3. Communication

Question 1

First layer in the TCP/IP 5-layer stack model name and role (3)

Answer 1

Physical layer
- Transmits raw data
- Consists of hardware such as switches and routers
- Deals with all aspects of setting up and maintaining a link between communicating computers

Question 2

Second layer in the TCP/IP 5-layer stack model name and role

Answer 2

Data link layer
- Sends data from the network layer (contains routers) to the physical layer (to transmit raw data)
- Divides the data to be sent into data frames
- Handles the acknowledgements sent from receiver - handshaking
- Ensures incoming data has been received correctly

Question 3

Third layer in the TCP/IP 5-layer stack model name and role

Answer 3

Network layer
- Responsible for the addressing and routing of data
- Includes routers to direct data from sender to reciever

Question 4

Fourth layer in the TCP/IP 5-layer stack model name and role

Answer 4

Transport layer
- Ensures data is transferred from one point to another reliably and without errors
- Responsible for making sure data’s sent and received in correct order
- Acts as an interface between communicating computers and the network

Question 5

Fifth layer in the TCP/IP 5-layer stack model name and role

Answer 5

Application Layer
- Provides interfaces to the software to allow it to use the network

Question 6

IP address definition

Answer 6

An address using the Internet Protocol which can uniquely identify every device on the internet, thus allowing communication between them

Question 7

How does DNS work?

Answer 7

• User types website’s name into browser
• Browser sends it to a DNS server
• Server checks in its database and finds corresponding IP address
• This unique address is then used to route you to the appropriate webpage

Question 8

Circuit switching defintion

Answer 8

Provides a dedicated link between 2 nodes; no other data can be transmitted along same route while the connection’s open; e.g. landline phone system

Question 9

Circuit switching ✅ and ❌

Answer 9

✅Reliable, fast once connection established, error free
❌Takes time to establish connection

Question 10

Packet switching definition

Answer 10

Data is split into packets which are routed (along the best route) along the network by routers and then reassembled e.g. The Internet

Question 11

Packet switching ✅ and ❌

Answer 11

✅Don’t need dedicated line, can take alternative routes, efficient - only one packet needs to be re-sent
❌Could arrive in wrong order, delay til all arrived, large memory to hold packets until all arrived

Question 12

Contents of a TCP/IP packet (6)

Answer 12

• Source address
• Destination address
• info allowing reassemblage (no. split into, the packet’s no.)
• the data
• a checksum that checks the data hasn’t been corrupted

Question 13

Ring network - describe

Answer 13

Nodes are connected in a ring - each node connects to 2 others

Question 14

Ring network ✅and ❌

Answer 14

✅High transfer speeds - no collisions/bottleneck - single path in one direction - simple definition
❌ if one node fails, network fails

Question 15

Bus network definition

Answer 15

Nodes are directly connected to a common linear cable/bus

Question 16

Bus network ✅and ❌

Answer 16

✅Cheap and easy to set up and add new nodes
❌Not that secure
Can be slow if heavy traffic
Break in main bus - break network

Question 17

How data is transferred in ring and bus network

Answer 17

Message is sent along - location check if it’s for it - not for it them passes on to next node - if for it - download

Question 18

Mesh network definition

Answer 18

Uses direct communication between each node

Question 19

Mesh network ✅ and ❌

Answer 19

✅reliable
✅very robust- no single point which will bring down network
✅data can be routed both via other nodes and directly transported
❌expensive and complex to set up

Question 20

Wired network ✅ and ❌

Answer 20

✅ transmission speeds are faster and more secure
❌ difficult and expensive to install

Question 21

Wireless network ✅and ❌

Answer 21

✅ mobile equipment can log in
✅ easy and cheap to install
❌ can be hacked more easily
❌ transmissions speeds slow as more users join

Question 22

Network definition

Answer 22

A collection of computing devices connected together

Question 23

Network ✅ and❌

Answer 23

✅ share hardware, software and data
✅ computers can communicate
✅ administration can be centralised
✅ can log onto any device
❌ viruses can spread to all computers ❌hackers can access whole network
❌can be pricey
❌slower

Question 24

LAN definition

Answer 24

Local area network
Computer systems are all located relatively close to each other

Question 25

WAN definition

Answer 25

Wide access network
Computer systems are all located far from each other e.g internet
LANS can be linked using WANS

Question 26

Star ⭐️ network definition

Answer 26

Each node connected to a central node (file server/hub)

Question 27

Star ⭐️ network ✅ and ❌

Answer 27

✅ fast connection
✅ simple fault finding
✅ reliable
✅ high transfer speeds (fewer collisions)
❌$$🫰💵💰
❌main switch fails - network fails
❌central switch can get congested

Question 28

Domain name defintion

Answer 28

Domain names are user-friendly names that save us from having to remember IP addresses.

Question 29

DNS definition

Answer 29

Domain Name Servers convert domain names to the IP addresses needed to locate resources on the internet

Question 30

URL defintion

Answer 30

The unique address of a webpage or other internet resource

Question 31

What should protocols consists of

Answer 31

A set of instructions
- a handshake
- type of error checking to be used
- data compression method
- how both devices will indicate that they have finished sending/receiving

Question 32

Ethernet

Answer 32

Wired protocol

Question 33

WiFi

Answer 33

Protocol for wireless communication
2 standards- Bluetooth and 801.1

Question 34

TCP/IP

Answer 34

Transmission Control Protocol and internet protocol- basic protocol of the internet

Question 35

HTTP-

Answer 35

transfer of web pages over the internet

Question 36

HTTPS

Answer 36

Secure form of HTTP

Question 37

FTP

Answer 37

File transfer protocol- transferring data over the internet

Question 38

SMTP

Answer 38

For email to a mail server - sends the email to a mail server

Question 39

POP3 and IMAP

Answer 39

For email between computer systems