Re: [Condor-users] windows 7 silently drops udp when no arp entry is present

[Rob de Graaf <r.degraaf@xxxxxxxxxxxx>]

Forgot to mention: we had a similar (the same?) problem with WinXP a few 
years back:

https://lists.cs.wisc.edu/archive/condor-users/2008-January/msg00232.shtml

Adding D_NETWORK logging solved it then, but doesn't now. Maybe the 
implementation has changed, or the added delay simply isn't enough?

Thanks,

Rob de Graaf
Erasmus MC

On 07/26/2012 07:59 PM, Rob de Graaf wrote:
> Hello list,
>
> We're having a problem with Windows 7 nodes. I believe this is it:
>
> http://support.microsoft.com/kb/233401
>
> It seems the condor_master on the client tries to send an update to the
> collector. This update consists of two fragments, but only the last
> fragment is actually sent. The first fragment is dropped because there
> isn't an arp entry for the collector yet. Subsequent updates are fully
> sent, until the arp cache entry for the collector times out. At least,
> that is what I think is going on. :)
>
> I have left a ping -t running from a cmd window to prevent the arp cache
> entry from going stale, and all updates since have gone through
> completely. I can't raise the arp cache timeout, so I am thinking of
> lowering master_update_interval to act as a ping, but Windows 7 has a
> very short timeout between 15 and 45 seconds:
>
> http://support.microsoft.com/kb/949589/en-us?fr=1
>
> Less than 15 seconds seems a very short update interval. We have about
> 10,000 nodes in the pool. With TCP updates, we'd need a very large
> number of sockets and file descriptors on the collector. I don't even
> know if that would work. The manual used to recommend against it but
> seems less insistent now. Have TCP updates been improved upon lately?
>
> Thanks!
>
> Rob de Graaf
> Erasmus MC
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