Dell PowerSwitch S4820T Configuration Guide for the S4820T System 9.112.0P1 - Page 403

To test and display TDR results, use the following commands. 1 To test for cable faults on the TenGigabitEthernet cable. EXEC Privilege mode tdr-cable-test tengigabitethernet slot/port Between two ports, do not start the test on both ends of the cable. Enable the interface before starting the test. Enable the port to run the test or the test prints an error message. 2 Displays TDR test results. EXEC Privilege mode show tdr tengigabitethernet slot/port Configuring wavelength for 10-Gigabit SFP+ optics You can set the wavelength for tunable 10-Gigabit SFP+ optics using the wavelength command. To set the wavelength, follow these steps: • Enter the interface mode and set the wavelength. INTERFACE mode wavelength 1529.0 The wavelength range is from 1528.3 nm to 1568.77nm. • Verify configuration changes. INTERFACE mode show config Link Dampening Interface state changes occur when interfaces are administratively brought up or down or if an interface state changes. Every time an interface changes a state or flaps, routing protocols are notified of the status of the routes that are affected by the change in state. These protocols go through the momentous task of re-converging. Flapping; therefore, puts the status of entire network at risk of transient loops and black holes. Link dampening minimizes the risk created by flapping by imposing a penalty for each interface flap and decaying the penalty exponentially. After the penalty exceeds a certain threshold, the interface is put in an Error-Disabled state and for all practical purposes of routing, the interface is deemed to be "down." After the interface becomes stable and the penalty decays below a certain threshold, the interface comes up again and the routing protocols re-converge. Link dampening: • reduces processing on the CPUs by reducing excessive interface flapping. • improves network stability by penalizing misbehaving interfaces and redirecting traffic. • improves convergence times and stability throughout the network by isolating failures so that disturbances are not propagated. Interfaces 403