WLPC 2024 PHX Day 2
Today was the second day of WLPC! Here are my notes.
Morning
This morning we had a couple of great talks about 6E and about OFDMA. Unfortunately I didn't think to bring my laptop to take notes.
Ten Talks
Radiation: Nuclear Power Plans and Wireless
Presenter: Ferney Muñoz Vergara
Topic 1: Access. Very difficult to access a nuclear power plant, as it probably should be. Differences between US and EU plants. In US is much more visible security. In the EU you have to take shoes, clothes, and EVERYTHING off to get into the secure area. Then you must pass through an x-ray scanning machine.
Topic 2: Radiation. Ionizing and non-ionizing. The aura borealis is a natural phenomena of radiation. Solar winds interact with gases in the upper atmosphere.
Non-ionizing radiation example: Fire. Fire produces "harmless" infrared radiation. Also fire, microwave, wifi and cellular. "Cellphone radiation affects cells in living humans" article suggests that there is some affect of radiation on human cells but unclear that that means it's cancer? Overhead powerlines are another form of non-ionizing radiation.
Ionizing: UV, Skin cancer. X-rays are an example of radiation shot through a person into a digital sensor that can see the shadow of the person's bones/body. Gamma radiation is the most scary one potentially.
Topic 3: Half-life. Some elemets produce radiation naturally when they decompose. Uranium for example has a half life in the billions of years.
Alpha rays can be stopped by clothes or a piece of paper. EG Polonium-210, its radiation travels about 8cm. Example of Russian guy poisoned by about 10 mg. IF YOU SMOKE YOU GET TO INHALE THIS IN SMALL QUANTITIES. Bannanas have k-40 which also produces this.
Gamma rays can also be used to kill cell cancer.
Topic 4: Chernobyl / Nuclear risks
Power of 40 nuclear bombs came from chernobyl explosion.
Symptoms of Radiation - headaches - memory failure
How to prevent it - Minimize time exposure time - Distance: inverse square law also applies to radiation - Wear a hat
This presentation concluded with a moving video from a past WLPC participant who was not able to make it due to ALS.
Work on your ideas
This presenter encouraged us to work on our ideas. "An idea is born" how to use AR for combined / wifi and cellular site surveys. Netztester 2. This can measure wifi (optional 6 ghz) and cellular. Standalone device. Test the idea.
Discussion of the web interface & floor plan. Pretty cool visualization of a familiar looking hotel room. Also scaled up to the hotel grounds.
Full device: $2k Slimmed down version: Couple hundred
DHCP Option 82 & The endless possibilities
DHCP hanshake recap. Discover offer request ack. Discover message is sent out as braodcast which does not work well with wifi protocols. A dhcp relay agent is a service that runs on the ap intercepts it as broadcast and reconstructs it as unicast.
How option 82 fits in. It tells something about the dhcp relay information. 2 sub options second id and agent id. This information can be used to filter classified clients. IN open wifi we allow this information to be vlan id ap wan mac or ssid. The server can use these to target the ip assignment. This can be as granular as assigning ip addresses by ap mac address.
Example one DHCP server on the management vlan.
DHCP exchange example presented in wireshark.
Scenario 2: DHCP Server on ec2 and ap behind nat router.
Ekahau
L'Oreal 1 millions SQ FT wearhouse (10x football fields)
Very high ceilings, lots of metal.
Requirements:
- Fully future proofed
- Fully 6 GHz Enabled
- No Support for 2.4 GHz
- Seamless Roaming
- RF Redundancy (1 ap failure is not fatal)
Different requirements for different areas.
CISCO Meraki CW Series APs
CW 9166D1 integrated dir ants also other omni antennas
must use internal dir ants
Use integrated dir ant suspended from ceiling pointing down
Used survey data to optimize existing wifi while waiting for new equipment
Just go/design, one wheel survey data
WiFi LTE a love story (sort of)
Why aren't more people using pLTE? Because WiFi has gotten so good!
pLTE can be the solution to several issues.
Converged Networking. This is a completely seperate network architecture.
Progression through the history of network automation including the rise of controllers.
The rXg Automation platform serves as both the Router and the Hypervisor of any necessary software for a converged network, EG an LTE EPC core running in Linux IN the rXg. The EPCs at each local gateway are all connected via VPN across the internet.
Shoutout to my co-workers Hubie and Shawn for an amazing presentation!
WiFi Alliance Services: Maximizing the 6 GHz Wifi opportunity
A cloud based AFC coordinator. The future is bright for WI-FI 6E and 7 solutions!
Automatic Frequency Control is something that standard power outdoor aps need to implement to control their tx/rx power.
The future of wifi connectivity and concealment
A raised access floor can have an antenna embeded in it. This gives us a bottom up approach to coverage. 6E must use internal which is more complicated to put in the floor. Solution: friendly floor tile. A floor tile that can be installed with an AP in it.
You can Hide antennas in a store. You can hide an AP in a wall. These "Junction Box Antennas" can be almost completely concealed.
Antennas can be hidden in lights.
You can hide antennas of sight. Antennas can be embedded in bollards.
You can hide antennas in a case. Mobile Wireless Case. Lithium chemistry battery. Amazing features!
You can hide antennas in outer space. Or at least in theme park rides.
Data Science, Zoom, Teams & More
Zoom and Teams are the canary in the coal mine. Data science is very important here. Latency jitter and loss are the metrics that are targetted. Bad = > 150ms latency. AI is used to determine the cause of poor performance.
Validating wifi using customer's phone
Can be used when you can't be there. This requires the customer to install your app on their phone I think.
Rethink your uplink
When your device moves away from the AP, the uplink degrades faster than the downlink.
6 Client Behavior Deep Dive
Standard Power
Standard power requires the AP to talk to the AFC. Every time the AP reboots it must recheck with AFC. Seems most likely that the AP is directly talking to the AFC, not through a controller. An AFC response is allowed to be considered valid until 23:59 the next day.
The AP can give an uncertainty factor to the AFC, the AFC can make its decisino based on the worse possible case of where the AP is. AFC will tell the AP what Power Spectral Density it can use PER CHANNEL.
AP MUST be able to contect the AFC once a day.
Standard power allows external antennas. UNII-5 and UNII-7 only.
Requring an Uplink to AFC is a design complication!
Standard power = outdoor or external antennas.
Device Classifications
Current APs are all classified as low power indoor (LPI) devices.
LPI APs and devices can only be used indoors.
FCC Terminology: - 6XD Low power indoor - 6CD Dual Client - Can use both LP & SP APs.
Behavior
A CISCO AP w/ a 6 GHz SSID will advertise FILS frames. In here is a power envelope and a short SSID present. It's kind of like a mini beacon.
CISCO Meraki send out blank beacons for a hidden ssid. This beacon is WPA2. This CISCO's mesh network for aps to talk to each other. Turn mesh networking off to make it go away.
There is one difference between a standard power beacon and a regular beacon: the regulartory info in the 6GHz operation information in HE operation.
FCC Attestation Letter
- FCCid.io
You must find your device's FCCID. On mac go to about -> regulatory certification.
First 3 chars represent manufacturer, then last chars represent device. Kind of like MAC OUI. You can search by just the first 3 chars, ie the manufacturer.
Search for attestation letter.
- Subordinate device: Must be fixed location, have direct power, and no internet access. EG mesh/extender.
More behavior
When a primary channel is a non PSC, the AP will send out beacons on all 20 mhz sub channels, not just the primary. EG an 80 mhz wide channel will have 4 beacons. 6 Ghz Operation informatin IE will have duplicate beacon=1.
80 in the SSID of the probe request
Clients can put 80 into the SSID field of a probe request to actually probe based on a short SSID in a different field fo the same probe request.