application-model web

Sets the characteristics that affect the behavior of the web application model, which optimizes web transactions on your network.

application-model web
 
          {  ( delay { half-life <hlife> } ) |
 
             ( hrtt { half-life <hlife> |
 
                      metric-contribution <metric> |
 
                      threshold <threshold>
 
                    }
 
             ) |
 
             ( loss { descent-rate <meas> <target-loss> } |
 
                        half-life <hlife> |
 
                    }
 
             )
 
          }
 

 
no application-model web
 
no application-model web delay [ half-life ]
 
no application-model web hrtt  [ half-life | metric-contribution | threshold ]
 
no application-model web loss  [ descent-rate | half-life ]
 

 

• hlife--(exact meaning depends upon which of the following keywords is used)
• delay half-life: smoothing factor of average delay; range: 0 through 15000 (default 150)
• hrtt half-life: smoothing factor of average handshake round trip time (hrtt); range: 0 through 15000 (default 50)
• loss half-life: smoothing factor of measured loss; range: 0 through 15000 (default 300)
• mcontr--range: 0 through 5000 (default 915)
• meas--internal parameter - do not change; range: 0 through 5000 (default 250)
• target-loss--internal parameter - do not change; range: 1 through 100 (default 1)

Must be in engine or policy configuration mode (config-engine or config-engine-policy), which requires privileged-level access.

Available for use multiple times in the configuration.

Use the application-model web command to change the default behavior of this model to suit the particular needs of your network. You may create as many variants as you wish by assigning each to a specific decision policy. See Details on Application Models in Chapter 6: Decision Policies and Application Models of the CNA Basic Monitoring Guide.

NOTE: The web application model is designed for TCP and user traffic test (UTT) measurements (i.e., single pixel gif). You can use ICMP and traceprobe measurements with the web model; however, the enterprise model has been designed to use the separate delay and loss signals from these measurement types. We recommend the web model if the majority of your measurements are TCP or UTT, and the enterprise model if you primarily use ICMP or traceprobe.

The following keywords control the major components of the web application model:

• delay - determines how the moving average of delay is calculated. The half-life parameter controls the smoothness of the delay moving average: A high value results in smaller changes in the calculated average delay because the delay contribution of past measurements will be greater than when half-life is set low. This parameter will not affect decision-maker’s calculations, but is used only by the reporting module.
• hrtt - determines how handshake round trip time will influence decision-maker’s calculations. The metric-contribution affects the weighting of the measured hrtt. Its value determines the mid-point of a curve that tells decision-maker how strictly it should regard measured hrtt in its decisions. A higher number for this value will place greater importance on it (i.e., an application is considered to be impacted more by longer handshake round trip times).
• loss descent-rate - this is an internal parameter, do not change it
• loss half-life - controls the smoothing factor of measured loss. A high value results in a smaller contribution of past loss events. This parameter will not affect decision-maker’s calculations, and is used only by the reporting module.

Use the no form of the command to revert to the default settings.