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Re: Data latencies: could much of this be avoided? (fwd)


===============================================================================
Robb Kambic                                Unidata Program Center
Software Engineer III                      Univ. Corp for Atmospheric Research
address@hidden             WWW: http://www.unidata.ucar.edu/
===============================================================================

---------- Forwarded message ----------
Date: Mon, 13 Dec 1999 18:57:36 -0500 (EST)
From: C. Vandersip <address@hidden>
To: Gilbert Sebenste <address@hidden>
Subject: Re: Data latencies: could much of this be avoided?

Interesting note Gilbert.  Can anyone provide some concrete answer to
this?  We currently have our feed request set up using the following
format:

e.g., 
      request WMO|FSL2       ".*"    yang.sprl.umich.edu

The LDM Config Checklist from the Workshop has the format as:

        request UNIDATA  ".*"  bar.bar.edu

Would it be better to split into:

        request IDD|DDPLUS ".*"  bar.bar.edu
        request HDS        ".*"  anothersite.edu

Are you're results still holding, Gilbert?

Regards,

Chris   
         ###############################################################
         #                      Chris Vandersip                        #
         #        Computer Research Specialist/Dept. Sysadmin          #
         #  Rm. 024, Dept. of Meteorology, Florida State University    #
         #          address@hidden   (850)644-2522                     #
         ###############################################################

On Fri, 10 Dec 1999, Gilbert Sebenste wrote:

> Hello all,
> 
> One of the things that was a hot topic in the UNIDATA Newsletter this fall
> was the worry of the data feed latencies via the LDM.
> 
> While I know they are going to go a different route in the future sometime
> to handle faster feeds, I'm wondering if there isn't something we can do
> right now to stop a lot of the problem we're seeing.
> 
> Pete Pokrandt reminded me during the NOAAPORT circuit board fry to split
> the NP feed into two when you request it from a site, channeling the data
> into two pipelines instead of one. He does it, and he doesn't get
> latencies (he's inside the same building, granted). That is, when you
> request NOAAPORT data from a site, do this:
> 
> request IDS|DDPLUS noaaport.serverwhatever.atmos.edu
> request HDS 10.30.28.22
> 
> I forgot all about this...and since I started doing it today, there have
> been no problems. Granted, traffic is a tad lower today on our partial T3,
> but not by very much. And, for the first time, we're not getting
> latencies. We were only getting them in the afternoon, and not fatal;
> usually around 30-45 minutes. But now, they've disappeared. That even with
> a scrambled full NIDS feed coming through the pipeline on the SDUS5*
> headers (downstream sites, I'll get rid of those shortly...sorry about
> that). That means I know I'll be able to handle the data feed on October
> 1...and I want ALL the NIDS data from ALL the sites. So I'll be sucking in
> anything with SDUS5* on it. 
> 
> Just a suggestion for those who are having trouble. Maybe the latencies
> are mainly LDM created, as opposed to net-congestion.
> 
> And maybe I'm full of it. But I wonder how many of us are doing it, and
> if everyone did it, would it help stop the latencies?
> 
> *******************************************************************************
> Gilbert Sebenste                                                     ********
> Internet: address@hidden    (My opinions only!)                     ******
> Staff Meteorologist, Northern Illinois University                      ****
> E-mail: address@hidden                                 ***
> web: http://weather.admin.niu.edu                                      **
> Work phone: 815-753-5492                                                *
> *******************************************************************************
> 
> 
>