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[LDM #ZRD-827043]: LDM flooding pipe

Hi Michael,

> This morning we expanded our data transfer capability by increasing the size
> of the pipe between our regional HQ and the forecast offices we support.
> We've found that when a forecast office LDM requests data, the data transfer
> fills the pipe.  Our forecast offices requests are essentially flooding our
> network.
> My question is, is there a way to limit the amount of data or the
> rate of transmission a downstream LDM can have?

The LDM has no throttling mechanism for delivery of data.  In fact, the
LDM is optimized to deliver as much data as possible as fast as possible.

The site requesting the data (e.g., the forecast offices you are supporting)
can, however, alter what they request and use less bandwidth.  This would be
done by them:

- deciding exactly what they need/want

- crafting ~ldm/etc/ldmd.conf REQUEST line(s) that reflect that decision

- stopping and restarting their LDM

> We are working on a router policy which will control the data rate at the
> router, but we wonder if LDM can be configured to limit the transfer rate or
> amount.

No, not at the upstream (the site sending the data); yes, at the downstream
(the site requesting the data).


A packet shaping approach (router policy) can have the unintended side effect
of limiting the ability of the downstream's ability to get data in a time
critical fashion.  This would, of course, depend on how the limiting is
done.  We can talk more about things that might work best if you like...


Unidata User Support                                    UCAR Unidata Program
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Ticket Details
Ticket ID: ZRD-827043
Department: Support LDM
Priority: Normal
Status: Closed

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