Multi-Vrf; Multi-Vrf Overview - Brocade Communications Systems FastIron SX 800 Configuration Manual

Multi-VRF

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Multi-VRF overview....................................................................................................................................................................................... 557

• Configuring Multi-VRF................................................................................................................................................................................. 563
Multi-VRF overview
Virtual Routing and Forwarding (VRF) allows routers to maintain multiple routing tables and forwarding tables on the same router. A
Multi-VRF router can run multiple instances of routing protocols with a neighboring router with overlapping address spaces configured
on different VRF instances.
Some vendors also use the terms Multi-VRF CE or VRF-Lite for this technology. VRF-Lite provides a reliable mechanism for a network
administrator to maintain multiple virtual routers on the same device. The goal of providing isolation among different VPN instances is
accomplished without the overhead of heavyweight protocols (such as MPLS) used in secure VPN technologies. Overlapping address
spaces can be maintained among the different VPN instances.
Central to VRF-Lite is the ability to maintain multiple VRF tables on the same Provider Edge (PE) Router. VRF-Lite uses multiple
instances of a routing protocol such as OSPF or BGP to exchange route information for a VPN among peer PE routers. The VRF-Lite
capable PE router maps an input customer interface to a unique VPN instance. The router maintains a different VRF table for each VPN
instance on that PE router. Multiple input interfaces may also be associated with the same VRF on the router, if they connect to sites
belonging to the same VPN. This input interface can be a physical interface or a virtual Ethernet interface on a port.
In Multi-VRF deployments:
• Two VRF-capable routers must be directly connected at Layer 3, deploying BGP, OSPF, RIP, or static routes.
• Each VRF maintains unique routing and forwarding tables.
• Each VRF can be assigned one or more Layer 3 interfaces on a router to be part of the VRF.
• Each VRF can be configured with IPv4 address family, IPv6 address family, or both.
• A packet's VRF instance is determined based on the VRF index of the interface on which the packet is received.
• Separate routing protocol instances are required for each VRF instance.
• Overlapping address spaces can be configured on different VRF instances.
Multi-VRF deployments provide the flexibility to maintain multiple virtual routers, which are segregated for each VRF instance. The
following illustrates a generic, high-level topology where different enterprise functions are assigned unique VRF instances.
FastIron Ethernet Switch Layer 3 Routing
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