Introduction to Virtual Routing and Forwarding (VRF) tables

Did you know that whenever you use Virtual Routing and Forwarding (VRF) tables in your network (be it on routers or on high-end switches), you’re actually benefitting from one of the MPLS/VPN technologies – VRFs were first introduced by Cisco to support the MPLS/VPN technology.

VRFs are pretty common in enterprise networks; the first half of my Enterprise MPLS/VPN Deployment webinar (register here) thus deals with VRFs, Multi-VRF (also known as VRF-Lite) and all sorts of VRF services, including VRF-aware NAT, per-VRF DHCP pools and interesting combinations of VRFs and GRE tunnels. Here’s the part where I explain what VRFs are as compared to VLANs:

1 comment:

  1. nice post Ivan, the biggest bugbear I find with VRF's is the lack of feature support, or if a feature is vrf-aware, it's only vrf-aware on a limited set of platforms.

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Ivan Pepelnjak, CCIE#1354, is the chief technology advisor for NIL Data Communications. He has been designing and implementing large-scale data communications networks as well as teaching and writing books about advanced technologies since 1990. See his full profile, contact him or follow @ioshints on Twitter.