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SFP28 Direct Attach Copper Cables for QFX5120 Switches


Small form-factor pluggable transceiver (SFP28) direct attach copper (DAC) cables, also known as Twinax cables, are suitable for in-rack connections between servers and switches. They are suitable for short distances, making them ideal for highly cost-effective networking connectivity within a rack and between adjacent racks.


We recommend that you use only SFP28 DAC cables purchased from Juniper Networks with your Juniper Networks device.


If you face a problem running a Juniper Networks device that uses a third-party optic or cable, the Juniper Networks Technical Assistance Center (JTAC) can help you diagnose the source of the problem. Your JTAC engineer might recommend that you check the third-party optic or cable and potentially replace it with an equivalent Juniper Networks optic or cable that is qualified for the device.

This topic describes:

Cable Specifications

QFX5120 switches support SFP28 passive DAC cables. The passive Twinax cable is a straight cable with no active electronic components. QFX5120 switches support 1  m, 3  m, and 5  m long SFP28 passive DAC cables. See Figure 1.

Figure 1: SFP28 Direct Attach Copper Cables for QFX5120 Switches
SFP28 Direct Attach Copper
Cables for QFX5120 Switches

The cables are hot-removable and hot-insertable: You can remove and replace them without powering off the switch or disrupting switch functions. A cable comprises a low-voltage cable assembly that connects directly into two 25-Gigabit Ethernet ports, one at each end of the cable. The cables use high-performance integrated duplex serial data links for bidirectional communication and are designed for data rates of up to 25  Gbps.

Standards Supported by These Cables

The cables comply with the following standards: