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 socket 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 1 describes the signals on each fiber. Table 2 shows the pin-to-pin connections for proper polarity.

Table 1: QSFP+ and QSFP28 Optical Module Receptacle Pinouts
Fiber	Signal
1	Tx0 (Transmit)
2	Tx1 (Transmit)
3	Tx2 (Transmit)
4	Tx3 (Transmit)
5	Unused
6	Unused
7	Unused
8	Unused
9	Rx3 (Receive)
10	Rx2 (Receive)
11	Rx1 (Receive)
12	Rx0 (Receive)

Table 2: QSFP+ MPO Fiber-Optic Crossover Cable Pinouts
Pin	Pin
1	12
2	11
3	10
4	9
5	8
6	7
7	6
8	5
9	4
10	3
11	2
12	1