802.11s MAC Timings
What are MAC timings in 802.11s?
MAC timings define the time intervals and scheduling mechanisms used for transmitting and receiving frames within a mesh network.
Why are MAC timings important in 802.11s?
They ensure orderly and collision-free communication between mesh points, improving reliability and efficiency.
What timing parameters are defined in 802.11s MAC?
Parameters include interframe spaces (SIFS, DIFS), retransmission timers, and mesh peering timeouts.
How does 802.11s handle retransmission timing?
The MAC layer uses backoff timers and retry intervals to manage frame retransmissions after collisions or losses.
What is the role of SIFS in 802.11s MAC?
Short Interframe Space (SIFS) is used to separate transmissions of frames such as ACKs and CTS, ensuring quick response times.
What timing is used for mesh peering management frames?
Mesh peering frames use specific timeout intervals to establish and maintain peering links reliably.
How is collision avoidance timed in 802.11s?
The MAC uses Distributed Coordination Function (DCF) with randomized backoff intervals to minimize collisions.
What is the backoff timer in 802.11s MAC?
It is a randomized timer that delays frame transmission to avoid simultaneous channel access by multiple mesh points.
How does 802.11s MAC coordinate multicast frame timing?
Timing is adjusted to ensure reliable broadcast/multicast forwarding with minimal duplication.
What timers are involved in link maintenance?
Link timers monitor the health of mesh links and trigger reconnection if timeouts occur.
How are timing parameters adapted for different PHY layers?
MAC timings are adjusted based on the physical layer’s data rates and propagation delays.
Does 802.11s use timing for power saving?
Yes, timings help coordinate low-power states and wake intervals for mesh devices.
What is the timing for acknowledgement (ACK) frames?
ACK frames are expected within the SIFS interval after a data frame to confirm successful reception.
How does timing affect mesh routing protocol (HWMP)?
HWMP relies on timing parameters to manage route discovery, path maintenance, and message retries.
What is the impact of timing on throughput in 802.11s?
Proper timing reduces collisions and retransmissions, maximizing effective throughput.
How does MAC timing handle hidden node problems?
Timing protocols like RTS/CTS help avoid collisions caused by hidden nodes by coordinating access timing.
Are MAC timings fixed or adaptive in 802.11s?
Some timings are fixed by standard, while others adapt dynamically based on network conditions.
How are timing conflicts resolved in the mesh network?
Backoff and randomization mechanisms help resolve simultaneous transmission attempts.
What happens if MAC timing parameters are misconfigured?
Misconfiguration can lead to increased collisions, packet loss, and reduced mesh network performance.
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