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Wey-Yi Guy authored
When 802.11g was introduced, we had RTS/CTS and CTS-to-Self protection mechanisms. In an HT Beacon, HT stations use the "Operating Mode" field in the HT Information Element to determine whether or not to use protection. The Operating Mode field has 4 possible settings: 0-3: Mode 0: If all stations in the BSS are 20/40 MHz HT capable, or if the BSS is 20/40 MHz capable, or if all stations in the BSS are 20 MHz HT stations in a 20 MHz BSS Mode 1: used if there are non-HT stations or APs using the primary or secondary channels Mode 2: if only HT stations are associated in the BSS and at least one 20 MHz HT station is associated. Mode 3: used if one or more non-HT stations are associated in the BSS. When in operating modes 1 or 3, and the Use_Protection field is 1 in the Beacon's ERP IE, all HT transmissions must be protected using RTS/CTS or CTS-to-Self. By default, CTS-to-self is the preferred protection mechanism for less overhead and higher throughput; but using the full RTS/CTS will better protect the inner exchange from interference, especially in highly-congested environment. For 6000 series WIFI NIC, RTS/CTS protection mechanism is the recommended choice for HT traffic based on the HW design. Signed-off-by:
Wey-Yi Guy <wey-yi.w.guy@intel.com> Signed-off-by:
Reinette Chatre <reinette.chatre@intel.com> Cc: stable@kernel.org Signed-off-by:
John W. Linville <linville@tuxdriver.com>
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