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Re: [Karlnet] Ping time differences

To: Norm Young <npyoung@applegatebroadband.net>, Karlnet Mailing List <karlnet@WISPNotes.com>
Subject: Re: [Karlnet] Ping time differences
From: Chris Conn <cconn@abacom.com>
Reply-to: Karlnet Mailing List <karlnet@WISPNotes.com>
Date: Fri, 22 Aug 2003 11:16:16 -0400 (EDT)
List-post: <mailto:karlnet@WISPNotes.com>
On Fri, 22 Aug 2003, Norm Young wrote:

> I've been noticing some rather serious jitter between our client stations and 
> our NOC or AP.  When I ping from the client radio out towards the NOC or AP, 
> I see anything between 15mS-300mS.   The ping time jitter has no correlation 
> to system load, but responds well if I load the client that I'm testing from. 
>   (Start a download from the NOC towards the client, and the ping times drop 
> down to 20-30mS )   Pinging back from the NOC to the client, I see stable 
> 10mS or less ping times.   I've upgraded all the radios in the network up to 
> v4.43, and have the latest firmware on the radios themselves (PRISM 2.5).  
> I've even replaced radios to see if that fixes it.   The AP is a AP1000 
> running base, has two radios in it, one PtP backhaul, and the other PtMP.   
> Anyone have any idea what this could be?   Is it even a problem?
>

Probably not a problem.  The newer polling algorithm I understand is
somewhat adaptive; if your client is not doing anything, the base station
can care to other tasks.

Besides, ICMP round trip times are not really a benchmark of speed.  As
you can see yourself, do something and they become more stable.  Not
always easy to explain to someone who does not want to listen, however you
can't judge link quality by the fact the RTT time is not continuous in a
system that is designed to adapt to network load sharing.  Resources would
be wasted to preserve the "impression" of network performance...

PS, I am interested; what firmware version do you consider good to use on
the Prism2.5 cards?

Chris


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