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[LDM #CSZ-262645]: errant LDM REQUESTs on sirocco.srcc.lsu.edu



Hi David,

I was out of the office yesterday, hence the delay in my rely below...

re:
> The setup was left as is (sirrocco and pavan are not on the HP router), so
> its strange the problematic issues have resurfaced.

We do not understand what is happening at all.  Our best guess is that
there is some other piece of equipment at SRCC or LSU that is causing
slowdowns in the deliver of data by upstream LDMs that are outside of
SRCC and/or LSU.

re:
> Since our conversation yesterday on the phone, today, we have in earnest,
> started conversations with LSU's networking folks about re-evaluating our
> routers/switches. I will send them one more reminder tomorrow to get to the
> bottom of this.  Will keep you posted,

Excellent, thank you!

In the interim, I commented out the REQUEST on sirocco to idd.unidata.ucar.edu
as this REQUEST has caused problems on each node of the idd.unidata.ucar.edu
cluster to which it was directed by LVS.  Each time the REQUEST was directed
to a new node, that node experienced a equivalent denial of service attack
by the excessive number of repeat REQUESTs that would be made while existing
upstream "send" processes were still active.

I think it may be interesting/instructive to try feeding from a different
upstream that is a) not running a clustered toplevel relay node and b) is
running their LDM under Linux and c) that we have login access to.  I
will likely perform this test sometime today, and I will let you know
the results.

Cheers,

Tom
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Ticket Details
===================
Ticket ID: CSZ-262645
Department: Support LDM
Priority: Normal
Status: Closed


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