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| docs:guide-user:network:wifi:roaming [2024/11/14 13:44] – [Verifying client 802.11r support] cleanup quoting, grammar. timsmall | docs:guide-user:network:wifi:roaming [2024/11/15 13:13] – [802.11k and 802.11v] typo timsmall |
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| Over time, a number of optional features have been added to the WiFi standards to try to increase roaming performance within an ESS. These include: | Over time, a number of optional features have been added to the WiFi standards to try to increase roaming performance within an ESS. These include: |
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| * 802.11r ("Fast Transition") reduces the time taken for a client to establish a secure connection when roaming to a different BSSID. | * **802.11r** ("Fast Transition") reduces the time taken for a client to establish a secure connection when roaming to a different BSSID. |
| * 802.11k ("Radio Resource Measurement") allows a single BSSID provide wifi clients with a list of other BSSIDs and frequencies which are included in the ESS. This reduces the time that each client needs to spend looking for an alternative "better" SSID because it no longer needs to scan all frequencies. | * **802.11k** ("Radio Resource Measurement") allows a single BSSID provide wifi clients with a list of other BSSIDs and frequencies which are included in the ESS. This reduces the time that each client needs to spend looking for an alternative "better" SSID because it no longer needs to scan all frequencies. |
| * 802.11v ("Wireless Network Management") this standard includes "Network assisted Roaming" whereby the BSSID can recommend alternative BSSIDs that the client could roam to. | * **802.11v** ("Wireless Network Management") this standard includes "Network assisted Roaming" whereby the BSSID can recommend alternative BSSIDs that the client could roam to. |
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| ====== 802.11r Fast Transition ====== | ===== 802.11r Fast Transition ===== |
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| 802.11r is sometimes used in conjunction with other related standards such as 802.11k and 802.11v. | 802.11r is sometimes used in conjunction with other related standards such as 802.11k and 802.11v. |
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| ===== Configuring ===== | ==== Configuring ==== |
| The full set of 802.11r related options which OpenWrt supports can be found [[:docs:guide-user:network:wifi:basic#fast_bss_transition_options_80211r|here in the documentation]]. | The full set of 802.11r related options which OpenWrt supports can be found [[:docs:guide-user:network:wifi:basic#fast_bss_transition_options_80211r|here in the documentation]]. |
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| * [[docs:guide-user:network:wifi:dawn|Setting up DAWN and band-steering in OpenWrt]] (older project, may not be relevant) | * [[docs:guide-user:network:wifi:dawn|Setting up DAWN and band-steering in OpenWrt]] (older project, may not be relevant) |
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| ===== Wifi clients with no or limited support for 802.11r ===== | ==== Wifi clients with no or limited support for 802.11r ==== |
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| Clients without 802.11r support should connect to networks with 802.11r enabled, however **some buggy clients are known to refuse to associate** with networks which have 802.11r enabled, or have other problematic behaviour. A workaround for this is to create a separate "legacy" SSID which has 802.11r disabled, for those devices alone to connect to. In some cases upgrading the client firmware, drivers, or OS may fix issues. | Clients without 802.11r support should connect to networks with 802.11r enabled, however **some buggy clients are known to refuse to associate** with networks which have 802.11r enabled, or have other problematic behaviour. A workaround for this is to create a separate "legacy" SSID which has 802.11r disabled, for those devices alone to connect to. In some cases upgrading the client firmware, drivers, or OS may fix issues. |
| * Some Intel Windows wifi6 client cards with driver versions 23.60.* would fail to re-associate to OpenWrt 23.x access points when 802.11r with PSK was enabled. Upgrading to Intel driver version 23.90.* fixed the problem. | * Some Intel Windows wifi6 client cards with driver versions 23.60.* would fail to re-associate to OpenWrt 23.x access points when 802.11r with PSK was enabled. Upgrading to Intel driver version 23.90.* fixed the problem. |
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| ===== Verifying client 802.11r support ===== | ==== Verifying client 802.11r support ==== |
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| To check if 802.11r is working properly, set log_level to 1 (cf. [[:docs:guide-user:network:wifi:basic#common_options1|Common Options]]) and look for message "//FT authentication already completed - do not start 4-way handshake//" in your system log after roaming. | To check if 802.11r is working properly, set log_level to 1 (cf. [[:docs:guide-user:network:wifi:basic#common_options1|Common Options]]) and look for message "//FT authentication already completed - do not start 4-way handshake//" in your system log after roaming. |
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| When 802.11r is in use, this can be found in each Association Request frame, under ''IEEE 802.11 Wireless Management'' -> ''Tagged parameters'' -> ''RSN Information'' -> ''Auth Key Management (AKM) List''. | When 802.11r is in use, this can be found in each Association Request frame, under ''IEEE 802.11 Wireless Management'' -> ''Tagged parameters'' -> ''RSN Information'' -> ''Auth Key Management (AKM) List''. |
| ====== 802.11k and 802.11v ====== | ===== 802.11k and 802.11v ===== |
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| The "hostap" management software forms a key part of OpenWrt in that it manages advertising WiFi networks and authenticating WiFi clients. hostapd includes support for 802.11k and 802.11v, but relies on external software to make roaming recommendations and provide it with lists of alternative bssids etc. OpenWrt includes the following software packages which can perform these functions: | The "hostap" management software forms a key part of OpenWrt in that it manages advertising WiFi networks and authenticating WiFi clients. hostapd includes support for 802.11k and 802.11v, but relies on external software to make roaming recommendations and provide it with lists of alternative BSSIDs etc. OpenWrt packages software which can perform these functions and are intended to manage both 802.11k and 802.11v. Only one should be active at a time: |
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| * [[:docs:guide-user:network:wifi:dawn]] | * [[:docs:guide-user:network:wifi:dawn]] |
| * [[:docs:guide-user:network:wifi:usteer]] | * [[:docs:guide-user:network:wifi:usteer]] |
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| Each package expects to have sole responsibility for 802.11k and 802.11v operation, and so only one should be installed. | Alternative packages which only implement 802.11k include: |
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| | * [[https://github.com/simonyiszk/openwrt-rrm-nr-distributor|rmm-nr-distributor]] |
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| | ===== Additional Resources ===== |
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| | * [[https://youtu.be/4Ua2lI6HBhE?&t=24|A talk given at Wireless Lan Professionals Conference 2019 entitled "Effects of 802.11k/r/v"]] |