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EX Switch routing-instances



Article ID: KB16081 KB Last Updated: 07 Jan 2010Version: 1.0
This article provides information about routing-instances for the EX Switch and their purpose.

Multiple instances can be created for BGP, IS-IS, LDP, Multicast Source Discovery Protocol (MSDP), OSPF version 2 (OSPF), OSPF version 3 (OSPFv3), Protocol Independent Mutlicast (PIM), RIP, and static routes by including following statements at the following hierarchy levels:

* [edit routing-instances routing-instance-name protocols]

* [edit logical-systems logical-system-name routing-instances routing-instance-name protocols]

A routing instance is a collection of routing tables, interfaces and routing protocol parameters. The set of interfaces belongs to the routing tables, and the routing protocol parameters control the information in the routing tables.

You can configure five types of routing instances on the EX Switch:

1. Forwarding
2. L2VPN
3. Non Forwarding
4. Virtual-router
5. VRF
Each routing instance has a unique name and corresponding IP unicast table. For example, if you configure a routing instance with the name my-instance, the corresponding IP unicast table is myinstance.inet.0. All routes for my-instance are installed into my-instance.inet.0.

NOTE: The default routing instance, master, refers to the inet.0 routing table. The master routing instance is reserved and cannot be specified as a routing instance.

Forwarding - Use this instance type for filter-based forwarding applications. For this instance type, there is no one-to-once mapping between an interface and a routing instance. All interfaces belong to the default instance inet.0.

Layer 2 VPN (L2VPN) - Use this routing instance type for Layer 2 virtual private network (VPN) implementations.

Non Forwarding- Use this routing instance type when a separation of routing table information is required. There is no corresponding forwarding table. All routes are installed into the default forwarding tables. IS-IS instances are strictly non forwarding instance types.

Virtual Router - Similar to a VPN routing and forwarding instance type, but used for non-VPN-related applications. There are no virtual routing and forwarding (VRF) import, VRF export, VRF target, or route distinguisher requirements for this instance type.

VRF - Use the VPN routing and forwarding (VRF) instance type for Layer 3 VPN implementations. This routing instance type has a VPN routing table as well as corresponding VPN forwarding table. For this instance type, there is a one-to-one mapping between an interface and a routing instance. Each VRF instance corresponds with a forwarding table. Routers on an interface go into the corresponding forwarding table.

NOTE: Please refer to JUNOS Technical Documentation "Routing Protocols" for further details if required.

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