network2025년 12월 11일22 min read

802.11k Overview - AP Assisted Roaming

Explains how the 802.11k standard's Radio Resource Measurement (RRM) feature provides neighbor AP information to enable fast and efficient Wi-Fi roaming

FFrank Advenoh
#802.11#802.11k#802.11v

1. Overview

1.1 IEEE 802.11

This is the international standard that forms the foundation of the wireless local area network (WLAN) we call Wi-Fi today.

  • Definition
    • A collection of wireless communication specifications developed by the 11th working group of the IEEE (Institute of Electrical and Electronics Engineers) 802 committee
  • Purpose
    • Defines the physical layer (PHY) and medium access control (MAC) protocols so that wireless devices can communicate with each other and access the internet without cables
  • Frequency bands
    • Primarily uses the 2.4GHz and 5GHz frequency bands, and the latest standards also leverage the 6GHz band
  • Relationship with Wi-Fi
    • The Wi-Fi Alliance provides interoperability certification for products that comply with the 802.11 standard, and 'Wi-Fi' is the brand name used for products that have received this certification

IEEE 802.11 Standards Timeline

Major 802.11 Standards (Physical) and Features

The table below shows at a glance how Wi-Fi technology has evolved across generations.

Through the changes in speed, frequency bands, and core features, you can easily understand the characteristics and evolutionary direction of each standard.

Wi-Fi GenerationIEEE StandardRelease YearFrequency BandMax Theoretical SpeedKey Features
Wi-Fi 1802.11b19992.4GHz11 MbpsFirst widely adopted standard
Wi-Fi 2802.11a19995GHz54 MbpsIntroduced the 5GHz band
Wi-Fi 3802.11g20032.4GHz54 MbpsImproved speed on 2.4GHz
Wi-Fi 4802.11n20092.4GHz/5GHz600 MbpsMIMO technology, dual-band support
Wi-Fi 5802.11ac20135GHz3.5 GbpsGigabit speeds, 5GHz only
Wi-Fi 6802.11ax20192.4GHz/5GHz~9.6 GbpsOFDMA, high efficiency, improved multi-device performance
Wi-Fi 6E802.11ax20212.4GHz/5GHz/6GHz~9.6 GbpsAdded 6GHz band support
Wi-Fi 7802.11be2024 (planned)2.4GHz/5GHz/6GHzUp to 40 GbpsUltra-fast, wider channel bandwidth

Which Wi-Fi model do you use at home? Using the 802.11ac standard

On a Mac, you can see detailed information by clicking Wi-Fi while holding Opt

Wi-Fi Generations

Along with 802.11r, which we covered last time, we will also look at the 802.11k standard that was published in the same year.

802.11r/k/v

Reference: Roaming in 802.11k/v/r Wi-Fi

2. 802.11k (AP Assisted Roaming)

802.11k is a Radio Resource Measurement standard that helps mobile devices easily find a neighboring AP with a better signal. Thanks to this standard, a device can know the list of nearby APs in advance, so it can roam to the optimal AP faster than with the traditional method. In other words, 802.11k lets a device select an AP more efficiently, improving Wi-Fi performance and stability.

  • Purpose
    • The main purpose is to keep a client from going through an inefficient scanning process to find the optimal AP (access point), thereby reducing the time spent roaming and battery consumption
  • Key Features and Benefits
    • Providing neighbor AP information
      • Normally, when the signal strength weakens, a client scans all available channels to find a new AP. An AP that supports 802.11k provides, upon client request, a Neighbor Report (Neighbor List) containing the list of nearby APs along with information such as their signal strength, channel utilization, and traffic load
    • Fast scanning and efficient roaming
      • Since the client only needs to scan within the provided list rather than scanning all channels, the time it takes to switch to the next AP is greatly reduced
    • Load balancing
      • Prevents clients from concentrating on the AP with the strongest signal and instead directs connections to other APs with lower network load, improving network efficiency
    • Reduced power consumption
      • By reducing the unnecessary full-channel scanning process, it helps save the battery life of mobile devices
  • Disadvantages
    • Network overhead (minor)
      • 802.11k exchanges additional management messages (Neighbor Report requests and responses) between the client and the AP. This overhead is usually negligible, but it can be a consideration in extremely congested environments
    • Compatibility issues (requires both client and AP)
      • 802.11k only works when both the AP and the client device (smartphone, laptop, etc.) support this standard

2.1 How It Works

802.11k

Reference: https://www.researchgate.net/figure/The-Handover-Concept-using-IEEE-80211k-with-neighbor-reports-Figure-10-shows-the-concept_fig9_221922887

802.11k works by sharing information about the surrounding wireless environment between the AP and the client device. The main steps are as follows.

  1. When roaming is triggered
    • When the client's signal strength drops below a certain threshold (when moving away from the connected AP), it determines that the current connection is unstable and proactively prepares to roam
    • The currently connected AP can direct the connected device to another AP if traffic becomes excessively concentrated
  2. Requesting the neighbor AP list (Neighbor Request)
    • When the current signal strength weakens or roaming is needed, the client requests the list of APs adjacent to the current AP
  3. Providing the report
    • In response to the request, the AP provides a Neighbor Report containing detailed information about nearby APs, such as signal quality, available resources, and channel utilization
  4. Selecting the optimal AP
    • Based on this report, the client can quickly decide on the optimal AP to connect to next, without having to search every channel one by one (which is time-consuming and drains the battery)
  5. Fast roaming
    • Because the client knows the optimal AP information in advance, roaming latency is reduced and the connection quality of latency-sensitive applications such as VoIP calls is improved

Reference: Handover Procedure

Handover

Reference: IEEE 802.11 Specification and Handover Procedure

The procedure that takes place when a STA moves to a new AP is as follows.

  1. AP discovery (Scanning phase)

To move to a better AP, the STA must first gather information about nearby APs.

The AP discovery process

  • The STA sends a Probe Request to actively discover whether an AP exists
  • The AP responds with a Probe Response, providing the following information
    • Supported rates, SSID, channel information, security settings
  • Based on the scan results, it builds a candidate AP list (the pre-802.11k method)
    • Active vs Passive Scanning - see the Terminology section
  1. Authentication

This is the phase where the AP determines whether the STA is a user permitted to connect.

  • STAAP: Sends an Authentication Request
  • APSTA: Authentication Response (allow or deny)
  • In an Enterprise environment, additional authentication can be performed by a RADIUS server
  • Only on successful authentication does it proceed to the next phase (Association)
  1. Association - the phase where an actual connection relationship is established with the AP

This is the phase where the STA sets up a connection with the selected AP that allows actual data transmission and reception.

  • STAAP: Sends an Association Request
    • SSID
    • Supported rates
    • Security settings
    • Conveys required features (e.g., whether 11k/11r is supported)
  • APSTA: Association Response
    • When the connection is allowed: the AP issues an AID (Association ID) to the STA
    • Allocates required resources and synchronizes time
  • Internally, the AP
    • Synchronizes the STA with the wireless controller (WLC) or AAA server
    • May notify the previous AP of the STA's move via IAPP, etc.
  1. Connection to the new AP complete
  • The STA is fully connected to the new AP and can start normal communication

Reference: IEEE 802.11 Specification and Handover Procedure

Who creates the Neighbor List?

2.1.1 WLC - Centralized Network Management System

In most enterprise or large-scale Wi-Fi environments, APs are managed by a central Wireless LAN Controller (WLC) system.

WLC

Reference: https://404notonc.tistory.com/153

When you enable the 802.11k feature in the WLC (Wireless LAN Controller) settings, the AP and the WLC cooperate to efficiently generate the Neighbor Report (Neighbor List).

This process operates as a hybrid approach that combines periodic information exchange with dynamic generation upon client request, and the specific implementation may differ slightly among network equipment manufacturers (Cisco, Aruba, Juniper, etc.)

1. Periodic information exchange (Neighbor caching)

For network efficiency, instead of generating a completely new list immediately each time, APs collect the necessary information in advance.

  • AP measurement and reporting
    • When 802.11k is enabled, each individual AP periodically scans the surrounding channels and measures information such as the signal strength, channel information, and BSSID of neighboring APs
  • Sending information to the WLC
    • The AP reports these measurement results to the WLC
  • The WLC builds a Neighbor Database
    • The WLC aggregates the information received from all APs connected to the network to build a centralized neighbor AP database (Neighbor Database) or cache

2. Response upon client request (dynamic generation and lookup)

When an actual client needs to roam, the WLC responds quickly using the cached information.

  • The client's Neighbor Request
    • For roaming, the client sends an 802.11k neighbor request message (Neighbor Request) to the currently connected AP
  • The WLC generates a response
    • The AP that received the request forwards it to the WLC
    • The WLC looks up the previously built database (cache) and dynamically generates an optimized neighbor AP list that takes into account the client's location and current state
  • Delivery to the client
    • The WLC delivers this list (Neighbor Report) back to the client through the AP

References

Information included in the Neighbor Report

Information ItemDescription
BSSIDThe unique MAC address of the neighboring AP
Channel InformationThe wireless channel currently used by the neighboring AP
Received Signal Strength Indicator (RSSI)The signal strength of the neighboring AP as measured by the client device
Operating Class and PHY TypeOperational details such as the AP's operating frequency band (e.g., 2.4GHz, 5GHz, 6GHz) and supported physical layer (PHY) types (e.g., 802.11n, 802.11ac, 802.11ax)
Capability InformationContains information elements (IEs) indicating the features supported by the AP (e.g., security methods, roaming support protocols, etc.)

2.3 Performance Comparison

Not found

3. How to Configure and Use 802.11k

  • It can only be used if both the AP and the Client support 802.11k
    • Even if the AP supports it, it must be enabled in the WLC administrator web UI
    • If the Client Wi-Fi device supports 802.11k, it detects that this feature is enabled on the AP and automatically uses it without additional activation

3.1 Does the Client Wi-Fi device also support 802.11k?

> sudo lspci -k | grep -A3 -i network
[sudo] password for around:
02:00.0 Ethernet controller: Intel Corporation I211 Gigabit Network Connection (rev 03)
	Subsystem: Intel Corporation I211 Gigabit Network Connection
	Kernel driver in use: igb
	Kernel modules: igb
03:00.0 Ethernet controller: Intel Corporation I211 Gigabit Network Connection (rev 03)
	Subsystem: Intel Corporation I211 Gigabit Network Connection
	Kernel driver in use: igb
	Kernel modules: igb
04:00.0 Network controller: Intel Corporation Wi-Fi 6 AX200 (rev 1a)
	Subsystem: Intel Corporation Wi-Fi 6 AX200
	Kernel driver in use: iwlwifi
	Kernel modules: iwlwifi

IEEE WLAN

  • How to check via command
# The iw command is used on linux to configure wireless devices and display information
# phy capability information
> iw phy | grep RRM
     * [ RRM ]: RRM
# RRM stands for Radio Resource Management, meaning it supports the feature set that includes the 802.11k standard

3.2 Does the AP support 802.11k?

  • The AP must support it, and it must be enabled in the administrator admin UI
    • Assisted Roaming Prediction Optimization: a feature for clients that do not support 802.11k

WLC Settings

Capture

4. FAQ

4.1 Is it okay to configure and use multiple Wi-Fi roaming standards at the same time?

  • Most real-world enterprise/industrial Wi-Fi setups use them together, since each has a different role and they complement each other

4.2 What kind of network is used at drone events?

  • At a drone show event, Wi-Fi is used as the primary network, but due to stability and bandwidth concerns, it is combined with a mesh network, dedicated RF (radio frequency), or a multi-radio combination
    • Wi-Fi based (primary):
      • High-performance 5GHz APs (e.g., Ubiquiti XG AP, supporting 100-150 units) transmit telemetry/commands between the ground station (GCS - Ground Control System) and the drones
      • 2.4GHz is used only in a limited way due to heavy interference
    • Mesh network
      • P2P communication between drones reduces dependence on the central ground station, and strengthens collision avoidance/synchronization
      • Local decision-making via edge computing
    • Dedicated RF + multi-radio
      • Simultaneous use of dedicated 900MHz/2.4GHz wireless modules in addition to Wi-Fi
      • The entire show file is uploaded in advance, enabling offline flight (minimizing real-time control)
    • Backup/redundancy: GNSS/RTK positioning + 5G (the latest trend) for 0ms-latency synchronization

4.3 PSK, PMK, PTK - these terms are confusing; how are they actually used in the authentication and roaming authentication flows?

  • A diagram that shows at a glance which keys are created and how they are passed in the robot (client) ↔ AP ↔ authentication server (RADIUS) process, and which keys are reused during roaming

    1. Common structure of WPA2-PSK and WPA2-Enterprise (EAP)
    ┌────────────────────────────┐
    │        Robot (Client)└────────────────────────────┘
                │ ① PSK input or EAP authentication
        PSK (password)  →  PMK generation
        EAP-TLS/EAP-PEAP → PMK generation
    ┌────────────────────────────┐
    │   PMK (Pairwise Master Key)│  ← the core key reused during roaming
    └────────────────────────────┘
                │ ② 4-Way Handshake with AP
      PTK (Pairwise Transient Key) generation
      GTK (Group Temporal Key) reception
    ─────────── Wi-Fi connection complete ───────────
                │ ③ Robot moves → needs to switch to another AP
    
    1. 802.11r (FT) Fast Roaming structure
    • When you configure an 802.11r environment, the robot does not need to regenerate the PMK when roaming between APs → very fast switching
                       (Controller/CAPWAP or direct sharing between APs)
           ┌──────────────────────────────────────────┐
           │          PMK-R0 (root key)       └──────────────────────────────────────────┘
                 ┌─────────────┴─────────────┐
                 ▼                           ▼
    ┌─────────────────────┐       ┌─────────────────────┐
    │ AP1 (R0KH / R1KH)   │       │ AP2 (R0KH / R1KH)└─────────────────────┘       └─────────────────────┘
                 │                           │
                 │  Robot moves               │
                 │───────────────▶───────────│
                 ▼                           ▼
    
     Robot connected to AP1                   Robot roams to AP2
     ───────────────────                        ───────────────────
    
    1) Generate PMK-R1 for AP1 from PMK-R0   1) Generate PMK-R1 for AP2 from PMK-R0
    2) Generate PTK from PMK-R1              2) Generate PTK from PMK-R1 (new)
    3) Connection maintained                3) Reconnect very quickly (in ms)
    
    1. Integrated diagram showing the entire flow at once

    The figure below shows the entire process at a glance, from PSK/EAP → PMK → PTK → FT roaming

                                      ┌────────────────────────────┐
                                      │   Authentication Server(EAP)(RADIUS / 802.1X)                                  └────────────────────────────┘
                                       ▲             │
                                       │EAP message  │ PMK delivery (Enterprise)
                                       │             ▼
          ┌────────────────────────────┐       ┌────────────────────────────┐
          │        Robot (Client)      │       │     AP1 (R0KH / R1KH)      └────────────────────────────┘       └────────────────────────────┘
                │                                     │
                │1) PSK or EAP authentication         │
                ▼                                     │
          PMK generation  ◀────────────────────────────┘
                │2) 4-Way Handshake (AP1)
            PTK generation
    ────────── Connection successful ──────────
                │3) Robot moves → AP2 has a better signal
          ┌────────────────────────────┐
          │     AP2 (R0KH / R1KH)      └────────────────────────────┘
                │4) 802.11r FT roaming request
    (reuse PMK-R1)
          New PTK generation (fast reconnection)
    ────────── Roaming complete (in ms) ──────────
    

4.4 How can wireless network packets be captured?

5. Terminology

5.1 What is Wi-Fi roaming?

  • Wi-Fi roaming is a technology where a mobile device automatically switches to a stronger AP, and enabling 802.11r/k/v can greatly improve the switching speed and stability
  • 802.11r (Fast BSS Transition: fast AP switching)
    • FT is a feature where a Wi-Fi client reconnects quickly when roaming between APs by optimizing the handshake process instead of repeating the existing authentication procedure
    • Fast BSS Transition skips the authentication process, reducing handover time to within 50ms. Fast switching based on k/v information
  • 802.11k (Radio Resource Measurement)
    • By providing nearby AP information (neighbor report), the robot identifies optimal AP candidates without scanning. Automatically triggers 802.11v activation
  • 802.11v (Wireless Network Management)
    • Through BSS transition management, the network instructs the robot to "move to a better AP". Optimizes load balancing and roaming triggers.
Feature802.11r (Fast BSS Transition)802.11k (Radio Resource Measurement)802.11v (Wireless Network Management)
Main purposeFast roaming (skip authentication)Provide nearby AP information (scan optimization)BSS transition management and load balancing
Operating phaseAt handover executionNeighbor report collection before/after connectionNetwork optimization suggestions while connection is maintained
Core feature- OKC (Opportunistic Key Caching)
  • Reduces authentication time by 50ms | - Neighbor Report
  • Channel/signal strength information
  • 90% ↓ in scan time | - BSS Transition Management
  • "Move to a better AP" request
  • Load balancing | | Robot effect | Ping-pong handover ↓ | Unnecessary scans ↓, battery saving | Escape overloaded AP, maintain stable connection | | Requirement | Same Mobility Domain (MDID) | Neighbor table configuration between APs | Client consent required (some can refuse) | | Compatibility | Supported by most iOS/Android | Broadly supported (including legacy) | Mainly newer devices, some limitations |

5.2 Wireless Signal Terms

  • RSSI (Received Signal Strength Indicator)

    • Received signal strength
    • The closer to 0, the stronger; below 90dBm is a very weak signal
    • Used to determine how far the robot is from the AP
  • SNR (Signal-to-Noise Ratio)

    • The ratio of signal to noise

    • The higher the SNR, the more stable (e.g., 30dB or higher is good)

    • Example:

      • RSSI = -60 dBm

      • Noise = -90 dBm

        SNR = 30 dB (good)

    • RSSI is the signal itself, while SNR is the quality of the signal (relative to noise)

5.3 Wi-Fi Encryption/Key Terms

  • PSK (Pre-Shared Key)
    • A shared password (= the Wi-Fi password we enter)
    • Used in WPA/WPA2-Personal mode
  • PMK (Pairwise Master Key)
    • The higher-level key generated during the PSK or EAP authentication process
      • The core key actually used for Wi-Fi communication encryption is the PMK
      • Derived from the PSK (password) (using HMAC-SHA1)
    • The core of roaming: the PMK can be shared between APs
      • The master key generated when a client connects to an AP in WPA/WPA2/later security modes
    • Password (PSK) → generate encryption master key (PMK) → perform actual communication encryption
  • PMK caching (or PMKID)
    • PMK Caching or PMKID caching is a method where, after a client first authenticates/connects to an AP, the generated PMK or PMKID is remembered or stored in the network, so that the full authentication procedure does not need to be repeated when roaming to another AP
  • PTK (Pairwise Transient Key)
    • The actual data encryption key derived from the PMK

5.4 Wi-Fi Authentication Terms

  • EAP (Extensible Authentication Protocol) - a framework of authentication (login) methods

    • A collection of various methods for performing 'user authentication' in WPA

      • That is, it is the sub-protocol that determines how authentication is handled in WPA
    • An advanced authentication protocol used in enterprise/school Wi-Fi

    • For example, the following methods are EAP-based:

      • EAP-TLS (the strongest, based on public-key certificates)

      • PEAP (password-based + authentication inside a TLS tunnel)

      • EAP-TTLS (supports multiple authentication methods inside a TLS tunnel)

        ItemEAP-TLSPEAPEAP-TTLS
        Authentication methodClient + server certificateTLS tunnel + passwordTLS tunnel + multiple auth methods
        Security⭐⭐⭐⭐⭐ Highest⭐⭐⭐⭐⭐⭐⭐
        Certificate requiredClient + serverServer onlyServer only
        Management difficultyDifficultEasyMedium
        Suitability for robotsBest if certificate management is feasibleEasiestFlexible, suitable for robots/IoT
        Windows supportVery goodVery goodLimited
    • The authentication method used in WPA2-Enterprise environments

5.5 Security Protocols

  • WPA (Wi-Fi Protected Access: the overall Wi-Fi encryption standard / security specification)

    • WPA is the overall security specification that defines how a Wi-Fi network is protected; it is the entire framework of Wi-Fi security

    • That is, WPA defines things like:

      • Which encryption algorithm to use? (TKIP? AES?)
      • How to authenticate? (password? authentication server?)
      • How to manage keys? (4-way handshake)
      • Roaming support? (802.11r)
    • WPA has 2 authentication modes

      WPA Authentication MethodDescriptionUse Case
      PSK (Pre-Shared Key)The "Wi-Fi password" authentication method used at homeWPA2-PSK
      EAP / 802.1XAuthentication protocol via a corporate authentication server (RADIUS)WPA2-Enterprise
  • Types:

    • WPATKIP based (the old method)
    • WPA2AES based (the current standard)
      • WPA2-PSK (the password-based Wi-Fi used at home)
      • WPA2-Enterprise (corporate Wi-Fi based on 802.1X/EAP)
    • WPA3 → an enhanced, latest standard (uses SAE)
      • WPA3-SAE
      • WPA3-Enterprise
  • WPA is the name of the standard that defines "how to apply security in Wi-Fi", and PSK/PMK are the concepts of the encryption keys actually used within it.

5.6 BSSID (Basic Service Set Identifier)

  • The MAC address of the AP
  • The SSID is the Wi-Fi name, while the BSSID is the AP device ID

5.7 SSID (Service Set Identifier)

  • The name by which a user identifies and connects to their Wi-Fi network
  • What you see when you view the Wi-Fi list on a device is the SSID

5.8 Wi-Fi Band

  • Refers to a specific frequency range allocated for wireless communication; the communication speed, range, and level of interference vary depending on this frequency band. The bands currently in common use are 2.4GHz, 5GHz, and the latest technology, 6GHz

5.9 Channel

  • A channel refers to the specific frequency band that an AP uses for communication (e.g., channel 1, 6, 11 or 36, 149, etc.)
  • One AP usually uses one channel, or two channels (one in the 2.4GHz band, one in the 5GHz band)

5.10 Scanning

  • Scanning refers to the process by which a device finds nearby Wi-Fi APs and collects information needed to connect. This process is generally done in two ways
    • Passive Scanning: a method where the client quietly listens for the Beacon frames that an AP periodically broadcasts to obtain information. Since it has to check all channels, it can take a long time
    • Active Scanning: a method where the client sends a Probe Request frame on a specific channel and the AP sends a Probe Response frame in return to obtain information. It is faster than passive scanning, but time can still be consumed in the process of scanning across multiple channels

5.11 WLC (Wireless LAN Controller)

  • The operating principle of the WLC (Wireless LAN Controller) is centered on centralized management: it integrates control of multiple APs (access points) from a single controller, configures SSID, security policies, channels, etc. in bulk, and automates load balancing, RF optimization, client roaming, and fault management to efficiently operate large-scale wireless networks

    Main operating principles

    1. Centralized control
      • The administrator only needs to configure a single WLC rather than individual APs, and it distributes the same SSID, security (WPA3, 802.1X, etc.), and channel settings to all APs
    2. Automatic AP discovery and configuration: when an AP connects to the WLC, it is automatically assigned an IP and is configured by receiving configuration information from the WLC
    3. Separation of control and data
      • Control traffic: the WLC manages settings, state synchronization, authentication information, etc. between the AP and the WLC (e.g., the CAPWAP protocol).
      • Data traffic: the user's actual data (web browsing, file transfer, etc.) may be forwarded directly from the AP to the wired network (switch/router) without passing through the WLC, which is efficient (depends on the controller's location)
    4. RF and performance management
      • Channel optimization: automatically adjusts channels to avoid interference between adjacent APs
      • Load balancing: distributes load so that clients do not crowd onto a particular AP
      • Automatic failure recovery: if a problem occurs on a particular AP, nearby APs automatically adjust to cover that area
    5. Enhanced security: applies strong security protocols centrally and uniformly applies intrusion detection and access control policies to all APs to strengthen network security

    The WLC communicates with the APs to exchange control information, and client devices (laptops, smartphones, etc.) connect through the APs to the wired network connected to the WLC

6. References

7. Appendix

7.1 Commands

7.1.1 Printing the Wi-Fi Device Connection Status

This is a status query command used to check which AP/SSID the wlp4s0 interface is currently attached to and in what state.

  • wpa_cli
    • A CLI frontend tool for wpa_supplicant
    • Lets you check the current authentication state, connected SSID, BSSID, pre-IP-assignment state, etc., and perform tasks such as reconnecting and scanning
sudo wpa_cli -i wlp4s0 status
bssid=##:##:##:##:##:##
freq=5180
ssid=######
id=0
mode=station
wifi_generation=6
pairwise_cipher=CCMP
group_cipher=CCMP
key_mgmt=WPA2-PSK
wpa_state=COMPLETED
ip_address=##.##.##.##
p2p_device_address=##:##:##:##:##:##
address=##:##:##:##:##:##
uuid=6f10a4a1-5f5e-5adb-8dd5-cc6934d05dae
ieee80211ac=1