Vqfx-20.2r1.10-re-qemu.qcow2 [INSTANT | 2025]

In the world of network engineering, the gap between theory and practice has traditionally been bridged by expensive hardware. For decades, mastering a platform like Juniper’s Junos OS meant investing in physical routing and switching platforms. However, the virtualization revolution has democratized network engineering. At the heart of this revolution for Juniper enthusiasts lies a specific, powerful file: Vqfx-20.2r1.10-re-qemu.qcow2.

This seemingly cryptic string represents a specific snapshot of Juniper’s virtualized data center switching platform. For students, DevOps engineers, and network architects, understanding what this file is, how to use it, and its specific version nuances is critical for building accurate, high-performance virtual labs.

This article will deconstruct the file name, explore its architecture, provide a setup guide, and discuss its role in modern network automation workflows. Vqfx-20.2r1.10-re-qemu.qcow2

Prerequisites:

Basic KVM command (RE only, no data plane): In the world of network engineering, the gap

qemu-system-x86_64 \
  -name vqfx-re \
  -m 4096 \
  -smp 2 \
  -drive file=Vqfx-20.2r1.10-re-qemu.qcow2,if=ide,index=0 \
  -netdev user,id=mgmt,net=192.168.76.0/24,dhcpstart=192.168.76.10 \
  -device e1000,netdev=mgmt \
  -nographic \
  -serial telnet:127.0.0.1:5001,server,nowait

Login:

Connect to your EVE-NG server via SSH and create a directory for the vQFX. Prerequisites:

mkdir /opt/unetlab/addons/qemu/vqfx-20.2r1.10

Once you start the node in your simulator:

  • CLI Start: 
    root@:~ # cli
root@> edit
  • Verify PFE Connection: Check if the RE can see the PFE (Forwarding Plane). Run: 
    root@# run show chassis fpc
    You should see the FPC status as Online. If it is offline or empty, the link between your RE image and PFE image is broken.
    • qemu-img snapshot -l Vqfx-20.2r1.10-re-qemu.qcow2

    qemu-img snapshot -c "snapshot_name" Vqfx-20.2r1.10-re-qemu.qcow2

    Given the version is 20.2 (circa 2020), it is outdated for production but useful for:

    | Use Case | Viability | | :--- | :--- | | Production Data Center | ❌ Not recommended. Vulnerabilities, missing features (EVPN-VXLAN enhancements, MACsec). | | Lab / Certs (JNCIP-DC, JNCIE) | ✅ Good. Many training materials still reference 20.2. | | Home EVPN Lab | ⚠️ Limited. 20.2 supports EVPN but has known bugs (BUM flooding, ARP suppression). | | Network Automation Testing (Ansible, PyEZ) | ✅ Yes. Junos 20.2 has stable NETCONF/REST APIs. | | CI/CD Pipeline | ⚠️ Risky. Use latest (23.4+) for CI. |

    Assuming you want to add a feature like: