For Ethernet colision detection type networks, you are correct. That is what many WISPs forget when deploying PtMP. They incorrectly think a CDMA 25mb link will double their 10mb TDD link as they scale. They learn that as customer get added, the capacity is not nearly as much as they thought..
But with Ethernet backbones it does not always work the same, for two reasons.... 1) There is only one end device, so its not possible for collisions, and collision avoidance algorythms aren't really needed. 2) If using TDD Ethernet, transmits are scheduled, without the typical overhead of Ethernet. I can run successfully run a bandwidth test of 95mb over a 100mb Cogent fiber circuti, and with a Tlink-45 set 36mbps mod, tested to pass 30mbps with radio tests, I can count on passing 30mbps through it. So again, it comes down to the design and technology of the backbone. Tom DeReggi RapidDSL & Wireless, Inc IntAirNet- Fixed Wireless Broadband ----- Original Message ----- From: "Scott Reed" <[email protected]> To: "WISPA General List" <[email protected]> Sent: Thursday, May 20, 2010 11:08 AM Subject: Re: [WISPA] Bandwidth > Old rule of thumb for Ethernet, because it is based on collision > detection, is 70-75% is the max you want. Above this and collisions > often become an issue. I assume the same is true for the faster links > as well. > > Jeremie Chism wrote: >> At what percentage of your backbone usage do you look at adding more >> capacity. At peak times I run at 65-70 percent of capacity. Just >> looking for suggestions. >> >> Sent from my iPhone >> >> >> -------------------------------------------------------------------------------- >> WISPA Wants You! Join today! >> http://signup.wispa.org/ >> -------------------------------------------------------------------------------- >> >> WISPA Wireless List: [email protected] >> >> Subscribe/Unsubscribe: >> http://lists.wispa.org/mailman/listinfo/wireless >> >> Archives: http://lists.wispa.org/pipermail/wireless/ >> >> >> > > -- > Scott Reed > Sr. Systems Engineer > GAB Midwest > 1-800-363-1544 x2241 > 1-260-827-2241 > Cell: 260-273-7239 > > > > -------------------------------------------------------------------------------- > WISPA Wants You! Join today! > http://signup.wispa.org/ > -------------------------------------------------------------------------------- > > WISPA Wireless List: [email protected] > > Subscribe/Unsubscribe: > http://lists.wispa.org/mailman/listinfo/wireless > > Archives: http://lists.wispa.org/pipermail/wireless/ -------------------------------------------------------------------------------- WISPA Wants You! Join today! http://signup.wispa.org/ -------------------------------------------------------------------------------- WISPA Wireless List: [email protected] Subscribe/Unsubscribe: http://lists.wispa.org/mailman/listinfo/wireless Archives: http://lists.wispa.org/pipermail/wireless/
