About SRTE Over Default VRF
The SRTE Over Default VRF feature allows you to incorporate segment routing traffic engineering to achieve the traffic steering benefits in your network. The SRTE provides increased scalability while using BGP for routing in large-scale data centers (DC).
The SRTE Over Default VRF feature uses the route color that exists as an extended community attribute and is represented by a number as the base for traffic steering. Based on the color, plane separation is achieved, and an SR policy is created to carry the traffic. Furthermore, based on the color, the DC is divided into different planes. The applications are configured to use each plane to only route through a specific plane and steer traffic to appropriate destinations.
Plane separation has the following advantages:
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One flow does not affect the other flow.
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Large and small flows are separated into different planes.
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Fault isolation for better debuggability: Fault in one plane does not affect the other planes. For example, if a network fault occurs in one plane, only the applications in that plane are affected, but the applications in the rest of the planes are not impacted. Additionally, the fault can be isolated and troubleshooted in isolation.
The following example explains the SRTE Over Default VRF feature with an illustration.
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For BGP, node A is the ingress router and node D is the egress router. D is also the next-hop.
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For SRTE, node A is the SRTE headend, node D is the endpoint for the policy.
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Route prefix 1 is configured to use the blue plane, and route 2 is configured to use the red plane.
The blue traffic is appended with instructions to steer the traffic through node B and node C, and the red traffic is appended with instruction to steer traffic through node E and node F. In summary, the traffic is handled based on the color of the advertisement, that is, the prefix that was advertised earlier.