The medium access control (MAC) sublayer coordinates how network devices use a physical transmission medium and prepares data for transmission. This lesson explains where MAC fits in the data link layer, how it handles frames, and how MAC addresses support delivery on local networks.
In IEEE 802 networks, the MAC sublayer and the logical link control (LLC) sublayer together make up the data link layer, corresponding to Layer 2 of the OSI model. They have related but distinct responsibilities.
All flashcards
What is the MAC sublayer?
The data-link sublayer that manages medium access and link-level functions such as framing and addressing.
How do MAC and LLC responsibilities differ?
MAC manages access to the physical medium; LLC supports logical-link functions and higher-layer protocol identification.
What does a frame check sequence do?
It helps a receiver detect possible transmission errors in a frame, but does not repair them.
What is a multiple access method?
A set of rules that lets several stations share the same physical medium.
What is a MAC address used for?
It identifies a network interface for delivery across a local link.
Quiz questions
In what kind of Ethernet environment was CSMA/CD historically used?Answer: Shared, half-duplex Ethernet where stations contend for the medium.
What is a collision domain?Answer: A network portion where transmissions can collide with one another.
In cellular systems such as LTE, who schedules uplink and downlink access?Answer: The base station controls the air interface and schedules access.
What does it mean that finding an optimal schedule for non-interfering wireless transmissions is NP-hard?Answer: Finding a general exact solution can become computationally impractical as the problem grows.
How can bridges and switches affect Ethernet collision domains?Answer: They can divide an Ethernet network into separate collision domains.