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What does Sticky Decision Function DO?

Question asked by Greg Harewood on Jan 22, 2018
Latest reply on Feb 20, 2018 by Günther W. Albrecht

I've only just realized I don't know the answer to this after many years with the product.

 

Without SDF, the following happens:

  •   Connection 5-tuple -> hash function -> last 8(?) bits determine bucket -> connection processed by fw with bucket

 

WITH SDF, what changes?  We know in particular that...

  • Acceleration is neutralized
  • It copes better with NAT (tho docs say static manual NAT only, oddly)

 

So, best guess....it does ONE of...

  1. Attempts to process NAT rules on mid-TCP packet before determining a bucket
  2. Relies on a synced state table to actually check the table, and only then decides whether it is the right node to process the packet to completion
  3. Tries to optimize the source port in NAPT so that it goes in the right bucket for return traffic (unlikely)
  4. Some unknowable combo of the above.

 

Not only is the documentation terrible for this (it talks about what SDF might do for you without any hint about how), but no-one even seems to have talked about this.  Google turns up nothing.  Dameon Welch-Abernathy (or anyone) - can you give us a definitive answer?

 

Thanks!!

Greg

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