So the systems I am using are MX960 MPC7e.

When I use the 1meter 100G DAC I have zero errors + zero packet loss.

When I use the 3meter 100G DAC cables I have packet loss & framing errors. I tried 3 DAC cables on 2 different sets of routers…all MX960 MPC7e.

These are 3rd party DAC cables, all from the same place, but what I do not understand is why the 1M cables work and the 3M are giving me errors. The only difference between the cables that I have noticed is that the 3M are 28AWG and the 1M are 30AWG.

Any ideas as to what the issue is? I would think it was just a bad cable, but all 3 of them seems a little strange.

  • Cheap substandard cables are common. It would be far stranger to me if you tried 3 from all different places and they all had the same behavior but at least that would indicate it might not be the cables.
    – user143703
    Aug 24, 2017 at 23:14
  • Been using this vendor for years, going through hundreds of the same DAC without issues, until these three Juniper ones... That is why I find it strange.
    – KrisGT
    Aug 25, 2017 at 0:47

1 Answer 1


It seems this issue was not only because of the length and gauge of the cable but also the design of the PCBs in the transceiver end. Switching to a 26AWG cable improved the performance of the cable enough to get rid of these errors.

Different gauge cables can still be used but would need to acquire them from a different source that has improved PCB.

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