Rear Cards in a QFX3008-I Interconnect Device
The rear cards provide the intermediate stage of switch fabric functionality in a QFX3008-I Interconnect Device. See Figure 1.
A QFX3008-I Interconnect Device has eight rear cards. In the QFX3008-I Interconnect Device, all eight rear cards are simultaneously active when the device is operational. All rear cards are fully connected to all installed 16-port QSFP+ front cards. If a single rear card fails, the input/output traffic for that card is load-balanced among the remaining rear cards, providing graceful degradation in switching performance. The impact of a rear card failure on the performance of a QFX3008-I Interconnect Device varies based on the number of 16-port QSFP+ front cards installed in the device and the traffic mix flowing through them.

The rear cards are installed at the rear of the chassis in the
slots labeled 0 through 7. See Slot Numbering for a QFX3008-I Interconnect Device.
The rear cards are hot-insertable and hot-removable field-replaceable units (FRUs). However, you must take the rear cards offline before removing them. See Taking the Rear Card Offline in a QFX3008-I Interconnect Device.
The rear cards provide these functions:
Provide data path connectivity for the QFabric (switch data between Node devices)
The rear cards have these components:
Rear card LEDs—Indicate system status. See Rear Card LEDs on a QFX3008-I Interconnect Device.
Ejector levers—Used for installing and removing the rear card.
