Evaluation of RR over EDCF Month 2000 doc.: IEEE 802.11-00/xxx May 2002 Evaluation of RR over EDCF Author: Matthew Sherman AT&T Labs - Research 180 Park Avenue Florham Park, NJ 07932 973-236-6925 mjsherman@att.com Date: May 13, 2002 Matthew Sherman, AT&T Labs - Research John Doe, His Company

Month 2000 doc.: IEEE 802.11-00/xxx May 2002 Purpose of Document Report on feasibility study conducted by AT&T concerning replacing CCI with RR over EDCF Matthew Sherman, AT&T Labs - Research John Doe, His Company

Background Numerous suggestions to replace CC/RR with RR over EDCF Month 2000 doc.: IEEE 802.11-00/xxx May 2002 Background Numerous suggestions to replace CC/RR with RR over EDCF Large simulation base for EDCF For example 01/019, 01/133, 01/409, 01/525, 01/613 Large simulation base for CC/RR For example 01/571r0, 02/223r1, 02/303, 02/304 No set of simulations that combine both EDCF and CC/RR No evidence that RR over EDCF would or would not effective Matthew Sherman, AT&T Labs - Research John Doe, His Company

MAC Model Started with code from 02/304 Added EDCF parameters May 2002 MAC Model Started with code from 02/304 AT&T date stamp 4/7/02 Added EDCF parameters Included Persistence Factor as nonstandard option Defaults to standard DCF settings for 802.11b Only supports one Traffic Category (TC) per station All applications on station must use same TC Not an issue for simulations conducted Added RR over EDCF option to PCF Parameters If set in AP, no CC will be sent If set in STA, may send either during CCI or CP Coded so that AP will always accept RR during CP Decided to respond with Ack rather than CC during CP Matthew Sherman, AT&T Labs - Research

New MAC Parameters Added DCF RR Option Added EDCF Parameters Month 2000 doc.: IEEE 802.11-00/xxx May 2002 New MAC Parameters Added DCF RR Option Added EDCF Parameters Matthew Sherman, AT&T Labs - Research John Doe, His Company

Simulation Model / Scenarios May 2002 Simulation Model / Scenarios Started with scenarios in 02/304 Uncontrolled DCF Sources (UDS) modeled as Video traffic with standard DCF parameters Added 2 new scenarios Baseline RR over EDCF (No UDS) All PCF stations use RR over EDCF AP configured for no CCI RR over EDCF with one UDS Same UDS parameters as in 02/304 Used MAC code with AT&T date stamp 5/8/02 Used EDCF (Enhanced Contention) parameters shown on slide 5 for PCF stations RR only EDCF traffic When present UDS uses DCF default parameters Matthew Sherman, AT&T Labs - Research

May 2002 Plots Collected Full set of plots given in 02/223r1 provided here for comparison Include CC/RR performance plots for benchmarking Many plots not very meaningful for UDS Particularly true for WLAN global statistics May even be misleading since interactions between layers make MAC performance difficult to interpret Key results will prove to be application delays “Video” at end of scenario name in legend indicates UDS link is active Matthew Sherman, AT&T Labs - Research

May 2002 Data Plots Matthew Sherman, AT&T Labs - Research

Throughput (moving average of 240) May 2002 Throughput (moving average of 240) No UDS link One UDS link Matthew Sherman, AT&T Labs - Research

Load (moving average of 240) May 2002 Load (moving average of 240) No UDS link One UDS link Matthew Sherman, AT&T Labs - Research

Data Dropped (Note difference in Scale) May 2002 Data Dropped (Note difference in Scale) No UDS link One UDS link Matthew Sherman, AT&T Labs - Research

Delay (global) (Note difference in Scale) May 2002 Delay (global) (Note difference in Scale) No UDS link One UDS link Matthew Sherman, AT&T Labs - Research

Control Traffic Received at AP May 2002 Control Traffic Received at AP No UDS link One UDS link Matthew Sherman, AT&T Labs - Research

Control Traffic sent by AP May 2002 Control Traffic sent by AP No UDS link One UDS link Matthew Sherman, AT&T Labs - Research

Media Access Delay at Voice STA 1 May 2002 Media Access Delay at Voice STA 1 No UDS link One UDS link Matthew Sherman, AT&T Labs - Research

Media Access Delay at Voice STA #19 May 2002 Media Access Delay at Voice STA #19 No UDS link One UDS link Matthew Sherman, AT&T Labs - Research

Voice Throughput per STA May 2002 Voice Throughput per STA No UDS link One UDS link Matthew Sherman, AT&T Labs - Research

FTP Traffic served (moving average of 240) May 2002 FTP Traffic served (moving average of 240) No UDS link One UDS link Matthew Sherman, AT&T Labs - Research

HTTP Traffic served (moving average of 240) May 2002 HTTP Traffic served (moving average of 240) No UDS link One UDS link Matthew Sherman, AT&T Labs - Research

FTP download time (moving average of 10) May 2002 FTP download time (moving average of 10) No UDS link One UDS link Matthew Sherman, AT&T Labs - Research

HTTP Page Response Time (moving average of 10) May 2002 HTTP Page Response Time (moving average of 10) No UDS link One UDS link Matthew Sherman, AT&T Labs - Research

Data Analysis - Plots Key differentiators are upload / download times May 2002 Data Analysis - Plots Key differentiators are upload / download times As with alternatives suggested in 02/223r1, CC/RR maintains substantial voice delay advantage even without UDS Since FTP traffic dominates, FTP upload / download times most important RR over EDCF comparable to CC/RR without UDS RR over EDCF highly degraded with UDS UDS has no obvious effect on CC/RR HTTP traffic suffers for UDS with RR over EDCF as well Given existing plots, summary statistics seem unnecessary at this time Matthew Sherman, AT&T Labs - Research

May 2002 Conclusions Uncontrolled DCF Sources (UDS) significantly degrade performance of RR over EDCF CC/RR is not significantly degraded by UDS CC/RR voice performance is substantially better than for RR over EDCF Typically 2:1 Uncontrolled DCF sources are an important issue for Managed LANs AT&T implementation of protocol shows that CC/RR complexity is not an issue Don’t need RR over EDCF to save on complexity Managed WLANS are critical target market area Cannot afford to adopt protocol such as RR over EDCF which strongly degrades with UDS Matthew Sherman, AT&T Labs - Research