1. Implementation for Intra-AC Differentiated Services
9/10/2018May 2008
November 2007
doc.: IEEE /2752r1
Implementation for Intra-AC Differentiated Services
Date:
Authors:
Jun Li, Thomson Inc..
Peter Ecclesine, Cisco Systems

2. 9/10/2018May 2008
November 2007
doc.: IEEE /2752r1
Abstract
One of the goals of aa is to enable MAC layer adaptation based on differentiated frames in a video stream. This requires an intra-AC differentiated service, which is not supported in current This proposal discusses the implementation on intra-AC DiffServ.
Jun Li, Thomson Inc..
Peter Ecclesine, Cisco Systems

3. Why we need intra-AC DiffServ?
Why we need intra-AC DiffServ?
Two of objectives in aa PAR related to Intra-AC DiffServ
Graceful degradation of audio video streams when there is insufficient channel capacity, by enabling packet discarding without any requirement for deep packet inspection.
Intra-Access Category prioritization of transport streams by modifying EDCA timing and parameter selection without any requirement for deep packet inspection.
Different frames have different importance in a video transport stream, e.g.,
A MAC frame may contain
SVC base layer or enhance layer;
I,P,B frames in MPEG-2 or H.264
Region of interest based encoding
Jun Li, Thomson Inc..

4.
The Proposal
Intra-AC differentiated service (IACDS): A service that allows MAC layer intra-AC prioritization of transport streams and selective frame discarding when there is insufficient channel capacity without any requirement for deep packet inspection.
enables modifying the EDCA timing and parameter selection for frames belonging to the same AC for intra-AC prioritization
enables frame discarding for graceful degradation of audio video streams when there is insufficient channel capacity.
When a non-AP STA sends a data frame to the AP,
The source non-AP STA can classify the frames into different intra-AC priority and assigns their DEIs.
Intra-AC differentiated service tag (IACDST) is carried in the frame
2 bits for intra-AC priority (IACP), and 2 bits for drop precedence or Drop Eligible Indicator (DEI)
A non-AP STA may request the AP to classify the frames destined to it.
Using ADDTS Request/Response or new action frames
Jun Li, Thomson Inc..

5. Intra-AC differentiated service tag
Intra-AC differentiated service tag
Intra-AC differentiated service tag (IACDST)
Carried in a frame from a non-AP STA to an AP when EDCA is used as access policy (TID = 0-7)
No extra signaling for EDCA
Possible fields to carry IACDST tag
For n frame with HT Control field, IACDST may be carried in the HT control field or
IACDST may be carried in the QoS control field
B0B1 00
No action 01
low 10
high 11
resv
B2B3 00
default 01
alt1 10
alt2 11
resv B0 B1 B2 B3
Drop
Precedence
Intra-AC Priority
Jun Li, Thomson Inc..

6. Intra-AC Traffic Classifier Element
Intra-AC Traffic Classifier Element
Intra-AC Traffic Classifier (ITCLAS) IE can be carried in ADDTS Request/Response or new stream classification action frames for non-AP STA to request the AP to classify the frame for Intra-AC diffserv
Intra-AC Diffserv Info
Frame Classifier
Element ID
Length
ITCLAS ID 2
Octets 1 1 1 B0 B2 B3 B4 B5 B6 B7
B15
Intra-AC Priority
Drop Precedence
User Priority
Reserved
Bits 3 2 2 9
Jun Li, Thomson Inc..

7. Intra-AC Traffic Classifier Processing Element
Intra-AC Traffic Classifier Processing Element
Present in the stream classification Request and Response frames if there are multiple ITCLASs associated with the same Intra-AC Diffserv Info. It indicates how an MSDU received from higher layers should be processed by the multiple classifiers.
Intra-AC Diffserv Info
Element ID
Length
Processing 1
Octets 1 1 2
Processing
Incoming MSDU’s higher layer parameters have to match to the parameters in all the associated ITCLAS elements. 1
Incoming MSDU’s higher layer parameters have to match to at least one of the associated ITCLAS elements. 2
Incoming MSDUs that do not belong to any other intra-AC priority are classified to this intra-AC priority for which this ITCLAS Processing element is used. In this case, there shall not be any associated ITCLAS elements.
3-255
Reserved
Jun Li, Thomson Inc..

8. Intra-AC EDCA Parameter Set Element
Intra-AC EDCA Parameter Set Element
Intra-AC EDCA Parameter Set element is used by the AP to establish or change EDCA parameters for an intra-AC priority.
In beacons and probe responses
The most recent EDCA parameter set element received by a non-AP STA is used.
If the intra-AC EDCA parameters are not set, use the default EDCA parameters of the corresponding AC
Intra-AC EDCA Parameter Set
Update Count
# of Intra-AC EDCA Parameter records
Intra-AC EDCA Parameter record 1
Intra-AC EDCA Parameter record 2
Element ID
Length 1 1 1
Octets 1 1 1
ECWmin/
ECWmax
UP/Intra-AC Priority
AIFSN
TXOP Limit 2
Octets 1 1 1
Jun Li, Thomson Inc..

9. TID/Intra-AC Priority/DEI
An Example
From non-AP STA to AP
TID/Intra-AC Priority/DEI
Map to 802.1AVB
Forward based on TID/Intra-AC Priority/DEI
Jun Li, Thomson Inc..

10. An Application Example
An Application Example
From AP to Non-AP
Request to classify
Response to classify
Jun Li, Thomson Inc..