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To the best of my knowledge, the concept of VRF is something that exists only in the Cisco World. Other vendors refer to this concept as VPN, which is in other words, a way to keep routing tables separated within a router.

Knowing that what is the meaning of VRF-Lite and how vendors refer to this concept?

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    A VPN has nothing to do with a VRF.
    – Ron Maupin ♦
    Sep 5 '18 at 12:04
  • Ok, but how is VRF concept identified outside cisco?
    – user
    Sep 5 '18 at 12:41
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    As a VRF. The term is not specific to Cisco. A full-blown VRF implementation can use VPNs to transport routing updates, but VPNs are not dependent on VRFs.
    – Ron Maupin ♦
    Sep 5 '18 at 12:47
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VRF (virtual routing and forwarding) is a core technology of MPLS which allows a service provider to provide BGP routing to many customer VPNs while isolating each customer's routing tables.

VRF lite provides the same isolation in an enterprise LAN.

Imagine you have a corporate LAN with a number of VLANs and a default gateway to the corporate WAN.

If you want to add a guest VLAN with a default gateway to the internet, you can simply exclude it from the corporate LAN by not providing a switched virtual interface (interface Vlan on Cisco) on the guest VLAN.

Now suppose you need a second guest VLAN and you need to route between the two guest VLANs and the Internet without opening a hole to the corporate LAN.

This is a use case for VRF lite. On each layer 3 switch or router, you create a VRF for the corporate LAN and a VRF for the guest LAN. You map the VLANs to the appropriate VRFs. There are now two separate routing tables and no traffic can pass between them (unless you specifically configure that).

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VRF lite is used to separate router interfaces within the routing tables. It can be used when multiple customers share a router. Full blown VRF has the full MP-BGP across the MPLS and can be shared across multiple sites/locations.

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  • So If I understood correctly, the VRF lite is a concept referred locally on a single router, whereas the VRF is the extension of the same concept when shared across multiple sites/locations. Why did you mention MPLS?
    – user
    Sep 5 '18 at 15:20
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VRF-Lite is to use VRF without MPLS.:) With VRF across service-provider network, MPLS is used to carry route information across each router for every VRF. Each VRF has its own routing policy. With VRF-Lite, you don't have MPLS. You create separate virtual routing and forwarding tables (VRFs) in a router, but those are locally significant.

Hope this helps.

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