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RE: [Karlnet] Poling and performing to the lowest denominator?

To: "Karlnet Mailing List" <karlnet@WISPNotes.com>
Subject: RE: [Karlnet] Poling and performing to the lowest denominator?
From: "Rob Trout" <rtrout@t-speed.com>
Reply-to: Karlnet Mailing List <karlnet@WISPNotes.com>
Date: Tue, 12 Aug 2003 13:09:45 -0500
List-post: <mailto:karlnet@WISPNotes.com>
What versions?

-R


> >-----Original Message-----
> >From: Timothy Steele [mailto:tsteele@e-isco.com] 
> >Sent: Tuesday, August 12, 2003 11:10 AM
> >To: karlnet@WISPNotes.com
> >Cc: Marcus Rudd; Neal Boren
> >Subject: [Karlnet] Poling and performing to the lowest denominator?
> >
> >
> >We have several mountain sites with 40+ subscribers each. 
> >All running KarlNet Flash ROMs for base units and a mixture 
> >of WG+, NDIS, Ubicom units, AP-1000's for subscribers. Our 
> >base units are 1+Ghz CPU's with 256mb of RAM. Each of our 
> >mountain sites are configured in Turbocel ISP base mode. We 
> >have experienced high latency spikes evident in any ping 
> >test you perform from a subscriber's link to the mountain 
> >site itself. The pings would return >10 for 8 or so pings 
> >then spike to over 300ms then return to >10. This "spike" is 
> >even evident even when there is little or no traffic on the 
> >site. We have tested turning poling off and the spikes 
> >completely disappear. The only bad thing is the new Ubicom 
> >units are a variant of NDIS client code that requires the 
> >base units to be in ISP mode. ISP mode by default enables 
> >poling. If we disable poling we loose the ability to support 
> >the new low cost CPE's. This spike is across the board, each 
> >and every subscriber exhibits the spike.
> > 
> >            In our lab we were able to recreate the problem 
> >by adding a subscriber with a poor SNR (to the point where 
> >we began receiving failures in the remote monitor utility) 
> >It seems as long as ALL subscribers are receiving a 12db SNR 
> >consistently the "spikes" remain acceptable at 30 or 40ms. 
> >The second ANY subscriber drops below 12db SNR the latency 
> >spike begins to increase. The more unstable the link the 
> >greater the latency, again this latency is exhibited across 
> >the board. It seems that if even one subscriber is receiving 
> >a poor wireless link IT WILL affect the entire subscriber 
> >base of that site. Disabling poling seems to remove this 
> >cross susceptibility. 
> > 
> >Has anyone seen this? Is it true that a KarlNet site with 
> >poling enabled performs at its least common denominator? 
> >_______________________________________________
> >Karlnet mailing list
> >Karlnet@WISPNotes.com 
> >> >http://lists.wispnotes.com/mailman/listinfo/karlnet
> >

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