[evla-sw-discuss] model propagation idea

[Kevin Ryan]

Barry's worst-case scenario for sending delay models to the  
correlator specified about 5 models/sec per Station Board.  I did  
some testing on Friday with a CMIB here in the office and found that  
it could handle a good 50 models/sec even using the REST/TCP  
interface so that should be no problem.

Where we are concerned is with the MCCC re-distributing these 600  
models/sec.  Barry's testing indicated that processing at that rate  
taxed his machine quite a bit.  This processing would be of the form  
of parsing model XML, reading an Antenna/Baseband id, mapping that to  
a rack/crate/slot, and then sending it off to it.

Bruce and I discussed a possible way to re-distribute the models  
without the MCCC having to parse the XML and I would like to get your  
thoughts about it (especially Barry's).

The idea is to map port numbers to antenna and baseband numbers.  We  
would use a block of 128 ports, each one mapped to a particular  
antenna/baseband.  The MCCC would listen on all 128 ports and know  
which station board to send the delay to based on which port it was  
received on.  In other words, the outside of the VCI would see the  
ports as antennas and basebands and the inside would see them as rack/ 
crate/slot destinations.

Since Barry would ignore any responses from the VCI for delay models  
anyway, and since he and Ken indicated that it is no big deal if a  
few models are dropped, then I suggest that we just keep it unicast  
UDP between the Executor and the VCI.  I'll probably continue with  
the REST/TCP that is currently in use with the CMIBS unless we see a  
need to change it.

Does anybody have issues with this port mapping scheme or the unicast  
UDP between Executor and the VCI for the delay models ?


Kevin