Dartmouth plans video, VoIP on its Wi-Fi network: Dartmouth is the college that discovered nearly two years ago that it's cheaper to offer free U.S. long-distance calling to all campus lines than it was to manage the accounting and billing process for said service. Last year, they started trying VoIP over Wi-Fi using special phone. Now they're planning for video over 802.11a and a more rapid transition to VoWLAN calling.
Dartmouth chose 802.11a not just because it lacks interference from lots of non-WLAN devices, but because they are using 802.11b-based VoIP phones, which means that these phones can steal quite a lot of time slots at each access points just by being in use if they had gone with 802.11g for video. Instead, video will stream at 802.11a, while voice and data can remain on 802.11b and 802.11g. (A commenter below notes that the article incorrectly states that the entire network drops to 11 Mbps when an 802.11b device associates: in fact, the 802.11b device just takes up more "space" on the network reducing the ability of 802.11g devices to broadcast by reducing the amount of open signal time.)
The network will quadruple access point raw numbers to get the density right to support Wi-Fi. They're switching from Cisco APs to an Aruba WLAN switch-based architecture to provide better signal and data flow management.
Dartmouth is also aggressively pushing VoIP: 4,000 of 7,000 phone lines on campus are VoIP, but the article notes just a few hundred use Wi-Fi. That's set to change, too, and they may adopt Vocera communicators based on the a reference in the article.
The article states:
"If an 802.11b device associates with an access point, the access point drops down to 11M bit/sec for 802.11g users."
That is incorrect. 802.11g stations are still able to transmit at speeds up to 54M bit/sec when 802.11b stations are associated to the same access point.
Great job with WiFiNetNews. I visit almost every day.
Ben