1
Q
What are the four layers of the DoD TCP/IP Model?
A
- Network Access
- Internet
- Transport
- Application
remember ATIN
2
Q
What is the primary purpose of the OSI model?
A
To standardize the functions of a telecommunication system for interoperability, scalability, security, and efficiency.
3
Q
What does the Network Layer do in the OSI model?
A
It manages routing and logical addressing of data across networks. It uses IP addresses to uniquely identify sending and receiving devices
4
Q
Define MAC Address and its role.
A
A MAC (media access control) address is a unique hardware identifier assigned to network interfaces at the data link layer used for communication on the local network
5
Q
What is the main function of the Internet Layer in the DoD model?
A
Handles packaging, addressing, and routing of data; corresponds to OSI’s Network Layer.
6
Q
List the seven layers of the OSI model.
A
- Application
- Presentation
- Session
- Transport
- Network
- Data Link
- Physical
remember: please do not throw sausage pizza away
7
Q
How do switches use MAC addresses for layer 2 switching?
A
- make decisions on how to forward data packets between devices on the same network
- the mechanism of the action is learning, forwarding and filtering
8
Q
What protocols operate at the Transport Layer?
A
TCP and UDP
9
Q
What are the two primary purposes of an IP address?
A
- Network interface identification
- Location addressing
10
Q
What is the purpose of the Application Layer (Layer 7) in the OSI model?
A
- facilitates interaction between software applications and network
- manages how data is presented to the user and manages user input
- provides the interface
Protocols include HTTP, SMPT, DNS
11
Q
What is the function of the Presentation Layer (Layer 6)? OSI
A
- ensures data is transferred through the network in a suitable format
- converts data from an application format into a network format and vice versa
Protocols include ACSII, JPEG, MPEG
12
Q
What does the Session Layer (Layer 5) do? OSI
A
- establishes, manages and terminates the connections (sessions) between local and remote applications
- introduces checkpoints into data stream, which can be used for recovery
Protocols include CHAP, PAP, RPC
13
Q
What is the role of the Transport Layer (Layer 4)? OSI
A
- ensures the data is transferred reliably without any errors through error detection
- breaks down large data files into smaller segments
Protocols include TCP, UDP
14
Q
network layer (layer 3) osi model
A
- manages routing of data packets across complex networks
- uses IP addresses to uniquely identify sending and receiving devices
- breaks packets into smaller fragments
Protocols include IP, ICMP, BGP
15
Q
What does the Data Link Layer (Layer 2) manage? OSI
A
- handles error-free transfer of data packets
- adds MAC addresses to frames
Protocols include ethernet, wifi and PPP
16
Q
What is the responsibility of the Physical Layer (Layer 1)? OSI
A
- converts digital bits into electrical signals
Protocols include USB, Bluetooth, ethernet, DSC
17
Q
what is the function of the application layer (layer 4) dod model?
A
- enables the user to interact with the app or network
- handles encryption and description and coordinates conversations between applications and includes authentication and reconnection
Protocols include HTTP, SMTP, POP, FTP, HTTPS etc.
18
Q
what is the function of the transport layer of the dod model (layer 3)
A
- transfers data across a network
- determines how much data to send, to where and at what rate
- encapsulates data by adding header to the piece, called data segments
Protocols include TCP and UDP
19
Q
what is the function of the internet layer of dod (layer 2)
A
- handles packaging, addressing, and routing of data
- this is where IP addresses are applied for routing purposes
Protocols include ARP, IP etc
20
Q
what is the function of the network layer (layer 1) dod
A
- handles moving data into and out of a networks physical link and handles problems resulting from bit transmission errors
- responsible for transporting data using electrical, mechanical or procedural interfaces
Protocols include network medium and NIC
21
Q
what are ip addresses and how do they work with layer 3 routing
A
- unique identifier assigned to each device connected to a computer network
- the purpose is a network interface identification and location addressing
Layer 3 routing - transferring data packets from one network to another, which occurs at network layer
22
Q
what is a protocol
A
- set of rules and conventions that govern communication between devices over a network
- they define the procedures and formats that devices must follow to perform tasks
- operate at various layers of networks
23
Q
what is the role of UDP
A
- user datagram protocol (UDP) is a protocol used to transmit information across a network without prior communication
- some characteristics include speed and simplicity, no error recovery, unreliable delivery and non-sequential, broadcasting
- doesn’t establish a connection before sending data, so data packets (datagrams) can be sent anytime without formal handshakes
- speeds up data sending process by sending packets without making any agreement and recipient has to make sense of data
- includes checksum but is optional
- header length is fixed, exactly 8 bytes
24
Q
what is the role of TCP
A
- transmission control protocol (TCP) provides a reliable, ordered, and error-checked delivery of a stream of data
- key characteristics include reliability, ordered data transfer, error checking, flow control and congestion control
- works by using a ‘three way handshake’
1. client device initiates data transfer and sends a sequence number (SYN)
2. server acknowledges the SYN and sends its own SYN number (SYN-ACK)
3. client acknowledges the servers SYNACK so therefore ACK - requires a connection between two endpoints so best for emails and texting, file transfers and web browsers
25
what are network packets
- unit of data being transmitted across a network
- consists of a header - metadata about the packet and payload - the data the packet is transporting
26
what are the different network packets and data encapsulation
Bits - layer 1
Frame - layer 2
Packet - layer 3
Segments - layer 4
*remember big fat protocol sandwich
27
what is TCP/IP
- Transmission control protocol/internet protocol is a core set of protocols that define the internet
- some core functions include routing, addressing, error detection and handling and interface to applications
28
what is an IP address
- internet protocol address is used to transmit data across different network
- some features are addressing, routing, and packetisation
29
what is IPv4 and IPv6
IPv4
- an IP address with a 32 bit (4 bytes) number
- there are 4.3 billion addresses which use DHCP and manual configuration
IPv6
- increases the number of IP addresses by increasing the size to 128 bits
- offers more functionality and supports auto configuration
30
what are public and private IP addresses
Public
- globally unique IP addresses assigned to a device
- used by routers that need to be directly accessible from the internet
Private
- not globally unique and are set aside for use within private network
- they are only visible in the LAN
31
what is NAT
- network address translation (NAT) translates private IP addresses within a local network to a public IP address
32
what are classes of IP addresses
Class A - supports very large networks, first octet for network identification, remaining 3 for host
Class B - medium sized networks, two octets network, two host
Class C - smaller SOHO networks, three network, one host
Class D - multi-cast groups
Class E - reserved for future/experimental purposes
33
what is subnetting and why is it used
- subnetting is the process of dividing larger networks into smaller networks
- it is used to reduce the size of a broadcast address
34
what are subnet masks and how do you subnet
- subnet masks are used to identify the host and network portions of an IP address
Process
1. Convert into binary
2. Replace network portion with 1s and host portion with 0s
3. Convert binary into decimal notation
35
what is a strategy for administrators for IP addressing
1. assess network requirements - size of network, growth potential, and type of devices
2. determine network segmentations - subnetting, VLANS
3. choose between IPv4 and IPv6
4. IP address allocation strategy
-> static IP - IP address assigned to a device and remains constant
-> dynamic IP - temporary address assigned to device
36
what is the role of the default gateway
- is a device (router) that connects devices together
- IP routing - if a device wants to talk to a device on a different subnet, the default gateway is used
- connectivity facilitator - acts as gateway from LAN to WAN
- used in subnetting
37
what is the role of DNS
- domain name system (DNS) translates human-friendly domain names into IP addresses
How does it work?
- DNS query
- recursive resolution
- response
38
what are the role of ports
- enables communication between different applications on a network
- multiplexing and demultiplexing
39
what are the two types of copper cables
1. twisted pair
2. coaxial cable
40
describe the structure, types and advantages of a twisted pair cable
Structure - consists of pairs of insulated copper wires twisted together to reduce EMI and crosstalk
Types - unshielded twisted pair (UTP) used in ethernet networks and telephone systems
- shielded twisted pair (STP) includes a shielding layer to minimise interference further
Advantages - cost effective, easy to install and maintain, suitable for short to medium distances
41
describe the structure, uses and advantages of a coaxial cable
Structure - features central copper conductor surrounded by insulation, a metallic shield and outer protective jacket
Use - transmit video signals from sources to displays
Advantages - durability, signal quality and longer distance support
42
describe the structure, uses and advantages of a fibre optic cable
Structure
Core - ultra-thin glass that carries light signals
Cladding - surrounds the core with material of lower refractive index
Protective coating - shields delicate fibres
43
describe the function of wifi
- go to solution for wireless LAN's, as users move freely within network range while staying connected
- variety of speeds, coverage areas and capabilities and can easily be expanded
44
describe the function of bluetooth
- used in PAN's, connects devices for up to 10 meters
- used for connecting peripherals to devices with low power consumptions
45
what is a network interface card, what are the functions and types of it
- a network interface card (NIC) allows computers to connect to a network
- the functions are data conversion, physical connections and MAC address data framing
- some of the types include wireless, wired and virtual
- operates at data link layer
46
what is a hub
- connects multiple network devices within a physical layer of OSI model
- simple repeater, limited bandwidth and all devices connected to hub share the same collision domain.
- inheriently insecure, making them vulnerable to eavesdropping and security breaches
- rarely used in modern networks due to limitations and security
47
what is a switch
- connects multiple devices together on a network, on the data link layer
- intelligently forwards data frames, based on MAC addresses
- each port on switch represents a separate collision domain with increased bandwidth
- offers high level security as only directs data to intended recipient
- more dominant and has advanced features, like VLAN's, quality of service and spanning tree protocol
48
explain the relationship between switches and advanced resolution
- ARP requests and responses
- building MAC address tables
- broadcasting within the network segment
- reduce broadcast traffic
49
what is switch layering
- organising switches into different layers based on functions and roles
- three main layers are access, distribution and core layer
- each layer plays specific role in managing traffic flow, implementing VLAN's and subnet masking
50
describe the 3 layers of switch layering
Access
- lowest point in switch hierarchy and is closed to end devices
- responsible for connecting end devices to a network
- key functions of port-based VLAN assignment and traffic filtering and security
Distribution
- middle layer, sometimes not needed in smaller systems
- allows communication between different VLAN's
- key functions are inter VLAN routing, implementing security policies and access control and redundancy and load balancing
Core
- highest layer and serves as backbone
- handles high speed traffic routing
- key functions are high speed packeting switching and routing, and applying advanced security measures
51
what is switch layering
Layer 2 switching
- operates and layer 2 layer which use MAC addresses to forward frames within the LAN
Layer 3 switching
- operates at network layer and uses IP addresses to make forwarding decisions and can route traffic
52
what are VLAN's
- virtual local area network (VLAN's) are subdivisions of a physical network that group devices together based on factors
- they assign switch ports to specific VLAN's ID
- benefits include improved network performance, enhanced security and increased flexibility
53
what is subnet masking
- the process of dividing a network into smaller subnets
- benefits include efficient allocation of IP addresses, reduced network congestion
The combinations of VLANs and subnet masking enables
-> traffic control and security policies
-> efficient utilisation of IP addresses
-> scalability and flexibility in network design
54
what are routers
- forwards data packets
- determines optimal path for data packets to reach their destination
- key features include routing tables, routing protocols, interfaces and security features, such as firewalls and access control list (ACL's) to filter traffic
- optimises data flow, minimising delays and maximising network performance
Types
- home - home networks
- enterprise - designed for larger organisations
- edge - sit at edge of network and connects it to other networks
- core - high-performance routers which handle large volumes of traffic
- primarily works at layer 3 (network) but also interacts with layer 2 (data link)
55
what is layer 3 routing
Layer 3 routing
- forwarding data packets between different networks
- works by packet forwarding (generates packet that contains destination IP address of receiving device), routing table lookup (sending device checks routing table to determine next hop or router to send packet), routing decision (sending devices selects appropriate route from its routing table)
56
what are gateways
- connects two or more distinct networks together, enabling them to communicate and exchange data
Key roles
1. protocol translation
2. addressing conversion
3. inter network routing
4. network segmentation
5. firewall and security
- operates and network layer (3)
57
what are firewalls, their types and benefits
- security system designed to prevent unauthorised access into a computer network
- it examines data packets and determines whether to block or allow it
Types
- packet filtering - examines individual packets and compares them against a set of rules
- stateful inspection - tracks the state of network connections and makes decisions
- primarily operates at transport and application layers
Benefits include preventing unauthorised access, controls network traffic and malware protection
58
what are WAPs
- wireless access points are devices that allows wireless devices to connect to a wired network
- uses specific frequencies and protocols
- transmits wireless signals to and from wireless devices
- manages connections from multiple wireless devices simultaneously
- operates at data link layer and physical layer
59
what is a network topology and the factors that affect choosing network topologies
- arrangement of various elements within a network
- designing a network topology that balances security and performance requires careful consideration of factors
Network segmentation - subnetting and VLAN's
Layered security approach - perimeter, internal and data security
Redundancy and high availability - device redundancy, link redundancy and load balancing
Network design considerations - centralised vs decentralised, hierarchical design and star, bus or mesh topologies
Security best practices - strong authentication and access control, regular security updates and patching, security monitoring and logging
Performance optimisation techniques - QoS, traffic shaping and caching and content delivery networks (CDN's)
Network management tools - network monitoring software, configuration management tools and security information and event management
60
what are the types of network topologies
Bus - connects all devices to a single cable
Ring - devices are connected in a closed loop
Star - central device connecting others together
Mesh - every device is connected to all other devices
Tree - looks like a family tree
61
what is bandwidth, the significance of it and designing for optimal bandwitdth
- maximum amount of data that can be transmitted over a network
- directly influences speed, responsiveness and overall performance
- significance is user experience - slow bandwidth leads to frustrations and decreased productivity - cost efficiency - inadequate bandwidth causes decreased productivity which leads to financial loss
- designing for optimal bandwidth - needs assessment, traffic analysis, segmentation strategies, QoS, monitoring optimisation
62
what is a collision domain and the benefits
- data packets collide due to multiple devices attempting to transmit simultaneously over the same medium
- subnetting reduces collision domains
- benefits of reducing collision domain include reduced congestion, minimised collisions, faster transmission, lower latency and scalability
63
what is a broadcast domain and their benefits
- network segment where any device sending broadcast message will have the message delivered to all other devices
- confined to layer 2 network
- excessive broadcast traffic leads to network congestion
- benefits include improved performance, enhanced security and efficient resource utilisation
64
what are some tools for visualising bandwidth
- network mapping software and bandwidth monitoring tools
65
what are tools for network performance management and troubleshooting
Ping - sends ICMP echo request packet to target device and waits for reply. Limitations include its basic functionality and firewall restrictions
Trace routing - traces the path data packets take across the internet. It detects network bottlenecks and latency issues. Helps identify where the problem lies
computer science
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