VRF-lite (VRF's without MPLS)

nospam@example.com (Raymond P. Burkholder) — Fri, 22 Dec 2006 18:36:20 +0000

VRF-lite (Virtual Routing & Forwarding) is a handy construct for keeping data segregated within a network. It can be thought of as kind of a meta-VLAN thing.

At one customer site, who has a number of branch offices, has a Cisco Callmanager solution spanning those sites. Each site has an internet connection. Three sites are in a single metro area and are linked with metro-links as well as tunnels. A fourth site is in another country. The three sites are linked to the fourth site through IPSEC tunnels. Four different providers are used.

From a real usage perspective, there are six tunnels of consequence: the three tunnels from the metro area to the single site, and the three return tunnels from the single site to the three grouped metro sites. Each of those six tunnels can be categorized in terms of a voice quality metric.

The design puzzle was to come up with a mechanism to route data across a set of tunnels and route voice across a different set of tunnels, in order to make best use of measured delay, jitter, and loss metrics. Using Policy Based Routing (PBR) was one solution but was rejected due to its scaleability problems (ie, lack thereof).
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Raymond P. Burkholder - Things I Do - VRF

VRF-lite (VRF's without MPLS)