Questions and Answers
What is a computer network?
What type of network connects devices over a larger geographical area?
What is the difference between physical and logical topology?
What protocol is used for transferring data over the web?
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What is the function of a switch in a network?
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What is the function of a router in a network?
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What is the purpose of the physical layer in a network?
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What is the function of the network layer in a network?
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Which OSI layer is responsible for routing data between networks?
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What is the equivalent layer in the TCP/IP model to the OSI's Network Layer?
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Which security feature filters incoming and outgoing traffic based on source IP, destination IP, port numbers, and protocols?
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What is the primary goal of router hardening?
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Which OSI layer is responsible for providing error-free transfer of data frames?
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What is the purpose of changing default passwords on a router?
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Which of the following is NOT a security feature used to secure routers?
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What is the purpose of regularly updating router firmware?
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What is the primary layer that connects devices to the network in a hierarchical architecture?
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Which switch fabric architecture is known for its high-speed switching capabilities?
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What is the primary mode of switching where the switch stores the entire packet before forwarding it?
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In which network topology do devices connect in a circular configuration, providing redundancy and fault tolerance?
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What is the function of the distribution layer in a hierarchical architecture?
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Which switch fabric architecture is limited in scalability due to a single shared bus?
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What is the primary advantage of the cut-through switching mode?
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In which topology does a central switch connect to multiple devices?
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Study Notes
Definition and Types
- A computer network is a collection of interconnected devices that communicate with each other to share resources and exchange data.
- Types of computer networks:
- LAN (Local Area Network): connects devices in a limited geographical area (e.g., home, office building).
- WAN (Wide Area Network): connects devices over a larger geographical area (e.g., city, country).
- MAN (Metropolitan Area Network): connects devices in a metropolitan area (e.g., city, town).
- WLAN (Wireless Local Area Network): connects devices wirelessly in a limited geographical area.
- VPN (Virtual Private Network): connects devices securely over the internet.
Network Topologies
- Physical Topology: the physical layout of devices in a network (e.g., bus, star, ring).
- Logical Topology: the way data is transmitted between devices in a network (e.g., bus, star, ring).
Network Protocols
- TCP/IP (Transmission Control Protocol/Internet Protocol): a suite of protocols used for communicating over the internet.
- HTTP (Hypertext Transfer Protocol): a protocol used for transferring data over the web.
- FTP (File Transfer Protocol): a protocol used for transferring files over a network.
- SMTP (Simple Mail Transfer Protocol): a protocol used for sending and receiving emails.
Network Devices
- Hub: a simple network device that connects multiple devices together.
- Switch: a network device that connects multiple devices together and filters traffic.
- Router: a network device that connects multiple networks together and routes traffic.
- Gateway: a network device that connects a network to the internet.
Network Layers
- Physical Layer (Layer 1): defines the physical means of data transmission.
- Data Link Layer (Layer 2): provides error-free transfer of data frames.
- Network Layer (Layer 3): routes data between networks.
- Transport Layer (Layer 4): provides reliable data transfer between devices.
- Session Layer (Layer 5): establishes, maintains, and terminates connections.
- Presentation Layer (Layer 6): converts data into a format that can be understood by the receiving device.
- Application Layer (Layer 7): provides services to end-user applications.
Network Security
- Firewall: a network device that filters incoming and outgoing traffic based on security rules.
- Encryption: the process of converting plaintext data into unreadable ciphertext.
- Authentication: the process of verifying the identity of a user or device.
- Authorization: the process of granting access to resources based on a user's identity.
Definition and Types
- A computer network is a collection of interconnected devices that communicate with each other to share resources and exchange data.
- There are five types of computer networks: LAN, WAN, MAN, WLAN, and VPN.
Network Topologies
- Physical Topology refers to the physical layout of devices in a network, and can be bus, star, or ring.
- Logical Topology refers to the way data is transmitted between devices in a network, and can also be bus, star, or ring.
Network Protocols
- TCP/IP is a suite of protocols used for communicating over the internet.
- HTTP is a protocol used for transferring data over the web.
- FTP is a protocol used for transferring files over a network.
- SMTP is a protocol used for sending and receiving emails.
Network Devices
- A Hub is a simple network device that connects multiple devices together.
- A Switch is a network device that connects multiple devices together and filters traffic.
- A Router is a network device that connects multiple networks together and routes traffic.
- A Gateway is a network device that connects a network to the internet.
Network Layers
- The Physical Layer (Layer 1) defines the physical means of data transmission.
- The Data Link Layer (Layer 2) provides error-free transfer of data frames.
- The Network Layer (Layer 3) routes data between networks.
- The Transport Layer (Layer 4) provides reliable data transfer between devices.
- The Session Layer (Layer 5) establishes, maintains, and terminates connections.
- The Presentation Layer (Layer 6) converts data into a format that can be understood by the receiving device.
- The Application Layer (Layer 7) provides services to end-user applications.
Network Security
- A Firewall is a network device that filters incoming and outgoing traffic based on security rules.
- Encryption is the process of converting plaintext data into unreadable ciphertext.
- Authentication is the process of verifying the identity of a user or device.
- Authorization is the process of granting access to resources based on a user's identity.
Network Architecture
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OSI Model: A 7-layered framework for network communication
- Layer 1: Physical layer defines physical means of data transmission (e.g., Wi-Fi, Ethernet)
- Layer 2: Data Link layer provides error-free transfer of data frames between nodes on the same network
- Layer 3: Network layer routes data between networks (e.g., IP addressing, routing protocols)
- Layer 4: Transport layer provides reliable data transfer between devices (e.g., TCP, UDP)
- Layer 5: Session layer establishes, manages, and terminates connections between applications
- Layer 6: Presentation layer converts data into a format for transmission (e.g., encryption, compression)
- Layer 7: Application layer supports functions such as email, FTP, and HTTP
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TCP/IP Model: A 4-layered framework for network communication
- Layer 1: Network Access layer combines OSI's Physical and Data Link layers
- Layer 2: Internet layer routes data between networks (equivalent to OSI's Network layer)
- Layer 3: Transport layer equivalent to OSI's Transport layer
- Layer 4: Application layer equivalent to OSI's Session, Presentation, and Application layers
Router Configuration
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Router Security: Measures to secure routers and prevent unauthorized access and attacks
- Access Control Lists (ACLs): Filter traffic based on source IP, destination IP, port numbers, and protocols
- Firewall Configuration: Block or allow traffic based on predetermined security rules
- Authentication, Authorization, and Accounting (AAA): Verify user identities, grant access, and track network activity
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Router Hardening: Securing router configurations to prevent attacks
- Disable Unnecessary Services: Turn off unused services and features to reduce attack surface
- Change Default Passwords: Replace default passwords with strong, unique passwords
- Limit Access: Restrict access to the router's configuration interface to authorized users
- Regularly Update Firmware: Ensure router firmware is up-to-date to patch security vulnerabilities
Network Architecture
Hierarchical Architecture
- A network switch follows a hierarchical architecture consisting of three layers:
- Access Layer connects devices to the network, such as computers and printers.
- Distribution Layer aggregates multiple access layer switches and connects to the core layer.
- Core Layer provides high-speed connectivity between distribution layers and connects to other networks.
Switch Fabric Architecture
- Switch fabric is the internal architecture of the switch, responsible for forwarding packets between ports.
- Common switch fabric architectures include:
- Shared Bus has a single bus shared among all ports, limiting scalability.
- Shared Memory uses a shared memory buffer to store packets, allowing for better performance.
- Crossbar is a matrix of paths connecting input and output ports, enabling high-speed switching.
Switching Modes
- Network switches operate in two primary modes:
- Store-and-Forward stores the entire packet before forwarding it to the destination port.
- Cut-Through begins forwarding the packet as soon as it receives the destination MAC address.
Network Topology
- Network switches can be connected in various topologies, including:
- Star Topology has a central switch connecting to multiple devices.
- Mesh Topology connects each device to every other device, providing redundancy and fault tolerance.
- Ring Topology has devices connected in a circular configuration, with data traveling in one direction.
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Description
This quiz covers the definition and types of computer networks, including LAN, WAN, and MAN. Test your knowledge of these interconnected devices that share resources and exchange data.
