week 5 local area networks Flashcards
What is CSMA/CD?
CSMA/CD (Carrier Sense Multiple Access with Collision Detection) is a protocol used to manage how devices share a communication medium (like Ethernet) to prevent data collisions.
What is the main concept behind CSMA/CD?
CSMA/CD: Devices listen to the network before transmitting, and if a collision is detected during transmission, both devices stop and wait a random time before retransmitting.
What is a Network Interface Card (NIC)?
A NIC is a hardware component that connects a device to a network and handles sending/receiving data packets.
What is a MAC address?
A MAC address is a unique 48-bit identifier assigned to a NIC, written in hexadecimal format (e.g., 00:60:8C:00:54:99).
What are the key differences between Hubs and Switches?
Hubs broadcast data to all devices and cause more collisions, while switches send data to the intended recipient, reducing collisions.
What are the types of Ethernet transmission?
Types of Ethernet transmission:
Unicast (one-to-one)
Multicast (one-to-many)
Broadcast (one-to-all)
What is the role of the Data Link Layer in networking?
The Data Link Layer is responsible for framing, error detection, and MAC addressing.
What is the IEEE 802.3 standard?
IEEE 802.3 is the standard for Ethernet.
What is a Virtual LAN (VLAN)?
A VLAN is a software-defined network that groups devices logically, regardless of their physical location, improving network performance and security.
What is Power over Ethernet (PoE)?
Power over Ethernet (PoE) is a technology that allows Ethernet cables to deliver both power and data to devices like wireless access points, IP phones, and security cameras.
What is the difference between Shared Media and Switched Media?
Shared Media means all devices share the same medium, leading to collisions. Switched Media provides dedicated paths for devices, reducing collisions.
What is a Collision Domain?
A Collision Domain is a network segment where data packets can collide if two devices transmit at the same time. Switches reduce collision domains by isolating traffic.
What is a Broadcast Domain?
A Broadcast Domain is a network segment where a broadcast packet is forwarded to all devices. Routers separate broadcast domains to reduce unnecessary traffic.
What are the two types of addresses used in networking?
MAC Address (Layer 2) is used within the local network, and IP Address (Layer 3) is used across different networks.
What is Unicast?
Unicast is a one-to-one communication, where data is sent to a specific device on the network.
What is Multicast?
Multicast is one-to-many communication, where data is sent to a group of devices, but not all devices on the network.
What is Broadcast?
Broadcast is one-to-all communication, where data is sent to all devices within a broadcast domain.
How does CSMA/CD work in detail?
CSMA/CD: A device listens to the network to check if it’s free. If free, it starts transmitting; if a collision occurs, both devices stop, wait for a random backoff time, and retransmit.
What are the benefits of VLANs?
VLANs reduce broadcast traffic, increase security, and provide network flexibility by logically grouping devices, regardless of physical location.
What are the two sub-layers of the Data Link Layer?
Logical Link Control (LLC): Manages flow control and error checking.
Media Access Control (MAC): Handles addressing and controls access to the physical medium.
What is the standard for Power over Ethernet (PoE)?
The standard for Power over Ethernet (PoE) is defined in IEEE 802.3af.
What are the two main types of NICs?
- Wired NIC: Connects to the network using Ethernet cables.
- Wireless NIC: Connects to the network using Wi-Fi.
What are the two parts of a MAC address?
First 24 bits: Organisationally Unique Identifier (OUI), assigned by the IEEE.
Last 24 bits: Device-specific identifier assigned by the manufacturer.
How can you find a MAC address on a computer?
Windows: ipconfig /all
Linux/Mac: ifconfig
What is an example of a broadcast transmission?
ARP (Address Resolution Protocol) requests use broadcasts to find MAC addresses on a network.
What are the two sub-layers of the Data Link Layer?
Logical Link Control (LLC): Manages flow control and error checking.
Media Access Control (MAC): Handles addressing and controls access to the transmission medium.
What are the different ways to group devices into VLANs?
By switch ports.
By MAC addresses.
By Layer 3 protocol types (e.g., IP).
What devices commonly use Power over Ethernet (PoE)?
Wireless Access Points (WAPs).
IP phones.
Security cameras.
What is the main purpose of VLANs?
VLANs reduce broadcast traffic, improve network security, and provide flexibility in network configuration.
What is the standard that defines Power over Ethernet (PoE)?
IEEE 802.3af.
What is an example of a shared media network device?
Hubs are an example of shared media network devices.
What is an example of a switched media network device?
Switches are an example of switched media network devices.
How do switches reduce collision domains?
Switches isolate traffic between ports, creating separate collision domains for each port
How do routers reduce broadcast domains?
Routers separate broadcast domains, preventing broadcast packets from being sent to all devices on the network.
What are the three types of data transmission on a network?
Unicast: One-to-one communication.
Multicast: One-to-many communication.
Broadcast: One-to-all communication within a broadcast domain.
What does the IEEE 802.11 standard refer to?
The IEEE 802.11 standard refers to Wi-Fi.
What does the IEEE 802.1Q standard refer to?
The IEEE 802.1Q standard refers to VLANs.
What are standards?
Rules set by organisations like IEEE to ensure devices from different manufacturers can work together on a network.
What is a medium in networking?
A medium is the physical path through which data travels, like cables (wired) or radio waves (wireless).
Why are collisions bad
Wasted Bandwidth: Collisions cause data to be retransmitted, using up more bandwidth.
Delays in Data Transfer: Devices must wait a random amount of time before trying to send data again (backoff time), slowing down the network.
Higher Collision Rate = Lower Network Performance: If too many collisions occur, the network slows down significantly.
