3. Service Route Steering (服务路由引流)

Service route steering 将带 color 的 service route 流量映射到满足相同 intent 的 color-aware path. Ingress PE 或 ASBR 收到来自 egress PE 的 colored service route 后, 根据 Color-EC, SRv6 locator 或 local policy 选择 BGP CAR path, SR Policy, IGP Flexible Algorithm path 或其他 transport mechanism.

对 MPLS 和 SR-MPLS, service route 可解析到携带 label 或 label index 的 BGP CAR route. 对 SRv6, service route 可解析到 intent-specific locator 或 SRv6 SID. 当不存在对应 color-aware path 时, local policy MAY 回退到 best-effort 或 color-unaware route.

Steering 与 resolution 不同: steering 是 service traffic 到 transport path 的映射, resolution 是 BGP CAR route 到 next-hop color-aware path 的映射.