TNE20003-Internet and Cybersecurity for Engineering Applications

What are the 3 types of personal data?

Volunteered, observed and inferred.

What is volunteered data?

Data that is created and explicitly shared by individuals

What is observed data?

data that is captured by recording the actions of individuals

What is inferred data?

data that is based on analysis of volunteered or observed data.

What is a bit?

0 or 1

How many bits in a byte?

8

What are three common methods of signal transmission used in networks?

Electrical signals, optical signals, wireless signals

What are electrical signals?

Transmission achieved by representing data as electrical pulses on copper wire.

What are optical signals?

Transmission achieved by converting the electrical signals into light pulses.

What are wireless signals?

Transmission is achieved by using infrared, microwave, or radio waves through the air.

Bandwidth is ___________.

the capacity of a medium to carry data

Bandwidth is typically measured in __________.

The number of bits that (theoretically) can be sent across the media in a second.

throughput is the measure of the transfer of bits across the media over a given period of time. However, throughput ______ match the specified bandwidth. This is due to ______.

does not usually | the amount of data being sent and received over the connection, the types of data being transmitted, the latency created by the number of network devices encountered between source and destination.

What are clients?

Clients are computer hosts that can request and display information obtained from a server.

What is a server?

Servers are hosts that have software installed which enable them to provide information

In a peer-to-peer network __________.

Devices function as both client and server

What are the advantages of P2P?

Easy to set up

less complex

lower cost

What are the disadvantages of P2P?

No central administration

not as secure as other networks

not scalable

slower performance

What do end devices do?

allow users to interact with the network

What is a network?

A combination of various networking devices and infrastructure which allows remote communication

All communications are governed by ______.

protocols

A standard is a ____________.

set of rules that determines how something must be done.

What do standards allow in networking?

different types of devices to send information to each other

HTTP governs the way _______________.

A web server and a web client interact

TCP is responsible for guaranteeing ___________.

the reliable delivery of information

IP is used by ______ to _____________.

routers

forward messages across multiple networks

Ethernet is responsible for _____________.

The delivery of messages from one Network Interface Card (NIC) to another NIC on the same Ethernet local area network (LAN)

What are the TCP/IP Model layers?

Network access, internet, transport, application.

In the TCP/IP Model, the network access layer _____, the internet layer _____, the transport layer _____ and the application layer _____.

Controls the hardware devices and media that make up the network

Determines the best path through the network

Supports communication between various devices across diverse networks

Represents data to the user, plus encoding and dialogue control

What are the OSI Model layers?

Physical, data link, network, transport, session, presentation, application

In the OSI Model, the physical layer is _____, the data link layer _____, the network layer _____, the transport layer _____, the session layer _____, the presentation layer _____ and the application layer _____.

the things we can see and touch

MAC-address related info

IP-address related info

checks speed/accuracy of data transfer

provides services to presentation layer

ensures data is presentable

supports process-to-process communication

MAC address is used at layer _, IP address is used at layer _.

2,3

What is the first octet range for a class A address?

0 - 125

What is the first octet range for a class B address?

128 - 191

What is the first octet range for a class C address?

192 - 223

What is the first octet range for a class D address?

224 - 239

A class A address has __ network bits, B has __ and C has __.

1, 2, 3

What is another way to describe a frame?

a Layer 2 Protocol Data Unit

What does a frame include?

the source and destination address

What is needed for a device to communicate on in an ethernet network?

Both physical and logical addresses

A physical address (_____) _____ change, a logical address (_____) _____ change

mac address, doesn’t, IP address, can

What does hierarchical network design provide?

Increased efficiency

optimisation of function

increased speed

a way in which to scale the network without impacting performance

What are the 3 layers of hierarchical network design?

Access, Distribution, Core

What do Access layer devices in hierarchical network design do?

provide connections to hosts in a wired or wireless network.

What does the Distribution layer of hierarchical network design do?

interconnects the smaller local networks.

What does the Core layer of hierarchical network design do?

provides a high-speed connection between distribution layer devices.

Messages through an ethernet hub must be sent _____ at a time.

One

How do hubs send and receive signals?

They take signals from one port and send the message out all of the other ports.

What is the purpose of an ethernet switch?

to provide micro-segmentation of the collision domain.

What is a content addressable memory (CAM) table

A table of MAC addresses

How does a switch build a CAM table

by examining a frame as it comes into the switch.

What are the steps a switch takes to build a CAM table?

adding the source MAC address of the device connected to the port the frame came from.

- forwarding a frame out to a specific port when the destination MAC address is in the MAC address table.

- forwarding a frame out to all hosts (except the sending host) when the destination MAC address is not in the MAC address table.

What happens if the destination MAC address is unknown?

the data needs to be broadcast.

What is a broadcast message used for?

to contact every other device on the local network.

An Ethernet broadcast is all _____ in the destination MAC address.

1s

What is a broadcast domain?

the area through which a broadcast message can travel.

What are routers used to do in broadcast domains?

to divide the network into multiple broadcast domains.

What must a device do to send information from a device that is on an Ethernet network

supply a source and destination MAC and IP address

What is used to discover the MAC address of a device on the same local network?

The address resolution protocol (ARP)

What are the three steps ARP uses?

The sending broadcasts a frame containing a message with the IPv4 address of the intended destination host.

Each host on the network receives the broadcast frame and compares the IPv4 address contained in the message with its own IPv4 address.

The host with the matching IPv4 address sends its own MAC address back to the original sending host.

The sending host receives the message and stores the MAC address and the IPv4 address in an ARP table.

What are the 4 main purposes of routers?

broadcast containment, security, interconnecting local networks, logically grouping users

What is the ARP process?

Mapping a known IP Address to an unknown MAC Address.

For Network transmission to function as efficiently as possible __________.

all data that moves through a network needs both MAC and IP Addresses.

What does a routing table contain?

network addresses and the best path to reach a network.

Routers _____ forward broadcast messages.

do not

What does a routing table do with the destination IP address?

It is compared with the networks in the routing table to determine the interface to forward the packet out of.

What does a routing table do with the destination MAC address?

It is used to forward the packet to either the router if the destination IP address is for a different network or a specific network device on the local network.

What are the 2 ways routes can be added to the routing table?

Dynamically learned from other routers

Manually entered by a network administrator

What is a default route?

The router interface used when forwarding packets to a destination that is not in the routing table.

If a packet is destined for a network that is not in the routing table and no default route exists _____.

the packet will be dropped

When a host sends a message to a device on the same network, __________.

it forwards the message directly and uses ARP to discover the MAC address.

When a host sends a message to a device on a remote network, __________.

the hosts uses the MAC address of the Router as the destination, but still has the IP address of the remote host as the Layer 3 destination.

What are the advantages of a single local segment?

Appropriate for simpler networks

less complexity and lower network cost

allows devices to be "seen" by other devices

faster data transfer - more direct communication

ease of device access

What are the disadvantages of a single local segment?

All hosts are in one broadcast domain which causes more traffic on the segment and may slow network performance

harder to implement QoS

harder to implement security

What are the advantages of having hosts on a remote segment?

More appropriate for larger, more complex networks

Splits up broadcast domains and decreases traffic

Can improve performance on each segment

Makes the machines invisible to those on other local network segments

Can provide increased security

Can improve network organization

What are the disadvantages of having hosts on a remote segment?

Requires the use of routing

Router can slow traffic between segments

More complexity and expense

What 2 protocols does TCP/IP use in the transport layer

Transmission Control Protocol and User Datagram Protocol

What are the responsibilities of transport layer protocols?

Tracking the individual communication between applications on the source and destination hosts

segmenting data for and reassembling segmented data at the destination

identifying the proper application for each communication stream

What are the responsibilities of the transport layer?

tracking individual conversations

segmenting and reassembling data

adding header information

identify, separate and manage multiple conversations

What does URL stand for and do?

Uniform Resource Locator

defines the network location of a specific resource on the network

What does URN stand for and do?

Uniform Resource Name

identifies the namespace of the resource without reference to the protocol

What are the properties of UDP?

Fast but prone to data loss

What are the properties of TCP?

slower, but prioritises reliability

acknowledges data

resends lost data

delivers data in order sent

What 4 protocols are necessary to deliver a webpage function at the internet, transport and application layers, respectively?

IP, TCP, HTTP

What do TCP and UDP use port numbers for?

to manage multiple, simultaneous conversations

what is source port number associated with?

the originating application on the local host

what is destination port number associated with?

the destination application on the remote host

What are sequence number used for?

To reassemble segments into their original order

What optional TCP procedure do host OS’ usually use during the three-way handshake?

selective acknowledgement (SACK)

What happens if 2 hosts use SACK?

the receiver can explicitly acknowledge which bytes were received during any discontinuous segments.

What is UDP used for?

applications that can tolerate a small loss of data but cannot tolerate delay

What are some examples of things UDP is used for?

video calls

livestreams

Online Games

In what 2 ways are IP addresses assigned?

statically or dynamically

How are static IP addresses configured?

Manually

What are static IPs used for?

devices that need a fixed IP

Why are static IPs prone to errors?

human error during configuration

How are dynamic IP addresses assigned?

automatically through DHCP

What does DHCP stand for?

Dynamic Host Configuration Protocol

What are the benefits of dynamic addressing?

reduced human error, IP addresses aren’t permanent

What happens when dynamic IPs aren’t being used?

they go back into the pool