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vJunos-switch Overview

SUMMARY This topic provides an overivew, key features supported, benefits, and limitations of the vJunos-switch.


Read this topic for an overview of the vJunos-switch.

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

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

The vJunos-switch is a single virtual machine (VM) that you can use only in labs and not in the production environment. The vJunos-switch is built using EX9214 as a reference Juniper switch and supports a single Routing Engine and single Flexible PIC Concentrator (FPC).

The vJunos-switch supports a bandwidth of up to 100 Mbps aggregated over all the interfaces. You don't need to purchase a bandwidth license for using the vJunos-switch.

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

vJunos-switch Installation Overview

You can install the software components of the vJunos-switch 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 vJunos-switch instances on a single server.

Key Features Supported

This topic provides you the list and details of the key features that are supported and validated on vJunos-switch. For details on configuration of these features see the feature guides at: User Guides.

The vJunos-switch supports the following key features:

  • Supports up to 96 switch interfaces

  • Can simulate data center IP underlay and overlay topologies.

  • Supports EVPN-VXLAN leaf functionality

  • Supports Edge-Routed Bridging (ERB)

  • Supports EVPN LAG multihoming in EVPN-VXLAN (ESI-LAG)

Benefits and Uses

The benefits and use cases of the vJunos-switch on standard x86 servers are as follows:

  • Reduced capital expenditure (CapEx) on lab—The vJunos-switch is available for free to build test labs reducing costs associated with physical switches.

  • Reduced deployment time—You can use the vJunos-switch to build and to test topologies virtually without building expensive physical labs. Virtual labs can be built instantly. As a result, you can reduce costs and delays associated with deployments on the physical hardware.

  • Eliminate need and time for lab hardware—The vJunos-switch helps you eliminate waiting time for lab hardware to arrive after procurement. vJunos-switch is available for free and can be downloaded instantly.

  • Education and training—Allows you to build labs for learning and education services for your employees.

  • Proof of concept and validation testing—You can validate various data center switching topologies, pre-build configurations examples, and get automation ready.


The vJunos-switch has the following limitations:

  • Has a single Routing Engine and single FPC architecture.

  • Does not support in-service software upgrade (ISSU).

  • Does not support attachment or detachment of interfaces when it is running.

  • SR-IOV for the vJunos-switch use cases and throughput is not supported.

  • Due to its nested architecture, the vJunos-switch cannot be used in any deployments that launch the instances from within a VM.

  • Supports a maximum bandwidth of 100 Mbps over all the interfaces.


    Bandwidth licenses are not provided as there is no need for a bandwidth license.

    License check message might come up. Ignore the license check messages.

  • You cannot upgrade the Junos OS on a running system. Instead, you must deploy a new instance with the new software.

  • Multicast is not supported.