What is a Virtual Router?

A Virtual Router (VR) is a software object on a Versa VOS device that performs the functions of a hardware Layer 3 IP router: its own routing table, its own interface assignments, and its own static and dynamic routing protocols, isolated from every other VR on the same appliance.

Key takeaways

• A VR is a software routing instance that behaves like a physical router.
• Each VR keeps its own routing table and interface assignments.
• Common roles include LAN VR, WAN/transport VR, and management VR.
• VRs run OSPF, OSPFv3, BGP, and static routing independently per instance.
• VRs isolate tenant traffic and segment routing between organizations.

On this page: Why it matters · How it works · Types · Virtual Router & Versa · FAQ

Why are virtual routers important?

A single appliance often needs to keep several routing domains apart – LAN traffic, WAN transport, management traffic, and separate tenants – without those domains leaking into one another or fighting over the same routing table. A VR gives each domain its own isolated routing context on shared hardware: overlapping IP address ranges between two VRs are safe, a route learned in one VR never leaks into another unless explicitly redistributed, and a fault or misconfiguration in one VR’s routing table doesn’t touch its neighbors.

That isolation is also what makes segmentation and multitenancy practical at the routing layer. Instead of deploying separate physical routers per traffic type or per customer, one VOS device hosts multiple VRs, each behaving like its own independent router with its own protocols, policies, and interfaces. It’s the same principle behind virtual routing and forwarding (VRF) in general networking, applied as the core routing construct throughout Versa’s platform.

What is a virtual router?

Functionally, a VR is a software object that does what a hardware-based Layer 3 IP router does: it holds a routing table, forwards packets between its assigned interfaces, and runs the same protocols an appliance would – static routes, OSPF and OSPFv3, BGP, and multicast routing – plus redistribution and import policies between protocols. Interfaces and networks are explicitly assigned to a VR, and only that VR’s routing table governs how traffic on those interfaces is forwarded.

A VR is, at its core, a routing instance: a named, reusable forwarding context referenced wherever an interface, monitor, or policy needs to specify which routing domain it belongs to. That’s why VRs are the mechanism Versa uses to isolate tenant traffic and to segment routing between interfaces and organizations – every tenant, and every functional traffic type within a tenant, can be given its own VR.

Types of virtual routers

Every VR is created as one of two instance types. A Virtual Routing Instance is the basic type, used to configure a simple VPN-style routing context. A Virtual Routing Forwarding Instance (VRF) configures a router for Layer 3 VPN, with optional MPLS VPN core or EVPN core settings for connecting Layer 2 domains over an MPLS or IP underlay.

Independent of instance type, deployments commonly name VRs by the role they play: a LAN VR carries a tenant’s local-network traffic and routing protocols, a WAN/transport VR handles routing toward WAN links and next hops, a management VR carries device-management traffic separately from tenant data, and a dedicated HA control VR can carry the synchronization traffic between an active and standby appliance pair in a high-availability deployment.

Virtual Router & Versa

In Versa Director, a VR is created and configured from Appliance view under Configuration > Networking > Virtual Routers: instance name, instance type, interfaces, static routes, and dynamic-routing instances such as OSPF, OSPFv3, and BGP are all configured inside the same Configure Virtual Router workflow. Each OSPF or BGP instance runs inside its own VR, with its own router ID, areas, and neighbor policies, independent of any other VR on the device.

VRs also carry Versa-specific infrastructure traffic. In stateful interchassis HA designs, administrators create a dedicated VR (for example, HA-Control-VR) purely to carry the data-sync connection between active and standby devices, separate from the customer’s LAN VR. And when installing Versa VNFs on Azure without a CMS connector, the customer’s LAN VR is where the BGP instance that peers with Azure’s own virtual router BGP endpoint gets configured – two different “virtual router” concepts, Versa’s VR and Azure’s managed routing service, exchanging routes with each other over a standard eBGP session.

Frequently asked questions

What is the difference between a virtual router and a physical router?

A virtual router is a software object running on a VOS appliance rather than dedicated hardware. It performs the same Layer 3 functions – routing table, interface forwarding, static and dynamic routing protocols – but several VRs can run isolated from each other on one physical device.

What is the difference between a Virtual Routing Instance and a Virtual Routing Forwarding Instance?

A Virtual Routing Instance is the basic VR type, used to configure a simple VPN-style routing context. A Virtual Routing Forwarding Instance (VRF) configures a router for Layer 3 VPN, with optional MPLS VPN core or EVPN core settings for connecting domains over an MPLS or IP underlay.

What roles do virtual routers commonly play on a VOS device?

Deployments typically separate a LAN VR for local tenant traffic, a WAN/transport VR for routing toward WAN links, and a management VR for device-management traffic. High-availability designs sometimes add a dedicated VR purely to carry the sync connection between active and standby appliances.

Can a virtual router run routing protocols like OSPF and BGP?

Yes. Each VR supports its own static routes plus dynamic routing instances – OSPF, OSPFv3, and BGP – configured independently of every other VR on the device, each with its own router ID, areas, or peer groups, so protocol state in one VR never affects another.

How does a virtual router relate to a routing instance?

A VR is a routing instance – the two terms describe the same object. “Routing instance” is the general term used when configuring interfaces, monitors, or policies that reference which routing context they belong to; “virtual router” is the object created and named in Director’s Networking configuration.

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