We want to setup Virtual Chassis using 2 x Juniper EX4200 switches. In case of Virtual Chassis for EX4200 , we have to use 2 x VC cables (connected back to back) between 2 x Ex4200 switches along with virtual chassis configuration.

However , we have only 1 x VC cable for Virtual Chassis creation which can do the job of Virtual Chassis setup. (VC cable is dedicated cable used for VC setup). But 1 x VC cable is not enough from redundancy standpoint. EX4200 switches also houses 10G SFPs as respective modules are installed in both switches. 10G ports can also be used as VC ports for Virtual Chassis setup as per Juniper documentation plus they also mention configuration required to use 10G port as VC port.

With respect to our scenario , is it possible to setup Virtual Chassis using 1 x VC cable (dedicated VC cable) along with 10G SFPs (from both switches) as VC ports?

Will this mixed interface types (VC cable + 10G SFP) for VC setup work? Since 2 x VC ports would be enough both from VC setup and from redundancy standpoint.


  • I've never tries it myself, but the docs I've read suggest all VC links must be of the same type/speed. If this is in a lab setting, try it and see what happens.
    – Ricky
    Oct 23 '20 at 0:25

If you are only talking about traditional Virtual Chassis (VC) (ring topology) then yes you can mix dedicated VCP and uplink ports converted into VCP (10G/1G). Please refer to the EX4200 section of the documentation.

If you are looking at using Virtual Chassis Fabric (VCF) (Clos topology), it should still work, but I didn't confirm this. You'd probably run into unintended congestion/oversubscription issues as failures occur.

  • Thank you for replying. We have also tested this in our environment and it works. Oct 23 '20 at 14:56
  • @JordonHead. I observed there is a speed difference between dedicated VC port and using 10G port as VC . The dedicated VC port has 32G speed while 10G will be working on 10G. Will that be an issue as both VC ports will used for traffic and control plane packets? Thanks Oct 26 '20 at 15:46
  • For the EX4200 it's 16G in each direction, so 32G is correct. I doubt you're going to generate enough control plane traffic to cause any issues. That said, sure if you did generate enough you could get packet loss, just like any other kind of traffic. Oct 26 '20 at 16:03
  • I m sure there wouldn't be enough traffic to hit capacity. Hence no issue in our case. Oct 26 '20 at 16:37

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