1. Cleaning Up MAC/PHY Interface Timing
November 2001
Cleaning Up MAC/PHY Interface Timing
Michael Fischer
Intersil Corporation Medical Drive San Antonio, TX voice: fax:
Michael Fischer, Intersil

2. November 2001
Introduction
In of D1.3 there is an open issue identified, as follows:
OPEN ISSUE: It appears that the current fragmentation rules are unnecessarily restrictive, in particular that all fragment sizes must be equal. Fragmentation should not be arbitrary, and fragments other than the last should be of even lengths, but it may be appropriate to relax some of the legacy restrictions.
This submission proposes to close this open issue in the manner suggested therein:
Permit fragment sizes to vary in fragmented data and management type frames directed to ESTAs (including EAPs) with the following restrictions:
The frame body of all but the final fragment of any MSDU must contain an even number of octets.
No refragmentation is permitted. Any retries which may be necessary involve retransmission of the same fragment as was originally transmitted.
The fragment size rules for data and management type frames directed to STAs remain unchanged to avoid backward compatibility problems.
Michael Fischer, Intersil

3. Normative Text Changes (1)
November 2001
Normative Text Changes (1)
Change the second paragraph of 9.4 as shown:
For MPDUs sent in a non-QoS BSS, the length of a fragment MPDU shall be an equal number of octets for all fragments except the last, which may be smaller. For MPDUs sent in a QBSS, there is no requirement for equality of fragment lengths for fragment MPDUs directed to QSTAs (including the QAP). The length of (a) every fragment MPDU shall (always) be an even number of octets, except for the last fragment of an MSDU or MMPDU, which may be either an even or an odd number of octets. The length of a fragment shall never be larger than (a)dot11FragmentationThreshold unless WEP is invoked for the MPDU. If WEP is active for the MPDU, then the MPDU shall be expanded by IV and ICV (see 8.2.5); this may result in a fragment larger than (a)dot11FragmentationThreshold .
Michael Fischer, Intersil

4. Normative Text Changes (2)
November 2001
Normative Text Changes (2)
Change the third paragraph of 9.4 as shown:
When (data) an MSDU or MMPDU is to be transmitted by a (non-QoS) STA, the number of octets in the fragment (before WEP processing) shall be determined by (a)dot11FragmentationThreshold and the number of octets in the MPDU or MMPDU that have yet to be assigned to a fragment at the instant the fragment is constructed for the first time. When an MSDU or MMPDU is to be transmitted to a QSTA associated in a QBSS or the QAP of a QBSS, the value of dot11FragmentationThreshold only needs to be considered as an upper bound as described in the previous paragraph. Once a fragment is transmitted for the first time, its frame body content and length shall be fixed until it is successfully delivered to the immediate receiving (Q)STA. A (Q)STA shall be capable of receiving fragments of arbitrary length.
Michael Fischer, Intersil

5. November 2001
Motion
Move to empower the TGe editor to incorporate the changes to 9.4 as given on slides 3 and 4 of 01/626r0 into the TGe draft.
Michael Fischer, Intersil