Thanks Peter.
As Bernard suggested, a LOT of bandwidth there. Presuming a single channel P-P link with a modest 1:1 efficiency, a modest 2:1 PBX oversubscription and a 2:1 voice compression scheme (for 32kbps duplex), you'd get about 10K phone lines out. So if a link was reduced from rain fade (beyond the dB margin allowances) by a factor of 10, this would still provide ~1K voicelines - a seemingly not unreasonable lifeline link. Further, we have heard of much higher channel efficiencies such as 2.5:1, PBX oversubscription is usually more like 3:1 to 5:1, and I'm not sure how much compression we can perform and still have toll quality voice, but probably better than 32kbps duplex. Then there is the step down (does this necessitate multiple mod schemes in the same electronics, or can QAM16 "step down"
without switching to QPSK?).
All in all, seems there would be ample room to maintain lifeline voice under severe weather conditions.
I was intrigued in one of the tutorials which suggested that a hurricane could knock out a 4-6GHz link. If it knocks out THIS large of a wavelength, what'd it do to 38GHz? And would the above techniques be able to override such conditions?
<..QoS/CoS aware nodes would (e.g. Stanford Broadband Wireless, Triton Network Systems)...>
Well, QoS can only guarantee it if it SEES it.
<..does anyone know how to maintain Netscape read cache when posting a reply? (My messages read are erased when I post)...>
Not sure what you mean here Peter. Browser cache doesn't change the "messages read". If I understand what you are asking, messages are tracked by SI. Each time you click into a thread that you are watching, whether you read the posts or not, SI notes and saves the last message in that thread as your last read messages. If that is not what you are asking, I'm happy to take another stab at it.
Regards-
Steve |
