The Gathering Technical blog

Wireless

26 Mar 2013, by Bjørn Petter Kysnes from

This year, we are deploying access points at every edge switch. This is not the first year with wireless at TG, but in the previous years, the access points were mainly installed in the main hallway between the rows.

From the past years, we have made the following observations:

  • There is a lot of interference on the 2.4GHz-band, mainly due to participants' own access points/wireless routers, Bluetooth, wireless headsets, keyboards, mice, console controllers, etc.
  • The design of the ship itself makes a difficult radio environment. The number of people moving around, participants' shelves places among the rows, sponsor stands and stalls, also affects the wireless negatively.
  • The 5Ghz band has significantly less inference but it has less reach than the 2.4GHz band, and the main issue is the number of clients per access point.

To combat these issues, Cisco has decided to lend us a whole lot more access points. This will allow us to place an access point at every participant switch, and all of the access points will be CleanAir-enabled. CleanAir is a Cisco technology to help work around difficult radio environments, and basically it means that every radio has a built-in spectrum analyzer to detect interference, analyze it, and try to work around the issue in cooperation with the other access points. We also have something called a Cisco Mobility Services Engine, which uses the access points to triangulate and locate users, other access points, interference sources etc. on a map. More on this later when we have added all of the Access Points, but currently it looks like this:

PI map

Since we have so many access points, each access point will have a very low coverage area, which means 3 things:

  • Fewer clients per radio, which gives us more reliability and better throughput
  • Less interference from the ship
  • Interference sources will impact fewer users

This does not guarentee success however, and to improve the experience for our 2.4Ghz users, please note the following:

  • Bluetooth impacts all wifi channels on the 2.4GHz band. Technically Bluetooth uses something called Frequency-hopping spread spectrum, and though a single Bluetooth client will have low impact, imagine what 5000+ Bluetooth devices will do... Therefore, avoid using Bluetooth if possible, and disable Bluetooth on your device.
  • 2.4GHz has 3 non-overlapping channels by default; 1,6 and 11. Therefore, please do not set up your own 2.4GHz access point. It will not work, and it will only have a negative impact on a already bad radio environment.
  • Use wired cable, mice and console controllers if possible. This will not only help us create a better wireless network, it will probably be less frustrating for you as well.

For the 5Ghz-network, it will probably work a lot better, but please, do not set up your own 5GHz access point neither. Consumer grade wireless routers and access points sometimes make bad decisions when it comes to channel selection and transmit power.

We have set up two SSID's that you can connect to; "The Gathering 2013" which is both 2.4GHz and 5GHz, and "The Gathering 2013 5GHz", which is obviously 5GHz only. If you can see "The Gathering 2013 5GHz" on your device, this is the one you should connect to. Both SSID's are set-up with WPA2 Personal, and the passwords are "Singularity".

Bjørn Petter Kysnes

About

TG - Technical Blog is the unofficial rambling place of the Info:Systems, Tech:Net and Tech:Server crews from The Gathering.

Filter posts by crew

Related sites

Collaborators