doc.: IEEE wpp Submission September 2004 B. Mandeville, Iometrix A First Stab at Metrics Bob Mandeville

doc.: IEEE wpp Submission September 2004 B. Mandeville, Iometrix Introduction We present a first cut of a list of metrics believed to be important for wireless performance This presentation is AP-centric –Does not mean there are not important client- centric metrics as well! Input welcome! –Please help with identifying additional metrics

doc.: IEEE wpp Submission September 2004 B. Mandeville, Iometrix Considerations We need to be able to reference well- defined metrics for wireless when we build test definitions and test cases In defining metrics it is important to focus on the wireless aspects of the metrics –we need to concentrate on what is special about wireless metrics (examples to follow)

doc.: IEEE wpp Submission September 2004 B. Mandeville, Iometrix Initial List of Wireless Performance Metrics Maximum Forwarding Rate FWMOL (Fwd rate at max offered load) Frame Loss, Frame Loss Rate Latency Jitter Association Capacity, Association Rate Rate versus Range

doc.: IEEE wpp Submission September 2004 B. Mandeville, Iometrix RFC 2285 Considerations RFCs 2285 and 2889 define terms and methods for testing wired switched Ethernet performance Basic definitions contain useful content for wireless metric definitions but we cannot take those definitions and directly apply them to wireless –How do traffic orientations and configurations translate to ? –Need to specify protocol modifiers Could be a long list, starting with RTS/CTS, fragmentation, security modes… Measure metrics under optimum signal conditions –Conducted signals - DUT can do no better than this!

doc.: IEEE wpp Submission September 2004 B. Mandeville, Iometrix First shot at defining wireless forwarding rate Definition of wireless forwarding rate should include a clear treatment of at least the following aspects (3 slides): The metric (wireless forwarding rate) must indicate what interfaces, wireless and wired, are the source and destination of the measurement traffic configuration:.11 to.3.11 to to.3 to.11 –Could call this aspect of the metric ‘traffic configuration’ –It is specific to –RFC 2285 only defines traffic orientation (unidirectional, bidirectional) and distribution (partial mesh, full mesh)

doc.: IEEE wpp Submission September 2004 B. Mandeville, Iometrix First shot considerations… Need to distinguish between the inherent fwd rate capabilities of a device and the possibly reduced capabilities in a real wireless environment Need to specify what protocol exchanges must take place before the measurement of the metric can take place –association/authentication rates and capacities are separate metrics

doc.: IEEE wpp Submission September 2004 B. Mandeville, Iometrix More considerations Need to define what address sequencing is to be used when measuring wireless forwarding rate Need to define traffic pattern including burst. –RFC 2285 definition for burst does not apply (minimum ifg) –Perhaps to be defined outside of forwarding rate definition Need to discuss list of modifiers that may be applied to forwarding rate measurement: RTS/CTS, fragmentation

doc.: IEEE wpp Submission September 2004 B. Mandeville, Iometrix Carry-over definitions RFC 2285 definitions of Intended Load and Offered Load (developed with half-duplex Ethernet in mind) are very relevant for contentious shared medium RFC 2285 distinctions between ‘maximum forwarding rate’ and ‘forwarding rate at maximum offered load’ are relevant to

doc.: IEEE wpp Submission September 2004 B. Mandeville, Iometrix Going forward… Does group think the initial list of performance metrics is of value? Does group think the considerations for wireless forwarding rate metric enumerated here form basis for going forward with work further on the definition Is there something missing? Is there another better approach? Again: definition of a wireless performance metric is not a test definition but supplies a necessary component for wireless test definitions