802.11d Packet Formats
What is the basic packet format in IEEE 802.11d?
IEEE 802.11d uses the standard 802.11 MAC frame structure with additional information elements for regulatory domain info.
What types of frames are defined in 802.11d?
Management, control, and data frames, as per the 802.11 standard, with added regulatory info in management frames.
How does 802.11d indicate regulatory domain info in packets?
Through the Regulatory Information Element (Regulatory IE) in management frames like Beacon and Probe Response frames.
What is the purpose of the Regulatory Information Element?
It informs devices about allowed channels, power limits, and other region-specific regulations.
In which management frames is the Regulatory IE carried?
Typically in Beacon frames, Probe Response frames, and sometimes Association Response frames.
Does 802.11d modify the MAC header?
No, the MAC header remains standard; 802.11d adds regulatory info as an Information Element inside management frames.
What fields are included in the Regulatory Information Element?
Country String, Regulatory Class, Channel Number, Max Transmit Power, etc.
How long is the Regulatory IE?
It varies but generally between 3 to 8 bytes depending on the number of regulatory classes included.
Are data frames affected by 802.11d?
No, 802.11d focuses on regulatory info in management frames, so data frame format remains unchanged.
Can 802.11d devices ignore Regulatory IE if unsupported?
Devices not supporting 802.11d may ignore the Regulatory IE but might face regulatory compliance issues.
Does 802.11d add new control frames?
No, control frames remain the same as in original 802.11 standards.
How does the packet format help with global roaming?
The Regulatory IE allows devices to adjust their channel and power settings based on the region they are operating in.
Is the packet format backward compatible with older 802.11 devices?
Yes, because regulatory info is included as optional Information Elements, older devices simply ignore them.
What is the format of a typical management frame in 802.11d?
Standard 802.11 management frame format + optional Regulatory IE appended.
How is the Country String formatted in Regulatory IE?
It is a 3-byte ASCII string indicating country code, e.g., “US “, “JP “, or “EU “.
Do 802.11d packets carry information about allowed frequency bands?
Yes, Regulatory IE specifies allowed channels and frequency ranges.
Are there changes in security fields in 802.11d packet formats?
No, 802.11d does not modify security-related fields.
How do stations process the Regulatory IE in received packets?
Stations parse the Regulatory IE to update their channel and power settings as per local regulations.
Is the packet format for 802.11d mandatory for all 802.11 devices?
Devices operating in multiple regulatory domains are recommended to implement it; others may not be required.
Topics in this section,
Reference links