Re: Wierd metro WiFi problem

tyler... yup. no relationship.








http://evdo-coverage.com/cellular-repeater.html

On 1/26/06, Tyler van Houwelingen <[email protected]> wrote:
> Agreed, unfortunately this does not appear to be the case.  We can use the
> same interfaces and make the download speed change simply by increasing the
> latency between.  We look at the switches, routers, etc and there are no
> errors on the ports.
>
> a hypothesis of the problem is that maybe with an upload, the latency and
> wireless hops are at the beginning of the link, causing any retransmissions
> to be immediate.  with a download, the latency and hops are at the end,
> potentially causing retransmissions.  We dont however, detect any
> retransmissions.
>
> ty
>
>
>
> ----- Original Message -----
> From: "Jack Unger" <[email protected]>
> To: "SeattleWireless Talk List" <[email protected]>
> Sent: Thursday, January 26, 2006 12:50 PM
> Subject: Re: Wierd metro WiFi problem
>
>
> > Could be a router Ethernet port speed-mismatch issue.
> >                                                        jack
> >
> > Tyler van Houwelingen wrote:
> >
> >> I am contacting the best wireless minds I know to help with a bizarre
> >> issue that has us stumped.
> >>  Situation:
> >> - We have 4 bonded T1 lines currently for our backbone, running a large
> >> (400 AP) metro WiFi network.
> >> - When connecting directly into the backbone router, we get 6M down, 6M
> >> up as expected.
> >> - However, when we begin to add a little latency between a testing PC and
> >> the backbone connection, the upload speed stays the same, but the
> >> download gets hammered.  With 10ms of average latency from the metro WiFi
> >> network side, the speed drops to 2M down and 5M up.  At 40ms, it is
> >> around 800k/5M.
> >> - The wireless communications are more than fine as we get 8M/8M back to
> >> our headquarters from anywhere in the metro WiFi network.  The problems
> >> only come from testing into the Internet.  We get the same goofy results
> >> when we disconnect the city network completely and just add latency in
> >> the lab.
> >> - We have run all the DrTCP (MTU, RWIN) like tricks which provides some
> >> improvement, but not much.
> >>  Why would this additional latency kill the downloads so much?  I suspect
> >> the problem is with our backbone provider (Expedius) or some limitation
> >> of metro WiFi that worries me.  In our other metro WiFi network, we do
> >> not see this, but they all use a different backbone provider (AT&T).
> >>  Any suggestions to debug/fix this would be very much appreciated.
> >>  tyler
> >>  Tyler van Houwelingen
> >> Founder and CEO
> >> Azulstar Networks, Inc.
> >> 1051 Jackson, Grand Haven, MI 49417
> >> 1117 Rio Rancho Blvd 13, Rio Rancho, NM 87124
> >> 1-877-AZULSTAR
> >> www.azulstar.com <http://www.azulstar.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
> > [email protected]  (818) 227-4220  http://www.ask-wi.com
> >
> >
> > _______________________________________________
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> >
>
>
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