Routing Instances Overview

A routing instance is a routing entity for a router. You can create multiple instances of BGP, IS-IS, OSPF, OSPFv3, RIP, and static routes. Each instance contains a routing table, applied routing policies, routing table group, interfaces that belong to that instance, and a protocol-specific route configuration related to that instance.

You configure a primary routing instance at the [edit protocols] hierarchy level. You configure additional routing instances at the [edit routing-instances] or [edit logical-systems logical-system-name routing-instance] hierarchy level.

You use routing instances to:

• Create administrative separation in a large network to segregate customer traffic and associated settings. The customers see only the routes belonging to them.
• Create overlay networks in which separate services are routed only towards routers participating in that service, such as voice. The overlay network isolates routes belonging to one service from another service by exporting routes, applying tags, and filtering based on tags.

Each routing instance consists of sets of the following:

• A set of routing tables
• A set of interfaces that belong to these routing tables
• A set of routing option configurations

Each routing instance has a unique name and a corresponding IP unicast table. For example, if you configure a routing instance with the name my-instance, its corresponding IP unicast table will be my-instance.inet.0. All routes for my-instance are installed into my-instance.inet.0.

Routes are installed into the default routing instance inet.0 by default, unless a routing instance is specified.

For details about specifying interfaces, see the JUNOS Network Interfaces Configuration Guide.

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