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Hi Graham, I get roughly the same numbers for "results" (slide 8) but I do not agree with your interpretation. There is a problem when two STAs try to use the same MAC address. That probability is very
remote. Even if, as you assume, 80,000 STAs associating (note, I believe the record for simultaneous associations in a single ESS is closer to 30,000 but let's plan for the future) and each one associates 3 times per day that does not mean there will be 15.75
duplicates per day because these 80,000 STAs are not running through their random MACs simultaneously. The probability of 2 STAs using the same MAC at the same time if there are 80,000 STAs associating is still 0.000045. It's not 1 (which 15 duplicates per
day would imply). And I agree with Mike. We can use all 46 bits for randomization. Nobody's doing the SLAP for 802.11 networks. regards, Dan. -- "the object of life is not to be on the side of the majority, but to escape finding oneself in the ranks of the insane." – Marcus Aurelius On 5/20/24, 7:22 AM, "G Smith" <gsmith@xxxxxxxxxxxxxxxxxxx> wrote: Hi TGbh’s, At the Interim last week we discussed CID 3085 which proposed to define IRM as follows
: " A MAC address selected randomly from among the Administratively Assigned local identifiers specified in IEEE Std 802 and used by a non-access point
(non-AP) station (STA) to identify itself to a network." Using the AA designation means that the IRM would comprise 44 random bits as against 46 bits if we kept to the present “constructed from the locally
administered address space”. I had previously uploaded, but never presented, 23/2148r0 which looked at the theoretical probabilities of IRM duplicates for ESSs up to 80,000 stations
using IRMs of 46 random bits. I have now posted r1 where I have added the results for IRMs of 44 random bits. https://mentor.ieee.org/802.11/dcn/23/11-23-2148-01-00bh-probability-of-irm-duplicates.pptx The results are: For a busy ESS (network), with each STA associating 3 x per day, storing a high number of IRMs (80,000)
For 46 random bits:
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Each AP (40) in ESS has a duplicate every 2.54 days
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Each STA only experiences a duplicate every 14 years. (i.e., Action frame exchange to get new IRM is a small overhead) Notes: Assumed 2000 STAs per AP For S1G (8000 STAs per AP), each AP has 1.57 duplicates per day. For 44 random bits:
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Each AP in ESS has a duplicate 1.57 times per day (i.e., 4 times more frequently)
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Each STA experiences a duplicate every 3.5 years. Note: For S1G (8000 STAs per AP), each AP has 6.3 duplicates per day I do not intend to ask Mark for time to present this as it would probably take up a lot of valuable time. I have included all the formulas and derivations I used, so those interested can check my analysis and results,
and of course, I welcome comments. The results are what matters as I have provided above. Of course if anyone feels that my assumptions of the maximum size (80,000) ESS should be different, or each STA should on average associate more (or less) than 3x a
day, please let me know and I will run the numbers accordingly. I leave it to the group to decide if the effect of reducing the random bits from 46 to 44 is significant enough that we could use it as a reason to stick with the “locally administered address space”, and not change
to “selected randomly from among the Administratively Assigned local identifiers specified in IEEE Std 802.”? Thanks Graham To unsubscribe from the STDS-802-11-TGBH list, click the following link:
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