Hi Jon, How do you manage traffic shaping at the edge? Thanks >>> Jon Freeman <[EMAIL PROTECTED]> 12/14/2007 12:45 PM >>>
Tim, We look at this problem from two perspectives * 1) reducing the number of drops, 2) ensuring maximum capacity per client. The calculation you*re looking at is fairly straightforward * Mbs per user desired = 20Mbs (TCP per channel) / number of users. 20Mbs is used since this is the typical data carrying capacity of 11g/11a per channel with good signal quality and normal SNR measures. If you want users to have a similar experience to what they have at home (this is a typical user*s expectation), you would try to provide about 1Mbs per user to match DSL/Cable type BB connections. This amounts to 20 users per radio. If you*re looking to substitute wireless for wired connections, you*d want to provide something >5Mbs. Also, in any case, you want traffic shaping at the edge to ensure the first TCP connected client doesn*t gain an unfair advantage*.this is due to the TCP characteristic on a shared connection to use all available bandwidth. Shaping would limit the bandwidth on a packets per second basis per station which fixes the issue and allows a fair use of the shared bandwidth. In K12 situations with laptop carts, we*ve accomplished this with multiple radios (separate non-overlapping channels) provided in every space * allows for multiple laptop carts to be used in adjacent rooms served by a single 4 radio Array (with load balancing capability). In fact, this is the only way to serve high density deployments * the best example here is the ITU (International Telecommunications Union) which sits almost 2000 users in one room. We user 4 Arrays with 15 radios each for a total of 1.2Gbs of TCP Wi-Fi capacity. Hope this helps* Regards, Jon Freeman 303-808-2666 Xirrus, Inc. From:Gruenhagen, Timothy T. Mr. [mailto:[EMAIL PROTECTED] Sent: Friday, December 14, 2007 10:14 AM To: [email protected] Subject: [WIRELESS-LAN] Classroom wireless WAP counts I am working to develop a rule of thumb number of seats per classroom WAP for our institution. I realize that it is a highly variable ratio depending on what type of applications are being run, size of room, etc. I'm considering 1 WAP per 25- 50 seats. Does anyone have a number they use for a starting point? Thanks, Tim Gruenhagen Manager of Network Engineering Miami University Oxford Ohio ********** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/groups/. ********** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/groups/. ********** Participation and subscription information for this EDUCAUSE Constituent Group discussion list can be found at http://www.educause.edu/groups/.
