When configuring a 2 member Virtual Chassis using 2xQFX5100, there is a slight difference compared to EX Series but it’s very much similar. As this is the case, I thought I’d do a quick post (And it doubles up as documentation writing for work lol). The QFX doesn’t have dedicated VC ports or a VC module, so with this in mind you’ll have to use either 10GB SPF+ port(s) or 40GB QSFP(s) ports to connect the switches together. The method is same as Configuring Virtual Chassis on EX switch using VCEP ports, the one difference is that with the QFX you can do the entire configuration with the VCEP port pre-connected, but this wasn’t the case with EX Series. However, similarly, it’s recommended that you have Backup Routing Engine (RE) or Linecard powered off if you’re using the preprovisioned method like I am :)

Let’s get cracking :D

In one of my previous post, Configuring Virtual Chassis on Juniper EX Series, it’s recommended that you have the following commands set before processing with configuring a Virtual Chassis:

set system commit synchronize
set chassis redundancy graceful-switchover
set routing-options nonstop-routing
set protocols layer2-control nonstop-bridging

The QFX non-bridging command is under the protocols layer2-control stanza NOT ethernet-switching-options stanza as on the EX Series

Once these have been committed, you can configure the virtual-chassis stanza.

show configuration virtual-chassis | display set 
set virtual-chassis preprovisioned
set virtual-chassis no-split-detection
set virtual-chassis member 0 role routing-engine
set virtual-chassis member 0 serial-number TA3715110057
set virtual-chassis member 1 role routing-engine
set virtual-chassis member 1 serial-number TA3715110028

Just like on EX Series, you have to set the VC-Ports on the Master Routing Engine for them to know those ports are being used as the Virtual Chassis interconnects

root@QFX-Bottom> request virtual-chassis vc-port set pic-slot 0 port 48 
root@QFX-Bottom> request virtual-chassis vc-port set pic-slot 0 port 50

You can power up (the Backup RE), having completed the entire configuration on the Master RE. Once the Backup has booted, as done on the Master, you have to set the 40GB QSFPs ports as the VC-Ports

root@QFX-Top> request virtual-chassis vc-port set pic-slot 0 port 48 
root@QFX-Top> request virtual-chassis vc-port set pic-slot 0 port 50

Once this is done, the Virtual Chassis is created and you’ll be kicked out of the Backup RE and will have to log back into the switch, where you will be logged into the Master Routing Engine. To verify that everything is working as expected you can run the commands show virtual-chassis vc-port and show virtual-chassis

show virtual-chassis vc-port⌗ 

root@QFX-Bottom> show virtual-chassis vc-port    
fpc0:
--------------------------------------------------------------------------
Interface   Type              Trunk  Status       Speed        Neighbor
or                             ID                 (mbps)       ID  Interface
PIC / Port
0/48        Configured          5    Up           40000        1   vcp-255/0/48
0/50        Configured          5    Up           40000        1   vcp-255/0/50

fpc1:
--------------------------------------------------------------------------
Interface   Type              Trunk  Status       Speed        Neighbor
or                             ID                 (mbps)       ID  Interface
PIC / Port
0/48        Configured          5    Up           40000        0   vcp-255/0/48
0/50        Configured          5    Up           40000        0   vcp-255/0/50

show virtual-chassis⌗ 

root@QFX-Bottom> show virtual-chassis 

Preprovisioned Virtual Chassis
Virtual Chassis ID: 1165.24bd.5581
Virtual Chassis Mode: Enabled
                                                Mstr           Mixed Route Neighbor List
Member ID  Status   Serial No    Model          prio  Role      Mode  Mode ID  Interface
0 (FPC 0)  Prsnt    TA3715110057 qfx5100-48s-6q 129   Master\*      N  VC   1  vcp-255/0/48
                                                                           1  vcp-255/0/50
1 (FPC 1)  Prsnt    TA3715110028 qfx5100-48s-6q 129   Backup       N  VC   0  vcp-255/0/48
                                                                           0  vcp-255/0/50

And you’re done! As I said, it’s very similar to configuring a Virtual Chassis on EX Series, except for a couple of small changes that could throw someone off if they didn’t know!

For more in-depth detail you can check Juniper’s TechLibrary page

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