Users Guide

You can use QSFP optical cables (without a QSA) to split a 40 Gigabit port on a switch or a server into four 10
Gigabit ports. To split the ports, enable the fan-out mode.
Similarly, you can enable the fan-out mode to configure the QSFP port on a device to act as an SFP or SFP+
port. As the QSA enables a QSFP or QSFP+ port to be used as an SFP or SFP+ port, Dell Networking OS does
not immediately detect the QSA after you insert it into a QSFP port cage.
After you insert an SFP or SFP+ cable into a QSA connected to a 40 Gigabit port, Dell Networking OS assumes
that all the four fanned-out 10 Gigabit ports have plugged-in SFP or SFP+ optical cables. However, the link UP
event happens only for the first 10 Gigabit port and you can use only that port for data transfer. As a result,
only the first fanned-out port is identified as the active 10 Gigabit port with a speed of 10G or 1G depending
on whether you insert an SFP+ or SFP cable respectively.
NOTE: Although it is possible to configure the remaining three 10 Gigabit ports, the Link UP event does
not occur for these ports leaving the lanes unusable. Dell Networking OS perceives these ports to be in a
Link Down state. You must not try to use these remaining three 10 Gigabit ports for actual data transfer or
for any other related configurations.
NOTE: You cannot enable 1G speed on any port with auto-negotiation enabled. As a result, when you
connect to a device using SFP, the link does not come up if auto-negotiation is enabled. To use a port in
1G speed, disable auto-negotiation. This limitation applies only when you convert QSFP to SFP using the
QSA. This constraint does not apply for QSFP to SFP+ conversions using the QSA.
Important Points to Remember
• Starting from Dell OS 9.7(0.0), as part of dynamic fan-out support, only 96 ports can be split into 10G
mode. Remaining eight ports stay in 40G. For more information, see
Fanning out 40G Ports Dynamically.
• 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.
• You can use the QSA on any of the ports.
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.
Interfaces 437