Can some one please tell that Juniper vMX supports how many logical system? Some one mentioned on Juniper forum that it supports 15 Logical systems but in case of 3 Logical systems configured , 2 were working find while third one not.

Is there a speical requirement to make more than 2 logical systems running fine? or we could run 8 or 15 logical systems with no issue

The number of logical systems are dependent on Junos software release?


  • I’ll get you an answer in a day or so. Apr 9 '20 at 15:31

The correct answer here is 15 logical systems. Currently that is the limit, though changes in software may come in the future.

On 18.3R1

jhead@vmx# commit check
error: Cannot configure more than 15 logical systems
error: configuration check-out failed

Just make sure you remember to consider that all scaling limitations for protocols, RIB, FIB, etc. apply to the global system and not per logical system.

  • Thank you very much for the answer. Since we are going to use logical systems and we are not utilizing any physical ports on the router (FPCs ) can we still configure 15 logical systems by just using VCP machine of vMX (RE) instead of using both VCP VFP (RE + PFE) of vMX? Apr 13 '20 at 14:54
  • If you're not using physical interfaces, you are going to have to use "Logical Tunnels (lt-x/y/z)" interfaces. Those still require the use of a PFE (vFPC), as that is how throughput is determined. Going into any more detail would warrant another question so that we can keep the topics separate and help anyone else who has the same questions. Apr 13 '20 at 17:17
  • Thank you Jordan for clarifying Apr 13 '20 at 17:23

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