Week 7 - Networks And Distributed Architectures

Question 1

What is the idea behind networks and distributed architectures?

Answer 1

Machines powering our software resides in different places now. There is a separation between physical and software applications

Question 2

What are examples of local area networks?

Answer 2

LAN: ethernet (wired) cabled network or wi-if (wireless)

Question 3

What is an ethernet

Answer 3

Shared wired connection

Question 4

What is a wi-if

Answer 4

Shared radio channel

Question 5

Why are LAN’s useful?

Answer 5

You can isolate them from external networks and you can manage different components of the network.

Question 6

What are the benefits and shortcomings to wi-fi

Answer 6

[+] Flexibility of connecting from anywhere. You don’t need specific, designated end-points
[-] can be interfered with

Question 7

What are the benefits of ethernet?

Answer 7

[+] faster connection

Question 8

What is an IP address and why do you need it?

Answer 8

IP stands for internet protocol. It’s an address so that the sender knows who is requesting and receiving the packet.

Question 9

What is a feature of the IP address?

Answer 9

It needs to be unique and depends very much on the level of network. For example, there is an IP address for nodes at the global network, centralised network and local network.

Question 10

What are the benefits of distribute architectures

Answer 10

You get to manage information at different levels - parcelling them at higher or lower levels.

Question 11

What is my IP (at different levels)

Answer 11

ISP assigned IP - SMU’s IP for connection to ISP
Locally assigned IP - SMU assigns IP for each user

Question 12

How does the packet travel?

Answer 12

Message sent to SMU’s ISP first then the router decides who is the receiver

Question 13

How does information travel?

Answer 13

Data is exchanged on computer networks in packets. The data is split up and the packets are sent out individually, they get routed and switched around.

Question 14

How does the internet work?

Answer 14

The network is connected to other networks, till the point that everyone is connected at some point. This is why the internet is described as distributed.

Question 15

Why is the internet distributed architecture?

Answer 15

There is no central authority controlling the internet. You can connect as a node and have access to the network to send something from one IP to another IP

Question 16

How to ensure standards?

Answer 16

Protocols on open source need to be agreed upon. The standards reflect the standard way of communicating.

Question 17

How is the internet different from the web

Answer 17

The internet is the network, the connection itself;
The web is the part of the internet with which you can access resources (HTML access through URL)

Question 18

How do these resources become accessible?

Answer 18

Search engines

Question 19

What are intranets?

Answer 19

They form part of the deep web and restrict access to search engines. Because these pages are not indexed. They are connected to the internet but not discoverable by google search.

Question 20

What is the dark web?

Answer 20

It forms the part fo the web that is undiscoverable by search engines and intentionally hidden from general access. You will need special tools to access the dark web.

Question 21

What is the goal of the dark web

Answer 21

To anonymise information, the sender and receiver of the messages

Question 22

How does the dark web achieve anonymization?

Answer 22

they use a different protocol

Question 23

What does a VPN do?

Answer 23

A VPN allows you to connect to a main server and route all traffic through that server so it looks like its coming from the VPN.

Question 24

What are the concerns of VPN

Answer 24

Raises privacy issues and questions surrounding reliability. VPN’s may still be subject to production orders

Question 25

What is the tor project

Answer 25

It helps to do its own routing so you can’t tell which place the information originates from (like money laundering)

Question 26

What are some examples of standard protocols?

Answer 26

HTML, TCPIP, SMTP

Question 27

What is IPv4?

Answer 27

IPv4 is an IP address consisting of 4 parts, each part is exactly 1 byte

Question 28

Why did IPv6 come in?

Answer 28

Intended to mitigate the problem of IP address exhaustion under IPv4

Question 29

What’s the purpose of a DNS?

Answer 29

A DNS maps human friendly names to IP addresses

Question 30

What does the Domain Name registrar do?

Answer 30

It registers the domain name. Countries each have their own top-level domain (TLD)

Question 31

What is the client server model

Answer 31

DNS —> IP —> browser has connection from browser (your client) to server. Your browser is the client and the server serves you resource.

Question 32

What is the P2P model?

Answer 32

Peers are considered equal in supplying and consuming resources.

Question 33

What’s the key difference between CSN and P2P?

Answer 33

CSN: designated node is waiting for the request. The role is designated
P2P: there is no designated server. At any given time, if the peer has the desired file to be shared, it can be shared.

Question 34

What is the key limitation of a P2P network?

Answer 34

It only works at scale. If no one is online, the network ceases to exist. You have to incentivise people to use P2P networks

Question 35

What is the concept behind virtualisation

Answer 35

How we enabled cloud computing: the repackaged of service and products.

Question 36

How is virtualisation different from the traditional model?

Answer 36

Under a traditional model, the PC assumes that the hardware and software is bundled in that manner only.
Under virtualisation, apps such as DBS require a lot more hardware to run on. Rather than buying 10000 pieces of hardware, you parcel the RAM to share with other machines.

Question 37

What are the benefits to virtualisation?

Answer 37

Greater efficiency.

Question 38

How does cloud providers features in virtualisation?

Answer 38

You can request how much RAM you want. They would request it through the network and bundle it. This drives down technology costs as well.