Creator, David Coleman, gives a quick preview of the weblog in his personal phrases within the audio clip beneath.
That is the fifth in a collection of continuous blogs about Wi-Fi 6E and the brand new spectrum bonanza within the 6 GHz frequency band. And that is the second of two blogs the place I talk about how the normal strategies of AP discovery not apply for Wi-Fi 6E purchasers.
Wi-Fi purchasers have historically used an lively hunt-and-seek methodology to scan for entry factors (APs). Purchasers ship out probe request frames throughout all channels to find APs. Nonetheless, as I mentioned in my previous blog, we are actually getting into the age of Wi-Fi 6E, and lively probing is discouraged within the 6 GHz frequency band. The standard lively scanning methodology is not environment friendly for preliminary AP discovery and even worse for roaming between APs. The underside line is that consumer probing takes an excessive amount of time as a result of there are such a lot of channels within the 6 GHz band. In my final weblog, I lined the three in-band discovery mechanisms for six GHz. Nonetheless, a brand new out-of-band AP discovery mechanism has been designated because the major methodology for Wi-Fi 6E purchasers to seek out Wi-Fi 6E APs.
The chipsets utilized in Wi-Fi 6E consumer radios will even have 2.4 and 5 GHz capabilities, that means they will additionally scan and connect with APs utilizing the legacy frequency bands. A tri-band AP can inform a Wi-Fi 6E consumer actively probing the two.4 GHz or 5 GHz bands in regards to the present 6 GHz radio co-located within the AP. Due to this fact, a clearly outlined out-of-band discovery methodology to tell Wi-Fi 6E purchasers about 6 GHz APs gives a guiding mild… the decreased neighbor report (RNR).
802.11v first outlined the attainable use of a decreased neighbor report (RNR) info ingredient that can be utilized to incorporate details about a neighbor AP. For Wi-Fi 6E, the “neighbor AP” is definitely the 6 GHz radio housed in the identical AP together with the two.4 GHz and 5 GHz radios. Wi-Fi 6E purchasers will study in regards to the out there 6 GHz radio from the RNR info in both beacon or probe response frames despatched by the AP’s 2.4 and 5 GHz radios.
Within the instance proven in Determine 1, a Wi-Fi 6E consumer sends directed probe requests throughout the 5 GHz band for an SSID known as blue. Three APs reply with probe responses that carry fundamental service set (BSS) parameters for the blue SSID for the 5 GHz channels of 36, 40, and 44. Nonetheless, inside every probe response can be RNR details about the 6 GHz radios transmitting on channels 53, 85, and 117. The SSID is perhaps the identical throughout bands or totally different in every frequency. The consumer can then determine whether or not to connect with the 5 GHz radio of the AP or, extra probably, the out there 6 GHz radio. Clearly, the purpose is to get rid of probing time on the 6 GHz band. The consumer machine is knowledgeable of accessible 6 GHz BSSs with out ever scanning the 6 GHz band. By the way in which, the instance in Determine 1 makes use of directed probe requests with a identified SSID; nevertheless, the identical RNR info is delivered to purchasers that ship probe requests with a null SSID area, typically known as a Wildcard SSID.
Determine 1: Out-of-band discovery
Additionally, the identical out-of-band discovery methodology is used when the Wi-Fi 6E consumer probes the two.4 GHz band. The probe responses from the two.4 GHz radios within the APs will reply about 2.4 GHz channel availability and RNR details about the 6 GHz radios co-located in the identical AP. Determine 2 reveals an RNR info ingredient from a 5 GHz probe response body. Notice that it signifies a 6 GHz major channel of 37 that’s co-located in the identical AP. The working class is a sign of the 6 GHz channel measurement. An working class of 134 signifies a 160 MHz channel. Likewise, 133 denotes an 80 MHz channel, 132 signifies a 40 MHz channel, and 131 signifies a channel measurement of 20 MHz.
Determine 2 – Decreased neighbor report
The Brief SSID parameter in a decreased neighbor report (RNR) is successfully a hash of the 6 GHz SSID. The RNR info ingredient can even point out whether or not or not the 6 GHz SSID is similar because the 5 GHz SSID. If the reported 6 GHz radio and the reporting 2.4/5 GHz radios are configured with the identical SSID, both the brief SSID area is about to the brief SSID of 6 GHz AP or identical SSID subfield is about to 1. If the Identical SSID area is about to 0, then the brief SSID is strictly the 6 GHz SSID. In an earlier blog, I wrote that I anticipate there to be totally different SSIDs with totally different ranges of safety for use on the varied bands. WPA3 will certainly be utilized in 6 GHz. But, regardless of the assist for WPA3 transition modes within the legacy bands, WPA2 will probably stay prevalent within the 2.4 GHz and 5 GHz bands for a really very long time.
The working class info talked about earlier is necessary as a result of for the primary time, the usage of 80 MHz channels will probably be a actuality for enterprise deployments. In the US, 14 channels can be found for an 80 MHz channel reuse plan in 6 GHz. The FCC has outlined new transmit energy guidelines that truly favor the usage of massive 80 MHz channels. In consequence, 80 MHz channel reuse patterns within the enterprise may change into widespread in nations with 1,200 MHz of 6 GHz frequency house out there. As proven in Determine 3, if the RNR info present in a 5 GHz probe response indicated a major channel of 69 and an working class of 133, the 6 GHz radio housed in the identical AP could be transmitting on the 80 MHz channel of 71.
Determine 3: Working class: 133 | Main channel: 69 | 80 MHz channel: 71
So, what if a consumer connects to a 6 GHz AP utilizing the first channel 53 and desires to roam to a different 6 GHz AP? Imagine it or not, the most probably consumer lively scanning methodology will as soon as once more be for the Wi-Fi 6E consumer to probe the two.4 and/or 5 GHz channels to get RNR details about attainable close by 6 GHz APs to which the consumer would possibly roam. Within the instance proven in Determine 4, a Wi-Fi 6E consumer related to the 6 GHz channel 53 of AP-1, can nonetheless use 5 GHz probe requests with RNR info to find the 6 GHz radio housed in AP-2 utilizing the first channel of 85. After studying about this info and constructing a 6 GHz roaming desk, the Wi-Fi 6E consumer is free to roam based mostly on no matter pre-determined roaming thresholds the consumer would possibly use. As soon as once more, consumer probing is inefficient in 6 GHz and takes an excessive amount of time; there are too many 6 GHz channels to scan.
Determine 4 – Roaming with out-of-band discovery
On a facet word, I believe that after Wi-Fi 6E purchasers connect with a 6 GHz AP radio, it will likely be expedient to make use of motion frames (in-band) to make the most of 802.11k neighbor studies. Please don’t confuse an 802.11k neighbor report with a decreased neighbor report (RNR). Shopper stations use 802.11k neighbor report info to achieve info from the related AP about potential roaming neighbors. The neighbor report info assists the fast-roaming course of by offering a technique for the consumer to request the related AP to measure and report about neighboring APs out there. This may additional help the 6 GHz roaming course of by informing the consumer machine of close by 6 GHz APs to which it could roam. The 802.11k neighbor report info is usually delivered via a request/report motion body alternate, as proven in Determine 5.
Determine 5 – 802.11k neighbor report
Now you would possibly ask, “How is all this going to work if there are a number of SSIDs out there from the 6 GHz radio?” For instance, an SSID for workers, an SSID for IoT gadgets, and an SSID for company, as depicted in Determine 6.
Determine 6 – Three SSIDs on 6 GHz
The excellent news is that out-of-band discovery can even relay details about the existence of a number of 6 GHz SSIDs. As proven in Determine 7, the RNR info ingredient can carry details about every out there 6 GHz SSID in a number of TBTT subfields. So as soon as once more, the Wi-Fi 6E consumer probes out-of-band to study in regards to the 6 GHz radio major channel, channel measurement, and a number of 6 GHz SSIDs.
Determine 7 – A number of 6 GHz SSID info through out-of-band discovery
So, you may additionally have seen that not one of the related SSID safety info is delivered out-of-band. The Wi-Fi 6E purchasers can get that data through varied frames as quickly as they hop on the 6 GHz channel. And also you might need additionally seen different info within the RNR ingredient, together with the A number of BSSID and Transmitted BSSID subfields. These fields are a sign that the 6 GHz radio is leveraging a number of BSSID beacon frames and probe responses.
A number of BSSID is one other functionality that was initially specified within the IEEE 802.11v modification. It reduces administration body overhead by eliminating the necessity for a number of beacons for a number of SSIDs and BSSIDs. For instance, the SSID/BSSID info for the three SSIDs of employee-6, IoT-6, and Visitor-6 could be consolidated right into a single beacon or probe response. Determine 8 reveals a packet seize of a 6 GHz beacon with a A number of BSSID info ingredient. As you may, the varied subfields can relay details about a number of SSIDs, BSSIDs, and different parameters, together with the RSN safety info of every SSID. The upside is that the data is delivered in a single beacon body as an alternative of three, decreasing Layer 2 overhead that consumes airtime. I anticipate the A number of BSSID choice for use in 6 GHz by most main enterprise WLAN distributors. May you utilize A number of BSSID in 2.4 and 5 GHz beacons? Certain, you can, however you’ll nonetheless want a novel beacon for every SSID within the legacy bands as a result of the legacy purchasers can’t interpret the A number of BSSID info. Nonetheless, A number of BSSID makes excellent sense in 6 GHz as a result of no legacy purchasers exist. By the way in which, if you wish to study extra about A number of BSSID, Adrian Granados wrote an incredible technical blog on the topic.
Determine 8 – A number of BSSID info in a 6 GHz beacon
I’ve lined a variety of subjects on this weblog…. RNR, roaming in 6 GHz, a number of BSSID, and so on. Nonetheless, I need to depart you with this final considered out-of-band discovery. In my conversations with many individuals, I discover them very proof against the considered Wi-Fi 6E purchasers not utilizing the normal in-band probing in 6 GHz and as an alternative utilizing the out-of-band discovery methodology of RNR. Nonetheless, I’ll reiterate, out-of-band discovery would be the greatest methodology. There are just too many channels in 6 GHz for the scanning strategies of outdated.
Wi-Fi 6E purchasers can nonetheless get a roadmap for six GHz connectivity, however they have to journey off-road on a unique frequency to get the mandatory info for his or her remaining vacation spot.