Cisco Mobility Seminar
January 21, 2011 2 Comments
The introductory session started from the Borderless Networks concept: “Connect anyone, anywhere, on any device – securely, reliably, and seamlessly”.
There are more and more mobile devices; during the next 5 years 7.7 billion Wi-Fi devices are expected to be in use. In 2012 there will be more laptops than desktops, and even more smartphones/tablets than laptops. If laptops might still be equipped with Ethernet ports, the mobile devices will have no other connections than wireless.
The presence of mobile devices in enterprise environments is a reality, and when enterprises do not take active measures to promote them, the employees are bringing their own mobile devices at work and try to make the best use of them. This gives new meanings to real-time collaboration, anywhere productivity and workforce flexibility. People want to be able to access the company intranet with any device, from anywhere at anytime. Cisco marketing coined a very nice phrase to describe it: “work is an activity, not a place to go”.
With so many wireless devices simultaneously active, the 2.4 GHz and 5 GHz bands become more and more crowded, sometimes leading to total deadlocks (see the Steve Jobs difficulties to go online during the iPhone 4 presentation).
Cisco conducted some studies and discovered that Wi-Fi connection problems can have multiple sources, some quite unexpected.
In addition to other neighbouring Access Points, significant problems are caused by:
- video surveillance cameras: some of them continuously use multiple channels, with relatively high power, sometimes completely disturbing Wi-Fi links;
- microwave ovens: although theoretically shielded, the 1000W magnetrons are radiating right in the middle of the 2.4 GHz band and it is very likely that leakages will affect nearby communications;
- DECT phones: it was hard to believe even for Cisco specialists, but some of the DECT phones severely affect Wi-Fi links;
- Bluetooth: with it’s inherent mechanism to jump from channel to channel, interference with Bluetooth, especially when transmitting at 100mW, can be very tricky and difficult to diagnose.
As a major network player, Cisco acknowledged the difficulties of managing wireless connections and come with a technology called CleanAir. What Cisco did was to add a dedicated spectrum analyser to their newer Access Points. The Wi-Fi bands are scanned with a 78KHz step, and the computed profile is analysed in real-time to detect interferences. In less than 10 seconds after a problem is detected, the Access Point switches to another channel, and the troubled channel is blacklisted.
Voice over WLAN
After voice over IP became ubiquitous, the next step is to pass voice over wireless connections, and allow the use of Wi-Fi phones as GSM phones. The requirements for voice (latency < 150 mS and loss < 1%) are quite hard to meet for Wi-Fi links, and special Quality of Service techniques are implemented; traffic is prioritised in 4 queues (voice, video, best effort, background), call admission is strictly controlled to do not degrade the quality of existing calls, roaming algorithms are implemented to smoothly pass the user from one AP to the other.
Outdoor Wireless Mesh Networks
A big surprise was the presentation of existing solutions for large outdoor Wi-Fi mesh networks. Special algorithms like LWAPP are used to configure and manage Wi-Fi networks. Nodes talk to each other and the topology is automatically reconfigured when various links change status.
Large Wi-Fi networks are implemented in campuses, in large squares, stadiums, in different cities like Luxembourg, and there is even a project to cover the entire Kuwait!
One of the speakers presented us an interesting usage case: his 21 years old son. Since he was introduced to computers, all the devices he ever used were wireless, and he has no idea what Ethernet is. He is one of the Millennial kids, and we were warned that we, the audience, as representing the industry, should prepare ourselves to satisfy their needs in order to hire them.
In conclusion, regardless the actual technology in use, one thing is certain: the future is online and wireless.