Understanding how these split-architecture components interact via QEMU is critical for network engineers building BGP EVPN/VXLAN data center topologies in non-production environments. Understanding the Split Architecture Architecture
Use show chassis hardware to verify both RE and PFE are loaded.
The PFE receives forwarding tables from the RE and maps them to virtual external interfaces (like xe-0/0/0 , xe-0/0/1 ) to pass traffic to other lab devices. Requirements for Deployment
: Frequently packaged as a separate cosim (cosmulation) QCOW2 image. It processes simulated data plane traffic and handles packet manipulation.
This creates a new, empty QCOW2 image named my-disk.qcow2 with a maximum size of 10GB.
: Optimized for KVM-based hypervisors, this format allows for thin provisioning, meaning the file only consumes physical disk space as data is written. 2. Deployment Prerequisites
Log into the Junos CLI and verify chassis network services via show chassis fpc . If the slot shows "Offline," restart the PFE instance entirely.
Unlike straightforward virtual machines, the vQFX relies on a to mimic bare-metal hardware. To form a completely functional node, you must orchestrate two separate QEMU images simultaneously:
Always ensure your RE and VFP are connected via their second adapter ( em1 to eth1 ). This creates the internal "chassis" link.
To function correctly, the vQFX requires two separate virtual machines working in tandem:
This article explains exactly how to make vqfx202r110re-qemu.qcow2 work, from proper conversion to advanced troubleshooting.
The RE image ( vqfx-20.2R1.10-re-qemu.qcow2 ) cannot forward data plane traffic on its own . It will boot to a JunOS prompt, but any network interfaces you configure will remain operationally "down" until it is linked via a dedicated internal virtual connection to a running PFE node. 2. Understanding the "20.2 vs 19.4" Version Paradox
: Avoid CPU contention by pinning each vQFX to physical cores.
Fix the permissions via the EVE-NG CLI: /opt/unetlab/wrappers/unl_wrapper -a fixpermissions Importing into GNS3 Open GNS3 and go to -> QEMU VMs -> New . Name the template vQFX-RE-20.2R1.10 .
