Administrator Guide

NOTE: You can use the QSA adaptor to establish connectivity between a high-density 100 Gigabit platform and a
relatively lower-end 1 Gigabit switch or a server. The QSA acts as an interface between the QSFP28 ports (that support
100 Gigabit speeds) and SPF optics with a maximum speed of 1 Gigabit per second. Depending on the type of optics you
plug into the QSA connected to a 100 Gigabit port, the system automatically detects the supported speed of the optics
and sets the interface speed accordingly. For example, if you plug in optics that support 40 Gigabit speeds, the speed of
the interface is set to 40G. Similarly, if you plug in optics that support 1G speed, the speed of the interface is set to 1G.
Important Points to Remember
• Before using the QSA to convert a 40 Gigabit Ethernet port to a 10 Gigabit SFP or SFP+ port, enable 40 G to 4*10 fan-out mode on
the device.
• When you insert a QSA into a 40 Gigabit port, you can use only the first 10 Gigabit port in the fan-out mode to plug-in SFP or SFP+
cables. The remaining three 10 Gigabit ports are perceived to be in Link Down state and are unusable.
• You cannot use QSFP Optical cables on the same port where QSA is used.
• When you remove the QSA module alone from a 40 Gigabit port, without connecting any SFP or SFP+ cables; Dell Networking OS
does not generate any event. However, when you remove a QSA module that has SFP or SFP+ optical cables plugged in, Dell
Networking OS generates an SFP or SFP+ Removed event.
Example Scenarios
Consider the following scenarios:
• 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
Interfaces
421