Week 8 - Intro Network Part 2

Question 1

Define ‘Distributed system’

Answer 1

It is one where multiple networked computers work together on tasks,co-ordinating their actions by exchanging messages.

Question 2

Why is concurrency consider as a norm with the internet?

Answer 2

• No global notion of correct time
• Each component in the network may fail independently

Question 3

Define ‘Intranet’

Answer 3

Within the huge distributed system of the internet, an individual or separate internet.

Question 4

Intranet

Question 5

Define Firewalls

Answer 5

A network security system that monitors and controls incoming and outgoing network traffic based on predetermined secuity rules

Question 6

What are two things that a firewalls does?

Answer 6

1. Establishes a barrier between the trusted internal network (the intranet) and the untrusted external network (internet)
2. Filter incoming packets based on their source,destination or protocol.

Question 7

Key Terms

Answer 7

• Speed: How fast data is transmitted on the network.
• Bandwidth: Maximum amount of data the network is capable of transmitting between two given nodes in a certain amount of time.
• Throughput: The actual amount of data transmitted between two give nodes in a certain amount of time.

-Link Bandwidth: A given link in the network.

Question 8

Define Delay (latency)

Answer 8

How long will the packet take to be sent from node to the next?

• The time between the sending and receiving of data between two adjacent points in the network

Question 9

Define Queuing

Answer 9

When packets wait in the router buffer to be transmitted on the link.

Question 10

Where are the packets stored?

Answer 10

It is in the router buffer until it is their turn to be forwarded on:
- Arrival Rate (R1 and R2) exceeds the transmission rate (R3)

Therefore, it means that the packets will queue in the router buffer.

Question 11

What happens once the router buffer fills up and another packet arrives?

Answer 11

• The packet is lost forever

Question 12

What is the end-to-end delay of the packet transferred below?

Answer 12

The delay between the sender sending a packet and the receiver receiving it .

Question 13

What is a ‘Network protocol’?

Answer 13

A set of guidelines that determine how network devices should communicate in a given context.

Question 14

Types of protocols

Answer 14

• HTTP and HTTPS are web application protocols
• SMTP and POP3 are email application protocols
• TCP and UDP are packet transportation protocols
• IP is a network communication protocol