1. Should Parameterized QoS be Optional
Month 2000
doc.: IEEE /xxx
September 2002
Should Parameterized QoS be Optional
Author:
Matthew Sherman
AT&T Labs - Research
Date: September 11, 2002
Matthew Sherman, AT&T Labs
John Doe, His Company

2. Purpose Provide AT&T “view” of views on
September 2002
Purpose
Provide AT&T “view” of views on
Optionality of polled /parameterized QoS
Interoperability requirements
Provide possible insights on straw polls from 09/10/02
Matthew Sherman, AT&T Labs

3. Background Two Types of QoS Two types of Access used for QoS
September 2002
Background
Two Types of QoS
Parameterized - Requires TSPEC
Prioritized - Classification at upper layers
Two types of Access used for QoS
Contention (E-DCF)
Contention Free (HCF)
QoS and Access Types are orthogonal
Could mix and match in any way desired
One mapping of QoS/Access types seems preferred
Prioritized maps to Contention (E-DCF)
Parameterized maps to Contention Free (HCF)
No other mapping seems to be of interest
Matthew Sherman, AT&T Labs

4. Background (Continued)
September 2002
Background (Continued)
To interoperate a QSTA and QAP must support same type of “QoS”
Most discussion focuses on access aspects of QoS
With current implied mappings this translates to requirements concerning other aspects as well
What types of QoS should be supported in QAP and QSTA to guarantee interoperability?
Depends on definition for interoperability
Matthew Sherman, AT&T Labs

5. What does it mean to be interoperable?
September 2002
What does it mean to be interoperable?
Interoperability can occur on may levels
TGe is a QoS standard
Means we want to define interoperable QoS
DCF does not provide interoperable QoS
Depending on view point can define interoperable in different ways
Has implications for functionality required for TGe
Matthew Sherman, AT&T Labs

6. The Two Parts to a Standard
September 2002
The Two Parts to a Standard
Interface must be defined
For instance, without defined interface can’t properly convey QoS needs between different vendors products
Behavior may also be defined
Given a set of inputs a QSTA/QAP may be required to act in a certain manner
Eg. E-DCF scheduling behavior fully defined given access parameters
Need to define required (mandatory) interface and behavior such that interoperable QoS is achieved
Matthew Sherman, AT&T Labs

7. Factions in TGe Three factions in TGe
September 2002
Factions in TGe
Three factions in TGe
Data oriented
AV oriented
Carrier / Infrastructure oriented
Each faction has different perception of interoperability needs
Matthew Sherman, AT&T Labs

8. Interoperability Arguments (Data)
September 2002
Interoperability Arguments (Data)
Don’t need hard core QoS ever
Too complex anyway
Differentiated service is enough
Have lowest level of QoS everywhere
Usually good enough
Can always interoperate
Make parameterized QoS optional at both ends
Prioritized QoS mandatory at both ends
Matthew Sherman, AT&T Labs

9. Interoperability Arguments (Carrier / Infrastructure)
September 2002
Interoperability Arguments (Carrier / Infrastructure)
Carrier specifies Access Point
Can require options be used in all their AP’s
Services not available outside their network
Or differentiated as inferior
Want devices (QSTA) which provide a “service” over carrier’s network to use carriers QoS
Otherwise can’t make QoS Guarantees
Parameterized QoS is easiest in QSTA
STA must respond to poll
STA must generate TSPEC (could be by rote)
Make prioritized mandatory everywhere
Make parameterized mandatory in STA
AT&T’s Preference
Matthew Sherman, AT&T Labs

10. Interoperability Arguments (AV / IP Phone)
September 2002
Interoperability Arguments (AV / IP Phone)
Mostly make Stations, not APs
Need their QoS to run in presence of APs
Mostly want parameterized / polled access
If not supported by AP, can’t run their QoS
Make prioritized mandatory everywhere
Make parameterized mandatory in STA
Matthew Sherman, AT&T Labs

11. One 802.11 Phone Vendor’s Example
September 2002
One Phone Vendor’s Example
Uses DCF for Phone
Wanted PCF
Could not find PCF AP vendor
PCF was optional
Don’t trust AP vendors to build Polling in if optional
They didn’t the first time
Matthew Sherman, AT&T Labs

12. Poll Results Fast Track Alternative QoS Proposal (Intel / Sharp)
September 2002
Poll Results
Fast Track
Base 67%
+ Distributed Admissions 70%
+ Time based TSPEC 66%
Optional AP Polling 37%
Opt. Poll + Dist. Admin 40%
Alternative QoS Proposal (Intel / Sharp)
Base 46%
+ Flow Tags 36%
Matthew Sherman, AT&T Labs

13. September 2002
Observations
Intel / Sharp proposal did not establish Parameterized QoS / polling as mandatory
Fast Track proposals with mandatory polling in AP all had high approvals
Fast Track without polling mandatory did as bad as Intel / Sharp proposal
Any way forward must have parameterized QoS mandatory in AP
Makes sense since majority of participants provide STAs rather than APs
Matthew Sherman, AT&T Labs