Administrator Guide

● QSFP port 0 is connected to a QSA with SFP+ optical cables plugged in.
● QSFP port 4 is connected to a QSA with SFP optical cables plugged in.
● QSFP port 8 in fanned-out mode is plugged in with QSFP optical cables.
● QSFP port 12 in 40 G mode is plugged in with QSFP optical cables.
For these configurations, the following examples show the command output that the show interfaces
tengigbitethernet transceiver, show interfaces tengigbitethernet, and show inventory media
commands displays:
NOTE: In the following show interfaces tengigbitethernet commands, the ports 1,2, and 3 are inactive and no
physical SFP or SFP+ connection actually exists on these ports. However, Dell Networking OS still perceives these ports as
valid and the output shows that pluggable media (optical cables) is inserted into these ports. This is a software limitation for
this release.
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.
Important Points to Remember
● Link dampening is not supported on VLAN interfaces.
● Link dampening is disabled when the interface is configured for port monitoring.
● You can apply link dampening to Layer 2 and Layer 3 interfaces.
● You can configure link dampening on individual interfaces in a LAG.
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Interfaces