Help us improve your experience.

Let us know what you think.

Do you have time for a two-minute survey?


What is vJunosEvolved

SUMMARY This topic provides an overivew, key features, benefits, and limitations of vJunosEvolved.


vJunosEvolved is a virtual version of a Juniper switch that runs the Junos OS Evolved. You can install a vJunosEvolved as a virtual machine (VM) on an x86 server.

You can configure and manage the vJunosEvolved in the same way as you manage a physical switch.

vJunosEvolved is a single virtual machine (VM) that you can use only in labs and not in the production environment. The vJunosEvolved is built using PTX10001-36MR as a reference Juniper switch, which is a fixed-configuration packet transport router on the Junos® OS Evolved platform.

The vJunosEvolved Routing Engine and the vBT-COSIM (a virtual BT chip) that performs the packet processing run on the same VM.

Instead of using hardware switches, you can use the vJunosEvolved to start the Junos software for testing the network configurations and protocols.

The vJunosEvolved virtual platform primarily acts as a test platform for lab simulations for the customers.


Bandwidth licenses are not required and are not provided. You can ignore any license check messages if you get an alert.

vJunosEvolved Installation Overview

You can install the software components of vJunosEvolved on an industry-standard x86 server running a Linux KVM hypervisor (Ubuntu 18.04, 20.04, 22.04 or Debian 11 Bullseye).

On servers running the KVM hypervisor, you can also run applicable third-party software. You can install multiple vJunosEvolved instances on a single server.

Key Features

This topic provides you a list of key features that the vJunosEvolved platform supports.

The vJunosEvolved platform supports the following key features:

  • Supports up to 12 switch interfaces and 25 channelized interfaces.
  • Can simulate data center IP underlay and overlay topologies.
  • Supports EVPN-VXLAN leaf and spine functionality
  • Support EVPN-VXLAN border functionality (Type 5 to Type 5 stitching currently)
  • Supports EVPN LAG multihoming in EVPN-VXLAN (ESI-LAG)

For details on configuration of these features, refer to Software Documentation.

Benefits and Uses

The benefits and use cases of vJunosEvolved on standard x86 servers are as follows:

  • Reduce capital expenditure on physical lab—You can use the vJunosEvolved platform for free to build test labs. This reduces the costs associated with physical switches and routers.

  • Reduce deployment time—You can use the vJunosEvolved platform to build and test topologies virtually without building expensive physical labs. You can build virtual labs instantly, which helps in reducing costs and delays related to physical hardware deployment.

  • Eliminate lab hardware—You can eliminate using lab hardware by downloading the vJunosEvolved platform instantly and for free

  • Educate and train—You can use the vJunosEvolved platform to build labs for learning and education services for your employees.

  • Automate, build, and validate—You can use the vJunosEvolved platform to validate various data center switching and routing topologies, pre-build configurations examples, and get automation ready.

The vJunosEvolved is intended only for lab use and not for commercial deployment.


The vJunosEvolved has the following limitations:

  • The vJunosEvolved has a fixed-form Junos OS Evolved architecture.

  • You cannot upgrade vJunosEvolved on a running system. Instead, you can deploy a new instance with the new software.

    The vJunosEvolved does not support in-service software upgrade (ISSU).

    You cannot attach or detach interfaces while vJunosEvolved is running.

  • Supports a maximum bandwidth of 2 Kpps or 3-5 Mbps over all the interfaces.
  • To channelize WAN interfaces, run a boot argument with channelized=yes that is specified in the VM config and the interfaces speed config at vJunosEvolved CLI.

    Example: set interfaces et-0/0/0 speed 25g number-of-sub-ports 8

  • For non-channelization, channelized=no is the default config.

  • vJunosEvolved does not support single-root I/O virtualization (SR-IOV)

  • COSIM reliably works up to 2000 pps across 128B-1500B packet length. You do not need a bandwidth license.

  • Currently maximum of 25 channelized interfaces are supported. Provisioning the 26th channelized interface leads to unstable system behavior or VM crash and is not advised.
  • For vJunosEvolved to function correctly as a Virtual Extensible LAN (VXLAN) Tunnel End Point (VTEP), you must configure tunnel termination using the set forwarding-options tunnel-termination command. Otherwise the traffic in the tunnel drops on the egress VTEP.

vJunosEvolved does not support the following features:

  • Port mirroring

  • Storm control

  • Multichassis link aggregation (MC-LAG)

  • VXLAN seamless stitching for Data Center Interconnect (DCI)

  • Virtual Router Redundancy Protocol (VRRP)

  • Multicast

  • Q-in-Q tunneling through an Ethernet VPN–Virtual Extensible LAN (EVPN-VXLAN) fabric

  • Layer-2 egress filtering on EVPN-VXLAN-enabled integrated routing and bridging (IRB) interfaces

  • IPv6 underlay and overlay

  • MAC filtering in EVPN-VXLAN fabric using a MAC list

  • EVPN-VXLAN fabric enhanced loop detection using connectivity fault management (CFM)