Networking Fundamentals (1) Flashcards

1
Q

What is a network

A

Two or more computers connected together

Computers can be any type of computing device (IPSO)

Can be wired or wireless

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2
Q

Why have a network?

A

Share data, remote communication, share resources, such as printers, DBs

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3
Q

How computers communicate on a network, what is needed on both sides?

A

Applications that wish to communicate with one another
Common protocol
Network Interface to connect to network
Transmission media (wired/wireless)

Diagrams page19

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4
Q

Client / Server communication

A

Client initiates the connection
Server waits for clients to connect (has the option to accept or deny)

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5
Q

Explain P2P connections

A

No dedicated server, both clients act as client and server

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6
Q

What is an IP Address

A

Number that identifies a node on the network

e.g.
IPv4 - 192.168.1.10
IPv6 - 2601:140:8780:43f0:2d1e:9ebb:92f0:d6e9

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7
Q

Explain MAC Addresses

A

Physical address of the network interface
Cannot be changed and is assigned by the NIC vendor

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8
Q

Unicast

A

Data being sent to one device

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9
Q

Multicast

A

One to some

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10
Q

Broadcast

A

One to all

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11
Q

What is a protocol

A

Set of rules or “language” for communication
A host will use several protocols to make a connection on the network

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12
Q

What is a port

A

Number that represents an application on the network

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13
Q

What is a socket

A

A port that is in use
Unique combination of protocol, IP address and port

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14
Q

Provide an example of a socket

A

TCP 192.168.1.5:80

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15
Q

How many layers in the OSI Model

A

7

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16
Q

OSI Model layer 1

A

Physical

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17
Q

What is Protocol Data Unit (PDA)?

A

Specific block of information transferred over a network

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18
Q

PDU OSI Layer types

A

◦ Application = data
◦ Presentation = data
◦ Session = data
◦ Transport = segment (TCP), datagram (UDP)
◦ Network = packet
◦ Data Link = frame
◦ Physical = bit

19
Q

OSI Layer 7 : Application Layer

A

The application itself, where users are typically provided a gui

A protocol is agreed on
e.g. SMTP, HTTP, RDP, TFTP, etc.

20
Q

Layer 6 : Presentation

A

Both sides agree on a common data format, application might request a browser plugin to be installed here
e.g. JPG, MP3, MP4, PDF, etc.

21
Q

Layer 5 : Session

A

Keeps seperate conversation seperate
Ports are usually assigned to the conversation

22
Q

Layer 4 : Transport

A

TCP / UDP Utilised

TCP:
Breaks up data into manageable pieces for transmission
◦ Adds sequence numbers to each segment for reassembly at other end
◦ Embeds the source and destination ports into its header
◦ Establishes the session with a handshake
◦ Provides error correction and flow control during session
◦ Tears down session with a handshake

UDP:
◦ Embeds the source and destination ports into its header
◦ Depends on the application for session establishment, management, payload length, error correction,
flow control, and tear down

23
Q

Layer 3 : Network

A

Adds a logical address, usually IP address
Chooses optimal route

24
Q

Layer 2 : Data Link Layer

A

Adds a physical source and destination address
Adds both a header and trailer
Checks incoming frames for errors, cyclical redundancy check (CRC)

25
Q

What are Layer 2s Two Sub Layers

A

Logical Link Control (LLC) : Describes the layer 3 payload
Media Access control (MAC) : Adds the physical address

26
Q

Layer 1 : Physical

A

Actual transmission of 1s and 0s
All electrical and mechanical aspects of transmission

e.g. Hubs, repeaters, rj45 connectors

27
Q

Data encapsulation and Decapsulation

A

Encapsulation
Layers 4, 3, 2 on the sender add a header
◦ Description of the data and/or protocol
◦ Layer 2 also adds a trailer
Decapsulation:
Corresponding layers on the receiver remove the header
◦ Refer to the information in the header/trailer
◦ Pass the PDU up to the next layer

28
Q

OSI Encapsulation / Decapsulation Diagram page

A

Page 55

29
Q

What is the DoD Model

A

Developed by the US department of defense
4 Layer model
Referred to as TCP/IP Model

30
Q

DoD Model Layers (Top to bottom)

A

Application, Host to Host, Internet, Network Access

31
Q

DoD Model core protocols

A

TCP,UDP,IP,ICMP,IGMP,ARP

32
Q

Which is the only protocol in the DoD that doesn’t have an IANA assigned protocol number?

A

ARP

33
Q

DoD Model Application Layer Contains

A

Data Payload

34
Q

DoD Model Host to Host Layer Contains

A

Session establishment / Management
Sequencing

35
Q

DoD Model Internet Layer Contains

A

Logical Addressing
Routing

36
Q

DoD Model Network Access Layer Contains

A

Physical addressing, Framing/CRC/MTU
Actual Transmission

37
Q

Purpose of a connection oriented protocol

A

Attempts to ensure reliability and completeness

Typically found used in application like video games

38
Q

Purpose of a connectionless protocol

A

Makes no attempt to ensure completeness of transmission

Typically found in application like streaming services

39
Q

Connection Oriented vs Connectionless
Protocols

P63 for diagram

A

Connection Oriented: TCP
Connectionless: UDP, IP, ICMP, IGMP, ARP

40
Q

What is the difference between connection oriented vs connectionless when regarding performance

A

Connection oriented prioritises reliability whereas connectionless goes for speed/performance

41
Q

TCP Flags

A

URG, ACK, PSH, RST, SYN, FIN

42
Q

What does each TCP Flag mean

A

URG: Tells receiver to prioritise the data
ACK: Acknowledge
PSH: Tells receiver to directly send this data to the application
RST: Tells receiver that the sender has abruptly ended the connection
SYN: Used in 3way handshake to start conversation
FIN: Used in the 4way handshake to end the conversation

43
Q
A