Running the Juniper vQFX image vqfx-20.2R1.10-re-qemu.qcow2 requires understanding that vQFX operates as a split-brain system consisting of two separate virtual machines: the Routing Engine (RE) Packet Forwarding Engine (PFE) Cisco Learning Network Core Setup Requirements
To get this specific image working, you must pair it with a compatible PFE image (typically named something like vqfx-pfe-qemu.qcow cosim.qcow2
). The switch will not pass traffic unless both components are running and interconnected. RE (Routing Engine): This is your vqfx-20.2R1.10-re-qemu.qcow2 file. It runs Junos and handles the control plane. PFE (Packet Forwarding Engine):
This handles the data plane. Without it, your interfaces will show as "up" but won't actually switch traffic. The "Trick": Connect the interface of the RE directly to the
interface of the PFE. This internal link allows the two "brains" to communicate. Cisco Learning Network Implementation in Lab Environments Guide: Importing Juniper vMX and vQFX into CML2.4
vqfx-20.2R1.10-re-qemu.qcow2 refers to the Routing Engine (RE) image for Juniper's
virtual switch. It is a virtualized version of the physical QFX10000 data center switch, designed for network simulation, configuration testing, and automation development. brezular.com Core Image Details Version Note: Although the filename indicates
, several users and platforms report that this specific download is often actually version 19.4 Dual-VM Architecture: The vQFX requires two separate VMs to function as a single logical device: Routing Engine (RE): Runs the Junos OS control plane. Packet Forwarding Engine (PFE): Handles the data plane (traffic forwarding). Juniper Elevate Community Key Features & Capabilities The vQFX allows you to emulate nearly all control plane features of a physical Juniper vQFX - - EVE-NG
Upload the downloaded images to the EVE newly created directories using. Juniper vQFX on GNS3 - Brezular's Blog
Juniper vQFX on GNS3 * Creating vQFX RE VM. Navigate to Edit-> Preferences-> Qemu VMs and click the New. Choose the the name vQFX- brezular.com Juniper vQFX RE - GNS3
To get the Juniper vQFX 20.2R1.10 (vqfx-20.2R1.10-re-qemu.qcow2) working correctly, you must pair it with its corresponding Packet Forwarding Engine (PFE) image. Unlike typical routers, the vQFX is a split-architecture virtual switch where the Routing Engine (RE) handles the control plane and the PFE handles the data plane. Core Components Required RE Image: vqfx-20.2R1.10-re-qemu.qcow2.
PFE Image: vqfx-20.2R1-2019010209-pfe-qemu.qcow (often bundled with the 20.2 download).
Note on Versioning: Even if the filename says 20.2, running show version within Junos may report 19.4R1. This is a known labeling discrepancy from the Juniper portal. Basic Configuration Steps Guide: Importing Juniper vMX and vQFX into CML2.4
The request landed on Tariq’s terminal at 11:47 PM: REQ-VQFX-202-R110 / EMU / QCOW2.
He sighed. The lab’s physical switches were already racked and cabled for the new data center simulation, but the budget had been cut. Again. No hardware meant he had to build the entire spine-leaf topology in software. vqfx202r110reqemuqcow2 work
"Alright, 'R110'," he muttered, pulling up the automation script. "Let's see if you work."
The vqfx202 was his go-to virtual switch—a tiny, fierce Juniper vQFX that acted like a 10-pound bruiser in a 1-pound sack. But the R110 requirement was the problem. The latest release. Buggy. Unforgiving.
He downloaded the vqfx202-r110.qcow2 image—the golden QEMU copy-on-write file. It was pristine. Untouched. He’d learned long ago never to trust the raw images.
"Step one: clone," he whispered, typing:
qemu-img create -f qcow2 -b vqfx202-r110.qcow2 vqfx202-lab1.qcow2
The terminal blinked back: Formatting 'vqfx202-lab1.qcow2', fmt=qcow2 size=...
Good. The backing file was intact. He spun up the first emu instance—QEMU with PCI pass-through for the virtual ASICs.
qemu-system-x86_64 -machine pc -cpu host -smp 2 -m 4096 \
-drive file=vqfx202-lab1.qcow2,if=ide,index=1,media=disk \
-device virtio-net-pci,netdev=leaf1_int ...
The console flickered. Juniper’s loader chugged. Then—green text.
FreeBSD/x86 (vqfx202-re) (ttyu0)
He was in. The RE (Routing Engine) was alive.
"Ping the spine," he commanded the script. And silence.
No. Not silence—thundering quiet. The virtual links were down. He checked the bridge interfaces. The MACs were there. The VLAN tags matched. But the vqfx202 was stubborn as a mule.
Then he remembered: the R110 release had a new quirk. It required explicit set chassis fpc 0 pic 0 tunnel-services for the virtual fabric links. The old R90 didn't need it.
He patched the configuration via netconf-console, holding his breath.
commit complete.
He launched a second emu instance—another leaf—and watched the LLDP neighbors crawl across the console like electronic ants.
System > vqfx202-re2 | Link: up | Protocol: up
"Work, you beautiful bastard," he grinned.
And it did. The tiny virtual spine saw the leaves. The leaves saw the hosts. Traffic flowed—not at 100G, but at virtual speed, enough for the devs to test their BGP policies.
At 2:13 AM, Tariq closed his laptop. The lab was running. 16 virtual switches, 32 host emulators, all eating RAM like candy, but holding steady.
He wrote in the handover log:
REQ-VQFX-202-R110 – Deployed. QCOW2 snapshots taken. EMU instances stable.
Note: tunnel-services required. Works. Barely. Don't touch until Monday.
Then he smiled. Another impossible request, shipped. Because at the end of the day, if you know how to bend QEMU, QCOW2, and Juniper’s will to your own… anything can work.
The keyword vqfx202r110reqemuqcow2 refers to a specific virtual disk image file for the Juniper Networks vQFX virtual switch. Specifically, it represents the Routing Engine (RE) component of the vQFX, running Junos OS version 20.2R1.10 in a QEMU-compatible QCOW2 format. Understanding vQFX Architecture
To make this image "work," it is essential to understand that a vQFX instance requires two distinct virtual machines (VMs) running in tandem:
Routing Engine (RE): The control plane that runs the Junos OS and manages configuration.
Packet Forwarding Engine (PFE): The data plane (often referred to as the "Cosim" or PFE image) that handles actual traffic forwarding.
A common point of confusion is that the vqfx-20.2R1.10-re-qemu.qcow2 file downloaded from Juniper's portal has been reported by users to sometimes identify itself internally as version 19.4R1.10. Setting Up vQFX in Lab Environments
To deploy this image successfully in popular network simulators like GNS3 or EVE-NG, follow these core requirements: 1. Image Requirements and Resources Running the Juniper vQFX image vqfx-20
RAM: Assign at least 1024 MB (GNS3) to 2048 MB (EVE-NG) for the RE. The PFE typically requires more, up to 4096 MB in some configurations. CPU: 1-2 vCPUs.
Virtualization: KVM acceleration must be enabled on the host. 2. Critical Connectivity
The RE and PFE must be interconnected for the switch to function.
RE Interface em1 must connect directly to PFE Interface em1.
User-defined switch ports are typically mapped to the RE VM (unlike the vMX, where they map to the PFE). RE Interface em0 is used for the management/admin VLAN. 3. Deployment Steps (General) Juniper vQFX RE - GNS3
vqfx-sys-kernel-junosCause: Incomplete image build (user overlay missing).
Fix: Re-extract from official .tgz distribution:
tar -xzvf vqfx-20.2R1.10.tgz
qemu-img convert -O qcow2 vqfx.raw vqfx202r110reqemuqcow2
The file vqfx202r110reqemuqcow2 refers to the Juniper vQFX virtual appliance image. This specific release (20.2R1.10) is a virtualized instance of the QFX Series switch, designed to run on x86 hardware using the QEMU hypervisor format (qcow2).
It is typically used for:
Feature Name: Auto-provision + gRPC Telemetry Exporter
Target: vqfx202r110reqemuqcow2
Goal: When the vQFX boots, it:
Start the VM:
virsh start vqfx20-re
virsh console vqfx20-re
You should see Juniper bootloader (GRUB) output. If the system hangs at “Loading initrd…” — the image is either corrupted or the VM lacks sufficient RAM/CPU.
For traffic forwarding tests (e.g., VXLAN routing), the RE alone won’t work. You need a separate vQFX PFE image (vqfx202r110pfe.qcow2). Connect them via a virtual back-to-back link using a socket or vhost-user interface.
Simplify by using Juniper vLab or containerlab with the following topology:
name: vqfx-evpn-lab
topology:
nodes:
spine:
kind: juniper_vqfx
image: vqfx202r110re-qemu.qcow2
startup-config: spine.cfg
leaf1:
kind: juniper_vqfx
image: vqfx202r110re-qemu.qcow2
links:
- endpoints: ["spine:ge-0/0/0", "leaf1:ge-0/0/0"]
Step 1: Image Acquisition
This specific file (vqfx-20.2R1.10-re-qemu.qcow2) is available to authorized Juniper customers via the Juniper Networks Support Portal (Software Download Center). The request landed on Tariq’s terminal at 11:47
Step 2: Deployment (Example for Eve-NG)
vqfx202r110reqemuqcow2 file as the primary disk image for the RE role.Step 3: Initial Configuration Upon booting the image, access the console:
root / no password (or juniper/juniper123 depending on pre-config).cliconfigure
set system services ssh
set system services netconf ssh
set interfaces fxp0 unit 0 family inet address <IP-Address>/<Subnet-Mask>
commit