802.11u Channels ====================== .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **What is 802.11u?** 802.11u is an amendment to the Wi-Fi standard that enables enhanced interworking with external networks like cellular or public hotspots. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **Does 802.11u define new wireless channels?** No, 802.11u uses existing Wi-Fi channels in the 2.4 GHz, 5 GHz, and newer 6 GHz bands. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **How does 802.11u interact with Wi-Fi channels?** It helps devices discover and select networks but depends on the underlying Wi-Fi standard for channel use. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **What frequency bands can 802.11u operate on?** It can operate on any Wi-Fi band supported by the device, including 2.4 GHz, 5 GHz, and 6 GHz bands. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **Can 802.11u help with roaming across channels?** Yes, 802.11u assists fast network discovery and selection, aiding seamless roaming even when switching channels. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **What role do channels play in 802.11u network discovery?** Devices scan available channels to find access points that support 802.11u capabilities. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **Is Dynamic Frequency Selection (DFS) required by 802.11u?** DFS requirements depend on the Wi-Fi band and regulatory rules, not directly on 802.11u. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **How does 802.11u affect channel interference management?** It does not directly manage interference but better network selection helps devices avoid congested channels. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **Can 802.11u work with 20 MHz, 40 MHz, or wider channels?** Yes, it works with whatever channel widths the underlying Wi-Fi standard supports. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **Does 802.11u require specific channels for operation?** No, 802.11u operates over any legal Wi-Fi channels in the device's region. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **How do regulatory domains impact 802.11u channel use?** Local regulations control which channels are available; 802.11u complies with these when selecting networks. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **Can 802.11u improve performance in crowded channels?** Indirectly, by helping devices choose less congested networks on different channels. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **What information do devices get about channels via 802.11u?** Devices learn about network capabilities but not direct control over channels from 802.11u itself. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **Does 802.11u influence transmit power or channel width?** No, these parameters are managed by lower-layer Wi-Fi standards, not 802.11u. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **What tools assist with channel planning for 802.11u networks?** Standard Wi-Fi tools like spectrum analyzers and site surveys are used for channel planning. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **Does 802.11u support 6 GHz Wi-Fi channels?** Yes, it can operate over any Wi-Fi channels supported by the device, including 6 GHz. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **How does channel selection affect 802.11u's interworking features?** Efficient channel use ensures reliable connectivity, which improves the interworking experience. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **Can devices using 802.11u auto-select channels?** Yes, channel auto-selection is a function of the Wi-Fi radio, not 802.11u directly. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow **Does 802.11u affect the physical layer channel characteristics?** No, 802.11u operates at a higher protocol layer focused on network discovery and selection. .. panels:: :container: container pb-4 :column: col-lg-12 p-2 :card: shadow Topics in this section, * :ref:`List of channels ` * :ref:`List of channel widths ` * :ref:`List of Bands ` * :ref:`Reference links ` .. _channels_u_step4: .. tab-set:: .. tab-item:: 2.4 GHz Channels for 802.11u ===================== ======================= ====================== ============== Channel Number (MHz) Center Frequency (MHz) Frequency Range DFS Required ===================== ======================= ====================== ============== 1 2412 2401 – 2423 No 2 2417 2406 – 2428 No 3 2422 2411 – 2433 No 4 2427 2416 – 2438 No 5 2432 2421 – 2443 No 6 2437 2426 – 2448 No 7 2442 2431 – 2453 No 8 2447 2436 – 2458 No 9 2452 2441 – 2463 No 10 2457 2446 – 2468 No 11 2462 2451 – 2473 No 12 2467 2456 – 2478 No (region dependent) 13 2472 2461 – 2483 No (region dependent) 14 2484 2473 – 2495 No (Japan only) ===================== ======================= ====================== ============== .. tab-item:: 5 GHz Channels for 802.11u ===================== ======================= ====================== ============== Channel Number (MHz) Center Frequency (MHz) Frequency Range DFS Required ===================== ======================= ====================== ============== 36 5180 5170 – 5190 No 40 5200 5190 – 5210 No 44 5220 5210 – 5230 No 48 5240 5230 – 5250 No 52 5260 5250 – 5270 Yes 56 5280 5270 – 5290 Yes 60 5300 5290 – 5310 Yes 64 5320 5310 – 5330 Yes 100 5500 5490 – 5510 Yes 104 5520 5510 – 5530 Yes 108 5540 5530 – 5550 Yes 112 5560 5550 – 5570 Yes 116 5580 5570 – 5590 Yes 120 5600 5590 – 5610 Yes 124 5620 5610 – 5630 Yes 128 5640 5630 – 5650 Yes 132 5660 5650 – 5670 Yes 136 5680 5670 – 5690 Yes 140 5700 5690 – 5710 Yes 144 5720 5710 – 5730 Yes 149 5745 5735 – 5755 No 153 5765 5755 – 5775 No 157 5785 5775 – 5795 No 161 5805 5795 – 5815 No 165 5825 5815 – 5835 No ===================== ======================= ====================== ============== .. _channels_u_step5: .. tab-set:: .. tab-item:: List of channel widths * channel widths .. _channels_u_step6: .. tab-set:: .. tab-item:: List of Bands ======================= ====================== ====================== ============================================================ Band Name Frequency Range (GHz) Frequency Range (MHz) Channels ======================= ====================== ====================== ============================================================ 2.4 GHz Band 2.400 – 2.485 2400 – 2485 1 – 14 (region dependent) UNII-1 5.150 – 5.250 5150 – 5250 36, 40, 44, 48 UNII-2 (DFS) 5.250 – 5.350 5250 – 5350 52, 56, 60, 64 UNII-2 Extended (DFS) 5.470 – 5.725 5470 – 5725 100, 104, 108, 112, 116, 120, 124, 128, 132, 136, 140, 144 UNII-3 5.725 – 5.825 5725 – 5825 149, 153, 157, 161, 165 ======================= ====================== ====================== ============================================================ .. _channels_u_step17: .. tab-set:: .. tab-item:: Reference links * Reference links