40G QSFP+ DAC Cable - 40GBASE-CR4 Passive Direct Attach Copper Twinax QSFP Cable for Ubiquiti, Dell Force10 CBL-QSFP-40GE-PASS-0.5M, Supermicro, Mikrotik, Open Switch Devices, 0.5-Meter(1.64ft)

I bought a pair of these to use in my home lab. My company sent me a pair of EX3400 switches. Rather than spending tons of money on optics and cables, I decided to try these out after a recommendation on reddit. I'm a CCNP R/S, but my specialty is VoIP. So I'm not always up to date on datacenter fabric connections.These worked like a charm, and I was able to set up a virtual chassis with little effort. I was able to split port channels between the chassis. Everything works exactly as I would want. No errors from the switches. I'm currently running Junos 20.4R1.12.Since this is a lab, I cant comment on how they'd hold up in an actual datacenter application. But I would imagine they would work just fine.

good cable, I run it at 40G, tested with iperf3, it gives me 33-34 Gbytes/s with Mellanox Connex 3 cards (switch on the middle) which i is very acceptable in my configuration

Its a cable, just very short.

Set up two switch stack with 4 Juniper EX4300s in each stack. I used the . 5 meter for the links between the individual switches and a 1 meter for the link between sw0 and sw3. -- hth

Works with Mellanox ConnectX3 VPI and Celestica DX010 switch at 40g.

Description states that it can run "up to 56Gb/s" when in actuality it can only run up to 40Gb/s (http://www.mellanox.com/page/cables; MC2206130-003 can only run at FDR10 which is 40GB/s). Other than that, it's a decent cable.--- Update ---I just wanted to give an update after running some more tests. These cables performed only slightly worse than our 56 Gbps AOC cables, simliar to 10Gtek 40G QSFP+ AOC, for IBM / Mellanox Active Optical Cable, 3-meter. We achieved 22.8 Gbps IPoIB with our AOC cables using iperf and got 22.3 Gbps with these copper cables. If you don't want to spend the extra money for optical cables and don't need to run long distances, this is a pretty good cable.

These just work. Each and every time.

Out of 9 cables I found two defective cables ( one was internally short cause my traffic tester to reboot and the other one has CRC error ) . One of the 9 cables received a week later too .