LANs and MAC Techniques Flashcards
(14 cards)
What is a Local Area Network (LAN)?
A LAN is a network that connects computers and devices within a limited area such as a home, school, or office. It allows sharing of resources like files, printers, and internet connections.
What are the key characteristics of a LAN?
LANs cover a small geographic area, offer high data transfer rates, use private IP addresses, and are typically owned and maintained by a single organization or individual.
What is Media Access Control (MAC)?
MAC refers to the protocol layer that determines how devices on a LAN access the network medium and transmit data without colliding with each other.
What are the two main types of MAC techniques?
- Contention-based (e.g., CSMA/CD, CSMA/CA)
- Controlled access (e.g., Token-passing)
What is CSMA/CD and where is it used?
CSMA/CD (Carrier Sense Multiple Access with Collision Detection) is used in Ethernet networks. Devices listen before transmitting and detect collisions to retransmit data after a random delay.
Why is CSMA/CD not suitable for wireless networks?
Wireless signals have higher propagation delay and may not detect collisions effectively, making CSMA/CD unreliable in wireless environments.
What is CSMA/CA and where is it used?
CSMA/CA (Carrier Sense Multiple Access with Collision Avoidance) is used in wireless networks (e.g., Wi-Fi). Devices wait for the medium to be idle and use a handshake process to avoid collisions.
What is the difference between CSMA/CD and CSMA/CA?
CSMA/CD detects collisions and then retransmits, used in wired Ethernet. CSMA/CA avoids collisions through handshaking, used in wireless networks.
What is token-passing and how does it work?
Token-passing is a MAC method where a special frame (token) circulates the network. Only the device holding the token can transmit data, which prevents collisions.
What are the advantages of token-passing over contention-based MAC?
Token-passing avoids collisions entirely and is better for high-traffic networks or time-sensitive data since access to the network is more predictable.
Which MAC technique is better for time-sensitive traffic like telemetry?
Token-passing is better for time-sensitive traffic because it provides deterministic access, ensuring data is transmitted within a predictable timeframe.
What is the main disadvantage of contention-based MAC?
It can result in frequent collisions when the network is busy, leading to retransmissions, delays, and reduced efficiency.
What role do NICs (Network Interface Cards) play in MAC?
NICs monitor the network for traffic, implement MAC rules (like CSMA/CD or CSMA/CA), and handle the physical sending and receiving of data.
