NETWORKS PART 3 Flashcards
What does every device on a network have
Every device on a network has a Network Interface Card (NIC) - although this may be built into the motherboard
What does every NIC have
Every NIC has a Media Access Control (MAC) address
What is MAC addressing used for
MAC addressing is used to route frames on a local area network (LAN)
A MAC address is assigned to devices; its use within a network
MAC address are mainly used by the Ethernet protocol on LANs
LAN switches read the MAC addresses and use them to direct data to the right device
They are uniue to the device and cannot be changed
Features of a MAC address
Example of MAC address: 00:0a:95:9d:68:16
Each MAC address is unique to every network interface card
Why is IP addressing used
If the LAN is connected to a WAN such as The Internet then we need a different addressing method
What is IP addressing used for
IP addressing is used to route packets on a wide area network (WAN):
IP addressing is used to route frames on a wide area network (WAN)
On a WAN we refer to frames as packets
Used when sending data between TCP/IP networks e.g. over the interent
Assigned either manually or automatically before the device can access the network
How many versions of IP addressing are there
There are two versions of IP addresses IPv4 and IPv6 (IP version 4 and IP version 6)
Features of IPv4 address
32-bits in size
Written as four numbers separated by periods (.), each number in the range 0-255
Example 69.89.31.212
Why is IPv4 being replaced by IPv6
IPv4 is being replaced by IPv6 because unique static addresses are running out
Features of IPv6 address
128-bits in size
Written as eight groups separated by colons ( : ), each group made up of four hex values representing 16-bits
Example: 2001:0dn8:85a3:0000:0000:8a2e:0370:7334
What are standards
Standards are a set of specifications for:
Hardware
Software
Purpose of standards
Standards make it possible for:
Manufactures
Producers….
…. to create products and services which are compatible with each other
What would happen if there were no standards
Without standards most devices wouldn’t be able to successfully interact or communicate.
Examples of different protocols
Protocol acronym - Protocol Full Name - Area/Purpose
TCP/IP (Transmission Control Protocol / Internet Protocol)
- Communicate over LANs and WANs
HTTP (Hypertext Transfer Protocol) - Web page requests
HTTPS (Hypertext Transfer Protocol Secure ) - Web page requests
FTP (File Transfer Protocol) - File transfers
POP (Post Office Protocol) - Email
IMAP (Internet Message Access Protocol) - Email
SMTP (Simple Mail Transfer Protocol) - Email
What is a protocol
A protocol is a set of rules (like a language/ guidelines devices follow) that allows two devices to communicate (in some way)
Purpose of TCP/IP protcol
This group of protocols are used over the internet
The Transmission Control Protocol (TCP) provides an error free transmission between two routers. (provides an error free way of transmitting data between two routers)
The Internet Protocol (IP) routes packets across a wide area network
Together they make up the TCP/IP protocol stack which is the (basic) foundation of all communication over The Internet.
(routing packets is like determining which route the packets take to get to a set destination)
Purpose of HTTP protocol
Used by web browsers to access websites and communicate with web servers
It is the fundamental protocol of the World Wide Web (WWW).
When you type in a web address in a web browser and you look at the address at the top, you will often see HTTP
You can see that this is the protocol being used so that you can receive the web page in your browser
Purpose of HTTPS protocol
A more secure version of HTTP (http purpose: used by web browsers to access websites and communicate with web servers) - Encrypts all information sent and recieved
Purpose of FTP
Used to access, edit and more files between devices on a network e.g. to access files on a server from a client computer
Purpose of POP
Used to retrieve emails from a server. The server holds the email until you download it, at which point it is deleted from the server
Purpose of IMAP
Used to retrieve emails from a server. The server holds the email until you delete it - you only download a copy. Used by most web-based email clients
Purpose of SMTP
Used to send emails. Also used to transfer emails between servers
What is a layer
A layer is a group of protocols which have similar functions
What is the concept of layering
PURPOSE OF LAYERING
The concept of layering is to divide the complex task of networking into smaller, simpler tasks that work with each other.
Features of layering
The hardware and/or software for each layer has a defined responsibility
Each layer provides a service to the layer above it.
The advantages of layering include
Reduces the complexity of the problem into manageable sub-problems .
It breaks network communication into manageable pieces. This helps developers concentrate on only one area of the network without having to worry about the network.
As layers are self-contained, they can be changed or developed without the other layers being affected
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It makes it easier to identify and correct any networking errors and problems
Devices can be manufactured to operates at a particular layer
Each layer is specialised to perform a particular function
Having standards for each layers forces companies to make compatible, universal hardware and software. So Products from different vendors will work together ( so that products from different manufactures will be able to communicate with each other)
The different layers can be combined in different ways as required
