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[STDS-802-16] Comment 019



Title: Message
I've had a thought in the back of my mind that we must meet is some requirement on the likelihood of a MAC delivering an undetected error to the MSAP.
 
I went searching, and its in IEEE 802-2001.
 
"
c) The probability that an MSDU delivered at an MSAP contains an undetected error, due to operation
of the MAC service provider, shall be less than 5 × 10-14 per octet of MSDU length.
NOTE—For example, (a) the worst-case probability of losing a maximum-length IEEE 802.3 frame (1518 octets) through physical-layer damage is to be less than 1.21 × 10-4, or approximately 1 in 8250; (c) the worst-case probability that a similar frame, which contains an MSDU of 1500 octets, is delivered with an undetected error is to be less than 7.5 × 10-11, or approximately 1 in 13 300 000 000.
 
"
 
Unless we can produce some sort of mathematical proof that we meet the following requirement, then we should adopt comment 019. Otherwise the EC should rightly reject the standard on the grounds that it doesn't meet the baseline 802 requirements.
 
I don't know about others, but my experience with wireless systems tells me that a deep fading killing off 8 continuous fragments is way more likely that 1 in 5E14 (per octet as above).
 
So the objection that it is an 'unlikely' event, while valid in principle, fails if 'unlikely' is more likely that 1 in 5E14 and I suspect this is the case, although as usual, the devil may be in the details. Either way, I strongly suggest we accept comment 019 to be on the safe side.
 
DJ