[comm] Communications meeting Wednesday

[James Robnett]

    Again, not sure if anyone cares but attached is the
'key' into the drawing I forgot to include.  It's very
much a work in progress ... which is why the last sentence
just wanders off into the distance.

    Since the comm meeting there's some new insight into the
VLBI phased array outputs whose existence had previously
consisted of 'what the heck are those and where do they go'.

    They go to yet another 100+ port Gbit switch which has
10gbit outputs either into the CBE switch or a Mark5-c or both.

    There's an order of magnitude disconnect since the input
bandwidth of a Mark5-c is 4Gbit (over a 10gbit line) and the
output bandwidth of those 128 phased array boards is 32Gbit
(256mbit/board) unless they don't mind dropping bits all
over their new clean floor there's some normalization that
needs doing.  We may put a bit scrubber in to make sure any
dropped bits don't get blown around the room and mess up
the filters or get on their expensive home grown boards.

   It may be we'll only use 1 racks worth (16 boards) at
which point we can feed it straight into the 6509 and don't
need another switch, still figuring that bit out.

James

James Robnett wrote:
> 
>    BTW,  I've attached a network drawing for the EVLA
> correlator .. still a work in progress.
> 
> James
> 
> Gareth Hunt wrote:
>> There will be a communication meeting this Wednesday at 
>> 18:30UT/13:30ET/11:30MT.
>>
>> Agenda and detailed meeting locations may be found at:
>>
>>   https://wiki.nrao.edu/bin/view/Ccs/CommunicationMeetingAgenda
>>
>> Cheers,
>> Gareth.
>> _______________________________________________
>> Comm mailing list
>> Comm at listmgr.cv.nrao.edu
>> http://listmgr.cv.nrao.edu/mailman/listinfo/comm
> 
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