Juniper QFX5220, Hardware Manual, Page: 89 / 247

Cable Specifications for QSFP+ and QSFP28 Transceivers
The 40-Gigabit Ethernet QSFP+ and 100-Gigabit Ethernet QSFP28 transceivers that are used in QFX
Series switches use 12-ribbon multimode fiber crossover cables with female MPO/UPC connectors. The
fiber can be either OM3 or OM4. These cables are not sold by Juniper Networks.
CAUTION: To maintain agency approvals, use only a properly constructed, shielded
cable.
TIP: Ensure that you order cables with the correct polarity. Vendors refer to these crossover cables
as key up to key up, latch up to latch up, Type B, or Method B. If you are using patch panels between
two QSFP+ or QSFP28 transceivers, ensure that the proper polarity is maintained through the
cable plant.
Table 31 on page 92 describes the signals on each fiber. Table 32 on page 93 shows the pin-to-pin
connections for proper polarity.
Table 31: QSFP+ and QSFP28 Optical Module Receptacle Pinouts
Signal Fiber
Tx0 (Transmit) 1
Tx1 (Transmit) 2
Tx2 (Transmit) 3
Tx3 (Transmit) 4
Unused 5
Unused 6
Unused 7
Unused 8
Rx3 (Receive) 9
Rx2 (Receive) 10
92