Hello Jack,
good pigtails and don't mount/position the antennas close together, then you don't see a big enough problem to counter the benefits of the four or eight port setup.
It's good to hear that the Atheros cards are well shielded however I'll bet that (unless ALL the issues mentioned above are successfully addressed) the collision/overloading/throughput reduction problem will become "big enough" to worry about when traffic on the box becomes heavy - the throughput can then degrade sharply.
A simple paragraph or two addressing this issue in your documentation would provide a very valuable service to the WISP community.
Yes, it is no problem to put this in our RouterOS documentation -- and perhaps an application note for the RB18, for those not using RouterOS.
The needs of people using this cards don't have to be -- full 8X more throughput. They can also need multple point to point connections with the full radio power of one card -- even if tx-holdoffs or receive collisions lower the throughput because of 'static' noise from other radios close.
Thanks for the support. It would be better if this discussion could take place after you and Jim had both experimented in full with the multiport cards. If locating the cards close to each other is so bad, how is it that I can get 120Mb/s of throughput from a four port card with four 5GHz radios -- on the table? It is not nice being attacked by armchair flamers -- meaning Jim, not you.
John www.mikrotik.com
Best Regards, jack
John www.mikrotik.com At 09:58 PM 9/29/2004, you wrote:
John,
I know you may disagree with what I'm about to say but using 8 radios that are physically spaced so close together is very likely going to lead to interference between the radios with consequent lost throughput.
If and only if the builder of an 8-radio system uses intelligent frequency planning (for example: Ch 1, 6, and 11 on 2.4 GHz and non-overlapping frequency selections on 5 GHz) will there be any chance of avoiding interference when the system is handling moderate-to-heavy traffic. Even then, it's going to take luck (and who can rely upon luck to secure their livelihood?) to keep the interference down and the throughput up.
My suggestion: Include advice and guidance on this topic in your documentation.
jack
John Tully wrote:
The eight port mpci to pci cards main use would be to easily use eight radios in you AP platform. This should be quite useful for multiradio APs with your choice of software.
John
www.mikrotik.com
RouterBOARD 18 -- 8 port mPCI to PCI board (Extreme)
http://www.routerboard.com/rb11.html#rboard18 (the back side has four ports also - tomorrow, both sides will be shown)
Price: $120 List
John www.routerboard.com www.mikrotik.com
-- Jack Unger - 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 Next 2-Day Hands-On WISP Workshop October 20-21 in Phoenix AZ [EMAIL PROTECTED] (818) 227-4220 http://www.ask-wi.com
-- Jack Unger - 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 Next 2-Day Hands-On WISP Workshop October 20-21 in Phoenix AZ [EMAIL PROTECTED] (818) 227-4220 http://www.ask-wi.com
