethernet cables
Network adaptors
Switches
What’s does network hardware include
Nodes(computing devices)
NICS(network interface cards to which media connects(cables)
Connecting devices (switch, bridges, routers, repeaters
What are nodes connected with
Transmission media(network media)
3 types of cables
Coaxial cable
Twisted pair cable
UnshieldedTwisted pair cable( Ethernet cable)
Are coaxial cables still used today and why are they good??
No
Expensive
Most resistant to interference/cross talk
Less noise > less repeaters
Describe coaxial twisted pair cables
Core of copper ,surrounded with insulation , braided metal shielding with outer cover
Describe twisted pair cable
Consists of two insulated strands of copper twisted around each other
Why is the twisting so effective
To prevent electrical interference from other cables and outside sources
Effect against crosstalk
Another term for Unshielded Twisted pair(UTP)
Ethernet cables
What is a problem with all types of cabling
Crosstalk
What is crosstalk
Signals from one line interfering with signals from another line
Is UTP susceptible for crosstalk??
Yes
What are the problems for copper cables
Attenuation(signal strength is lost over distances)
Electro-Magnetic interference (signals from other sources can interrupt the traveling signals in copper cables)
Eavesdropping( signals can be intercepted by outsiders)
Crosstalk( signals can interfere with each other )
What is fibre optic?
Communication cable that carries digital data in fonts of pulses of light
No electrician impulses
Cannot be stolen
Why is fibre optic effective
High speed, high capacity data transmissions because of lack of attenuation
How does fibre optic work
For how long can they carry a signal
Two strands
One to transmit data
Other to receive data
For many kilometers
What is signal mode
One mode of transmission
Eliminates overlapping of light waves causing distortion
What is multi mode
Light is dispersed into many paths
light/data clashes and makes data incomplete and unclear
What are NICS
Network interface cards
Connection between a network cable and a computer
Unique address(MAC) to each computer so that it can be distinguished from all the other network cards on the internet
MAC -media access control if linked to the IP (internet protocol) address
MAC and IP addresses are stored in the ARP(address resolution protocol) ram of the NIC
ARP also stores Mac addresses of other devices so that it knows where the data is coming from
What does the term topology mean
The physical set up of a network , how the network devices are connected
3 kinds of topologies
Star ring bus
Combination of topology
Hybrid topology such as star-ring topology
What is a star topology
The cable from the NIC to a hub or a switch has a signal that’s boosted to every computer connected to it through UTP cables or Fibre Optic
Advantages of Star topology
Easy to set up and maintain
Prob with one, only stays with one
Add/ remove no prob
Common
Disadvantages of Star topology
Large amounts of cabling from nic to hub/switch
Hud/switch fails all fails
HUD/siwtch is costly
What is a bus topology
All nodes connect to a single cable which has a terminator at the end to stop the signals from bouncing out. Coaxial cables
Advantages of a bus topology
Less cabling
No hub/switch to boost signals
Easy to extend by adding nodes but this disrupts the network
Disadvantages of bus topology
Faults are difficult to trace because of 1 main cable
Main cable at fault the whole network shuts down
Can get congested because of 1 main cable
What is a ring topology
All nodes are connected to each other in a closed loop
The signals travel in one direction passing through each computer and the computer boosts the signal before sending them to the next computer
2 rings
Signals pass through both
One ring fails
Signals pass through the other
Advantages of ring topology
Very orderly network
Duplicates data signals
Can easily create a larger ring network
Disadvantages of ring topology
One malfunction all malfunctions
Moves/ additions and changes can disrupt with network
Slower than Star topology
Name 4 network hardware connection devices
Switches
Repeater
Bridge
Router
What are switches
Boosts signals coming into them and then send them on
What is more commonly used today than switches
Ethernet technology
What can Ethernet technology be divided into
Frames or packets
What do frames do
Store details and source of a destination machines(MAC and IP addresses in NICS)
What do the switches look at before sending on a signal
They look at the Destination of the frames of data and send only the signal to that specific node with that specific address
What is a repeater
Used to connect network segments of signals over a long distance because the signal strength weakens (attenuation) and must be boosted
Is a repeater intelligent
No,
Takes signal and simply boosts it without looking at destination addresses(Mac or ip)
What are bridges
Grabs a signal, boosts the signal
Looks at destination addresses and if the segments do not have the same protocols the data will not be sent
What is the function of a bridge
Make intelligent decisions about whether to pass on the signals on to the next segment and must Hereford have the same Protocols
What is a router
It is a sophisticated device To connect different networks that can use the same protocols
What is the functions of a router
Boosts signal
Uses nodes addresses to determine the best path for data to travel to their destinations
Can determine best, quickest, most cost-effective route to send data
Can analyze the frame being sent over a network, change how the frame is packaged and then sent to another network or over different types of networks
Name two types of LAN technologies
Ethernet LAN
FDDI( fibre distributed data interface)
What is the most commonly used technology
Ethernet LAN
How do the nodes communicate in an Ethernet LAN
They communicate using short messages called frames
What does the Ethernet protocol provide
It provides the rules for constructing frames such as size, both sender and receiver addresses
What type of access does fast Ethernet use?
CSMA/CD media access method
How are the nodes normally connected in an Ethernet LAN
In Star-hybrid topology
What type of cabling does Ethernet LAN use
Fibre optic or UTP
Where is gigabit Ethernet commonly used
In schools, companies, universities and ISP (internet service providers)
What can Ethernet replace
FDDI ( fibre distributed data interface)
What can effect the speed of the Ethernet LAN?
Number of nodes in a LAN (many transmissions, more Collins more delays )
Distance between nodes( weakens signal and interference)
Technology used needs to be consistent(new tech or there will be speed problems)
What are Ethernet networks called when they use switches
Switches Ethernet networks
What does FDDI strand for
Fibre distributed data interface
What is FDDI based on
This is based on the outdated token ring media access method where only one network in the node could transmit
How did the token ring access method work??
A token circulated around the network if a node could transmit it it had the token ensuring no collisions
How does FDDI transmit data?
By the use of light
How does FDDI work using the light to transmit data?
Optic rings are used with each ring passions a token in opposite directions
How does FDDI transmit
At high speeds and over long distances
Why are LANs referred to as local
It has physical limitations to the distance of the cabling and the number of nodes you can connect to it
What are the limitations in a star topology
The number of ports on the switch
What is another characteristic that can limit LANs
The electrical characteristics
What must network designers need to create a balance of LANs
Type of cabling used
Transmission rates
Signal loss over distance
Name another factor that creates limitations for LANs
Delay
Explain the delay in an Ethernet network
The cabling is so long that the workstations don’t detract transmission and therefore causing Collision and corrupted data
What are wireless LANs ??
A LAN without wires
Is wireless network always completely free of cabling
No
What do most wireless networks consist of
The make use of wireless components that communicate with the network through uses of cabling
How can wireless networks be set up
Independently or in conjunction with existing networks
What can wireless networks do
Provide temporary connection
Help provide backup to existing network
Some degree of portability
Extreme networks beyond cable capabilities
Where are wireless networks more oftenly used
In mobile devices
Companies
Places where it is difficult to install cabling
How does a wireless network work
Each device on a wireless network has a wireless network interface card with a transceiver so that people can communicate on the network
What does wifi stand for
Wireless fidelity
What is wifi
A high speed internet and network communication without the use of wires
Is basically wireless LAN
Name 6 wireless connections
Wireless access points
Hotspot
Wireless bridge
Long range worked bridge
Wireless mesh network(WMN)
Bluetooth
What is a wireless access point
Fixed wireless base station or access point
What does each access point connect to
A wired backbone so that users can connect to the internet or other users of other wired network services
What doe wireless access points provide
Connection to a wired Ethernet
What does a access point plug into
It plugs into a switch or a router and the signals are sent out wirelessly
What is a hotspot
Site that offers access to a wireless LAN with the use of a router or wireless access points to to an ISP
What is a wireless bridge
Easy way to link network segments without cables . Connected to something else that’s wireless
Why is wireless bridge beneficial
Connects building where laying cables us difficult or buildings are separated by roads etc
What is long range wireless bridge
When the wireless bridge will not reach far enough to get connection
What does WMN
Wireless Mesh Networks
What are Wireless mesh networks
Mesh nodes that share network connection across a large area
What are mesh nodes compared to
Router
How do these mesh nodes work
Signal bounces from one node to the next and uses dynamic routing
What is dynamic routing
Nodes choose the quickest and safest path for the signals to travel
What is the biggest advantage of mesh networks
They are truly wireless, only 1 node needs to be physically wired to a network connection. That 1 node then shares its connectivity wireless with all the other nodes
The more nodes, further the connection goes and then there’s a cloud of connectivity
What is Bluetooth
Wireless technology that sends data over short distances
How are signals sent
From fixed mobile devices creating a Personal Area Network(PAN) with high levels of security
When is a LAN a WAN
The internet itself
What is the function of a Wan
To connect users from different LANs
