Understanding Local Area Networking Flashcards
What is a LAN?
A local area network (LAN) is a group of two or more computers that exchange data. Usually confined to a small area, like an office building.
Why do organisations need LAN’s?
Sharing: of files, databases and media
Communication: email, instant message and VoIP
Money: increase of efficiency
What is Network Documentation?
Any information that helps describe, define and explain how computers are connected in a physical and logical way.
What does Serial data transfer mean?
The transfer of data one bit at a time. A single transfer via a single-bit stream
What things happen when data is sent over the network?
The data is packaged by the OS into a packet.
The packet is then placed inside a frame by the network adaptor.
The network adaptor then breaks down the frame into a serial data stream that is sent over the cables via a single-bit stream.
The receiving PC recreates the frame of data from the single-bit stream and then subsequently strips the frame so only the packet remains.
The packet is then opened by the receiving OS and can now be accessed by a user.
What is Ethernet?
A set of rules that govern the transmission of data between network adaptors and various central connecting devices.
What common types of Ethernet are there?
- 3u (Fast Ethernet) 100Mbps
802. 3ab (Gigabit Ethernet)
What advantages does switching have?
Only sends unicast traffic (data sent to one host only)
Reduce network traffic
Reduced packet loss and duplication.
What is another name for data transfer rate?
Bit rate
What are the differences between Mbps and MB?
Mpbs - bits per second (speed)
MB - bytes of storage (size)
Why is an IP address important?
It defines each host/computer
What is a subnet mask?
A group of four numbers that define what IP network the host/computer is a member of.
Could a computer with the subnet mask of 255.255.0.0 communicate with a computer with a subnet mask of 255.255.255.0?
No, because the computers that are trying to communicate need to have the same subnet mask so they can recognise each other through the network.
How does a computer see an IP Address?
As a 32-bit dotted-decimal number (Binary)
How many bytes/octects does an IP have?
Four.
e.x. 192.168.50.251
Bytes/Octets - 1 . 2 . 3 . 4
How many bits does a full IP have?
32
This is because each octect is 8 bits, therefore, 8*4=32
What is a WLAN?
A Wireless Local Area Network
What is a VLAN?
A virtual local area network (VLAN) is a group of hosts with a common set of requirements that communicate as if they were connected in a normal fashion on one switch, regardless of their physical location.
Why is a VLAN implemented?
To segment a network, reduce collisions, organise the network, boost performance and increase security
What does a VLAN do?
It compartmentalises a network and isolates traffic upon that network
What is the difference between a subnet and a VLAN?
A VLAN can be set up in a physical manner whereas a subnet cannot be
What is the most common type of VLAN?
The most common type is a port-based VLAN
What is the usual standard associated with VLAN’s?
IEEE 802.1Q - this modifies Ethernet frames and tagging them with the appropriate VLAN information. This information then determines the VLAN to which to direct the Ethernet frame.
What can a perimeter network also be called?
A DMZ (Demilitarised Zone)
What functionality does a DMZ provide?
To allow users outside of a company LAN to access specific services located on the DMZ
What are two common DMZ configurations?
Back-to-Back; DMZ is situated between two firewalls
3-Leg - DMZ is attached to a separate connection of the company firewall
What is network topology?
Network Topology defines the physical connections of hosts in a computer network
List three types of physical network topologies
Star
Mesh
Ring
Define how a Star Topology is configured
The hub/switch is connected to each PC via a single cable
Define how a Mesh Topology is configured
Every computer connects to every other computer, no central connecting device is needed. Number of network connections that each computer needs is the total number of computers minus one.
Define how a Ring Topology is configured
Each computer is connected to the network using a closed loop
How does a token ring pass information?
A token system is used and this means that there are no collisions.
