So I've got some Juniper EX4500's. They're configured as a Virtual Chassis using the SFP+ ports. Due to the distance between racks, I wasn't able to use the VCP ports.

Anyway, I've run into an issue where I'm upgrading the JunOS from 12.3R9-S1 to 15.1R6.7.

It seems that the firmware update happens ok? Maybe? I see no errors that prevent the system from booting.

However, the problem occurs after the system is completely booted. The SFP+ ports used for the VCP connection come up. But the remaining standard network ports do not.

They appear on the system as being disconnected. Or not being connected, on the port indicators, it indicates that the SFP's and cables are connected. But it's still shut down?

I have tried to disable and re-enable the ports, but to no avail. This happens n all ports, whether they have SFP, SFP+ or Copper SFP's.

Is there a step that I am missing from this?

  • Did any answer help you? If so, you should accept the answer so that the question doesn't keep popping up forever, looking for an answer. Alternatively, you can provide and accept your own answer.
    – Ron Maupin
    Dec 25, 2018 at 9:33

1 Answer 1


Hello and welcome to Network Engineering!

Are you sure, that upgrade went correctly? Did you followed upgrade process and see no errors (even that you think wasn't too important)?

Possible case that I also had, it's configuration incompatibility between 12.x and 15.x versions of firmware. In my case EX3300 VC failed to upgrade to 15.x due to more strict configuration checks which lead to unrecoverable errors and I'd must to return back to 12.x via alternate slice.

To be sure, that no errors was raised, investigate console logs for upgrade process (if you have them) and after check logs in realtime.

And finally I would still recommend to create JTAC case. They have better chances to help you with problem.

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