Manualshelf

Administrator Guide

ManualsBrandsDell ManualsAccess PlatformsFN IO Module
431432433434435436437438439440
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.
Layer 2 Flow Control Using Ethernet
Pause Frames
Ethernet pause frames allow for a temporary stop in data transmission.
A situation may arise where a sending device may transmit data faster than a destination device can accept it.
The destination sends a pause frame back to the source, stopping the sender’s transmission for a period of
time.
Interfaces 436