Jack, Well said. Some have been saying this for years. Load testing should be a mandatory category of wisp test procedures but it seldom is even considered. Brad
-----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Jack Unger Sent: Wednesday, February 14, 2007 11:42 AM To: WISPA General List Subject: Re: [WISPA] multi-radio Wi-Fi base stations Matt, I advise using only thoroughly tested hardware. Often when using multiple radios in a single enclosure there will be interference issues that will only become apparent when the radios become heavily loaded and have to deliver high throughput. If you deploy without full throughput testing (either your custom-built product or someone else's product) you may think everything is fine until the throughput load(s) start building up and then you'll find that the box will not deliver the throughput that you expected from the multiple radios. This interference happens because of leakage from card to card. Even though cards are on different frequencies, enough wireless energy can leak across cards to desensitize the receivers, causing packet loss, packet retransmissions, and reduced throughput. I expect you will get several comments from people who will advise you that they have several radios in one box and "it's working great". Either they have a good engineering staff that knew how to carefully engineer and design the entire box with excellent RF shielding between the multiple cards or (much more likely) they do not understand the issues of RF leakage, receiver overload, and the consequent throughput reduction and they HAVE NOT TESTED their "solution" under conditions of heavy loading so they don't realize the shortcomings of their design. In summary, it may be more inconvenient to use separate (well shielded) metal enclosures for different Wi-Fi (or other) radios but using separate enclosures will give you a MUCH HIGHER CHANCE of achieving full throughput from each radio. Throughput is of course what customers pay WISPs to deliver so WISPs are advised to consider the costs of both technician labor and (lost) business reputation when making multiple-radio Wi-Fi hardware decisons. Respectfully, jack Matt Liotta wrote: > We don't do much Wi-Fi, so I figured I would ask the list. If I wanted > to deploy a number of Wi-Fi radios at the same location what kind of > setups are available? I am looking for something where I can deploy one > physical box that has multiple radios as opposed to a single box per > radio. Ideally, it would be something modular where I can have a > variable number of radio interfaces by simply adding cards. > > Does anything like that exist? > > -Matt -- Jack Unger ([EMAIL PROTECTED]) - President, Ask-Wi.Com, Inc. Serving the License-Free Wireless Industry Since 1993 Author of the WISP Handbook - "Deploying License-Free Wireless WANs" True Vendor-Neutral WISP Consulting-Training-Troubleshooting Newsletters Downloadable from http://ask-wi.com/newsletters.html Phone (VoIP Over Broadband Wireless) 818-227-4220 www.ask-wi.com -- WISPA Wireless List: wireless@wispa.org Subscribe/Unsubscribe: http://lists.wispa.org/mailman/listinfo/wireless Archives: http://lists.wispa.org/pipermail/wireless/ ************************************************************************ ************ This footnote confirms that this email message has been scanned by PineApp Mail-SeCure for the presence of malicious code, vandals & computer viruses(190). ************************************************************************ ************ ************************************************************************ ************ This footnote confirms that this email message has been scanned by PineApp Mail-SeCure for the presence of malicious code, vandals & computer viruses. ************************************************************************ ************ ************************************************************************************ This footnote confirms that this email message has been scanned by PineApp Mail-SeCure for the presence of malicious code, vandals & computer viruses. ************************************************************************************ -- WISPA Wireless List: wireless@wispa.org Subscribe/Unsubscribe: http://lists.wispa.org/mailman/listinfo/wireless Archives: http://lists.wispa.org/pipermail/wireless/
