[IDD #AZJ-636742]: Help with (again...!) very high ldm latencies

Hi Luis,

I apologize for taking so long to get back to you...

re:
> First of all: I'm sorry for, every year, sending you an email about the
> issue on the subject. It's frustrating to face the cyclical nature of
> this problem, to keep asking the communications guys (one of them on
> copy)  for responsibilities and get a "sorry, it's not our fault/there's
> nothing we can do about it" over and over again.

Do you know where the bottleneck is?

re:
> As you can see, our host atm77-fis.clients.ua.pt is having (or keeps
> having...) very high latencies for the 06,12 and 18z cycles of the
> CONDUIT stream.

These correspond to the volume peaks for the global GFS data.  If
there is some sort of volume limiting on the connection (e.g., packet
shaping, etc.), it would show up during these data volume peaks.

re:
> Lately, the machine was migrated to a new network (a
> "server" network), and my fingers were crossed, hoping that this
> migration could raise latencies.

I trust that you mean lower latencies... we define latency to be the
difference in time from when a product is first made available in the
IDD to the time it is received at the end-user site.

re:
> Not at all...the song remains the same.
> For instance, at the time i'm writing this email to you (11:56
> localtime) i get, from ldmwatch
> 
> Apr 01 10:56:25 pqutil INFO:   244450 20110401102330.955 CONDUIT 011
> data/nccf/com/gfs/prod/gfs.2011040106/gfs.t06z.pgrb2f153
> !grib2/ncep/GFS/#000/201104010600F153/HGHT/30 hPa PRES! 000011

And no more?  This is only one product, but the apparent latency for
this product is on the order of 30 minutes.  This is, of course, not
good.

re:
> Since this high latency is compromising my daily operational activities,
> I would deeply appreciate if you suggest something that I might ask to
> the communications guys to tackle this issue. I'm really tired of not
> being able to fully understand the nature of this problem and, moreover,
> its solution.

First, a couple of questions:

- can you send us the ~ldm/etc/ldmd.conf REQUEST line(s) you are using
  to request CONDUIT data?

  In particular, I am looking to find out which IDD upstream machine(s)
  you are requesting CONDUIT data from, and if you are splitting your
  feed REQUEST into multiple mutually-exclusive subsets.

- can you tell us exactly which portion of the CONDUIT data you want/need
  for your activities?

re:
> Mind do give me a hand on this?

Not at all.  Responses may be somewhat slow this week as I am heading for
Vienna, Austria for the EGU 2011 General Assembly.  I will be checking
email as much as possible, but there will be times when I will be occupied
with the conference.

re:
> Thank You very much in advance.

No worries.  We will do all we can on this end to get you the data in
a timely manner.


Cheers,

Tom
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Ticket Details
===================
Ticket ID: AZJ-636742
Department: Support IDD
Priority: Normal
Status: Closed