VoIP is UDP.  Also latency variation or out-of-order packets are bad so there 
is no retry mechanism at transport or application layer.  So the packet gets 
one chance for delivery, otherwise it gets dropped, and there goes 10 ms of 
voice.

airFiber already prioritizes packets based on COS and DSCP values, so VoIP 
packets would typically be prioritized for example if DSCP=46.  Plus it’s 
fairly common to send beacons and retries at a lower modulation.  So all the 
pieces of the puzzle would seem to already be there.


From: Josh Reynolds 
Sent: Saturday, September 10, 2016 4:05 AM
To: [email protected] 
Subject: Re: [AFMUG] airFiber error correction

For you first part, I don't know.

For your second part, I have never heard of a feature like this - normally that 
would be handled by TCP for most use cases and not a layer1 device.


On Sep 9, 2016 11:35 PM, "Ken Hohhof" <[email protected]> wrote:

  I am going to assume airFiber has some sort of FEC, but does anyone know if 
it has a retry mechanism (ARQ)?  And if it does have ARQ, what is the impact on 
latency, and can retries result in out-of-order packets?

  And has anyone ever heard of a manufacturer offering the option of having 
high priority latency sensitive traffic sent at a reduced modulation rate to 
insure it gets there the first time? 

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