1. Overloading More bit Date: 2006-05-15 Authors: May 2006 Month Year
doc.: IEEE yy/xxxxr0
May 2006
Overloading More bit
Date:
Authors:
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Kumar
John Doe, Some Company

2. More bit in base std Original Intent Implementation
Month Year
doc.: IEEE yy/xxxxr0
May 2006
More bit in base std
Original Intent
to assist PS clients to manage their wake-up time efficiently without causing significant delay in data packet delivery
Implementation
Generally implemented in firmware; look at a (hardware) queue 6-12 packets deep to see if there are any “more” packets for the STA in question
Kumar
John Doe, Some Company

3. Month Year
doc.: IEEE yy/xxxxr0
May 2006
Overload More bit in 11r
Intends to reduce packet loss during Fast BSS by flipping the more bit to 1 as an indication to the STA that it might not be a good time to transition over since the current AP has “more” packets for it.
The claim is that its important for TCP traffic because a single packet loss at layer 3 will shrink the TCP window and hence reduce throughput momentarily.
Thus, in effect, the feature aims at avoiding “throughput bumps” during a Fast BSS r
Kumar
John Doe, Some Company

4. When does this come into play?
Month Year
doc.: IEEE yy/xxxxr0
May 2006
When does this come into play?
Within the Fast BSS time-frame ~50ms period
The scheme may work if all conditions are met:
there is a constant flow of packets for a STA ( meaning there is hardly any jitter in the DS )
the AP can look deep enough to really predict that packets are impending for the STA
the STA is not moving fast enough that it can afford to stick around with the old AP until the more-bit gets flipped to 0.
Kumar
John Doe, Some Company

5. Month Year
doc.: IEEE yy/xxxxr0
May 2006
Does this really help ?
Whenever this scheme works, it may be helpful for TCP applications like FTP and HTTP; does not help in isochronous traffic such as VoIP.
For a constant TCP stream for say FTP, you are going to loose packets anyway when you transition, because the more bit will always be 1 !
For HTTP ( bursty traffic ), it helps only if your burst coincides with your FBT !
Kumar
John Doe, Some Company

6. Month Year
doc.: IEEE yy/xxxxr0
May 2006
Is it implementable?
Since the scheme aims at increasing throughput by looking at packets coming from the DS, it needs to look far enough into various network elements in the DS to know when to flip the bit to 1 and when to flip it back to 0 ?
How deep should you look ? It is not efficient to look beyond ?
Implementation is limited by what can be done at the firmware level.
We are better off designing efficient layer 3 cut-over mechanisms in the DS (out of TGr scope ).
Why have something in standard that is not implementable !
Kumar
John Doe, Some Company

7. Month Year
doc.: IEEE yy/xxxxr0
May 2006
Motion
Instruct the editor to accept proposed resolution from the commenter for comment #208 and #1431, as documented in r-d2-comments.xls
By:
Second :
Result: Yes - ; No - ; Abstain -
Kumar
John Doe, Some Company