The Packet Pushers published a podcast where we discussed the future of WiFi services in public spaces following the recent court case where Marriot was fined $600K for blocking WiFi inside a conference centre. The issue is much more complex than the simple knee jerk reaction of “greedy capitalist pigs want all the money and why isn’t the government doing something about it” because WiFi remains inherently unreliable and permits blocking and service disruption.
- The growth and success of WiFi is largely based on access to a small amount of spectrum.
- That spectrum is open-access, shared and easily abused (deliberate or not).
- WiFi standards are insecure, unsafe and unprotected.
- Companies that offer services over WiFi cannot offer guarantees in a shared medium
- Customers who are paying for services have expectation of guarantees service delivery.
- There are no winners on this issue.
Offering a WiFi Service
Consider a business offering a commercial WiFi service such as most hotels. When customers pay for WiFi they have an expectation that the service will function as promised and when the service is not delivered will complain. Companies who organise conference want to have high quality WiFi service to offer their attendees. Hotels want to offer a WiFi service to guests.
What happens to this commercial service when the WiFi service is interrupted, blocked or subject to some form of interference. Well, wireless interference comes in two types – frequency and designed protocol features.
The spectrum used by for WiFI is open access and free for any purpose. Any device can legitimately generate signals in the 2.4Ghz and 5Ghz spectrum including non-digital products such as surveillance video cameras, baby monitors and so on. A radio spectrum is a shared medium. That is, any device propagating a signal in the smae frequency spectrum is using the “bandwidth”. When there are many devices using the same ranges of frequencies the spectrum, the radio signals will
To make matters more complicated, the spectrum is only “used” in a specific physical space because radio signals attenuate at a rapid rate  that increases exponentialls. Radio spectrum interference can seem to be random because it varies according to distance from source, strength of signal and sensitivity of receiver.
This is important. Higher quality and large scale WiFi installations increase the density of WiFi base stations but must use low power radio transmitters to ensure that neighbouring units have a physical space to process signals.
WiFi Ethernet Standards Are Designed to Enable Blocking
Part of the IEEE 802.1 standards for Wireless Ethernet is a section that allow for “wireless security”. A number of features were developed for Enterprise companies so that any unauthorised WiFi units can be located, blocked and/or disrupted from operation. Part of the Ethernet wireless signalling between wireless clients and basestations uses an unencrypted signalling protocol to negotiate the connection. Base stations can send what amounts to a forced disconnection request to any client connecting to any base station. This is often called “Enterprise Wireless Security” and represents a high profit market segment for WiFi vendors.
Hard Choices, Few Options
This topic is going to become much more urgent in the years ahead. Service guarantees are critical if WiFi products will be offered to consumers. Carriers like BT, Comcast and Free.fr are offering commercial WiFi from household hotspots to offer roaming WiFi. Restaurants, bars and clubs offer WiFi to encourage customers to use social media to promote their venues. The uncontrolled and unregulated spectrum allows rapid growth and adoption at low cost. At the same time, lack of controls over radio spectrum mean that there are no guarantees that wireless will work.
- When a radio signal loses its strength, this is called attenuation. ↩
Other Posts in This Series
- Analysis: CloudFlare Keyless SSL Scales Down Internet Connections (13th March 2015)
- Analysis: Marriot Court Case Highlights the Problems of WiFi Services (12th March 2015)
- Analysis: Example of WAN Orchestration (25th February 2015)