Segment Routing over IPv6 (SRv6) defines several headend behaviors for how SRH (Segment Routing Headers) are added:

B. H.Insert — Inserts an SRH into an existing IPv6 packet.

C. H.Encaps — Encapsulates the original packet in a new IPv6 packet with an SRH.

D. H.Insert.Red — Performs insert behavior and reduces the payload for optimization.

A. H.Encaps.Red is not a defined SRv6 behavior — it’s an invalid option.

Exact Extract - Huawei SRv6 White Paper:

“H.Insert, H.Insert.Red, and H.Encaps are valid behaviors for injecting SRH. H.Encaps.Red is not defined in the SRv6 headend behavior set.”