802.11n Packet Formats
What is the basic structure of an 802.11n MAC frame?
It consists of a MAC header, frame body (payload), and a Frame Check Sequence (FCS) for error detection.
What fields are included in the MAC header of 802.11n?
Frame Control, Duration/ID, Address fields (up to 4), Sequence Control, QoS Control, and HT Control.
How does 802.11n support Quality of Service (QoS) in packet formats?
By including the QoS Control field to prioritize traffic and support enhanced traffic categories.
What is the role of the HT Control field in 802.11n frames?
It carries additional control information related to high throughput features like aggregation and block acknowledgment.
How many address fields can an 802.11n MAC frame have?
Up to four address fields to support various network topologies such as infrastructure and mesh networks.
What types of frames are defined in 802.11n?
Management, Control, and Data frames, each with specific formats and purposes.
How does 802.11n handle frame aggregation?
It uses A-MPDU and A-MSDU aggregation formats to combine multiple frames for efficient transmission.
What is the difference between A-MPDU and A-MSDU?
A-MPDU aggregates multiple MAC Protocol Data Units with individual headers; A-MSDU aggregates multiple MSDUs within a single MAC frame.
How does frame fragmentation work in 802.11n?
Large frames can be split into smaller fragments, each with its own header and FCS, to improve reliability.
What is the purpose of the Frame Check Sequence (FCS)?
It is a CRC field used to detect errors in the transmitted frame.
Does 802.11n packet format support security features?
Yes, it supports encryption through the MAC header with fields for encryption keys and security protocols.
What are the main differences in packet format between 802.11n and earlier standards?
Addition of HT Control field, support for aggregation, and enhanced QoS features.
How is the duration/ID field used in 802.11n packets?
It indicates the time the medium will be reserved or carries association information.
What is the role of Sequence Control field?
It helps in ordering frames and detecting duplicates.
How do 802.11n packet formats handle multicast and broadcast frames?
Special flags and addressing are used to identify and manage these frames efficiently.
Can 802.11n packets carry vendor-specific information?
Yes, through Information Elements in management frames, vendor-specific data can be included.
How are control frames formatted in 802.11n?
They have simpler formats focused on acknowledgment, request-to-send, and clear-to-send functions.
What is the maximum payload size supported in 802.11n packets?
With aggregation, payloads can be several megabytes, significantly larger than in earlier standards.
How does packet format influence throughput in 802.11n?
Efficient frame aggregation and header compression reduce overhead and increase throughput.
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