1. EDCF Traffic Categories and Access Parameters
September 2001
EDCF Traffic Categories and Access Parameters
Menzo Wentink
Intersil Corp.
Menzo Wentink, Intersil

2. Status 8 TCs are currently defined
September 2001
Status
8 TCs are currently defined
but less than 8 queues may be implemented
this requires mappings between TCs and queues, to determine both the access parameters that the queue will use and the traffic that is routed to it
8 EDCF access categories seems not very practical
the mappings between access parameters and queues are currently ambiguous
this was noted earlier by Sunghyun Choi
and contradict each other
this may potentially lead to unpredictable behavior
especially the choice of access parameters is a problem
Menzo Wentink, Intersil

3. Proposed Solution (1) the number of Traffic Categories is reduced to 4
September 2001
Proposed Solution (1)
the number of Traffic Categories is reduced to 4
the QoS beacon carries 4 sets of access parameters
4 queues are normative
when certain types of traffic are never present, the corresponding queue needs not to be implemented
each TC maps one-on-one with a queue
Menzo Wentink, Intersil

4. September 2001
Proposed Solution (2)
The 802.1D Traffic Type and User Priority are mapped as:
802.1D
Traffic Type
User Priority
802.11e
Traffic Category
bk, sp
1, 2 1
be, ee
0, 3
vi, cl
4, 5 2
vo, nc
6, 7 3
bk = background
sp = spare
be = best effort
ee = excellent effort
vi = video
cl = controlled load
vo = voice
nc = network control
Menzo Wentink, Intersil

5. September 2001
Proposed Solution (3)
the MAC headers of QoS Data frames could signal either the User Priority (0-7) or the Traffic Class (0-3)
signaling the User Priority ensures end-to-end compatibility with 802.1D
signaling the Traffic Category frees up 4 tags, which could potentially be used for other purposes or omitted from the header
The choice depends on the relative importance of end-to-end 802.1D compatibility
Menzo Wentink, Intersil