Hierarchical SFC is a network architecture for implementing SFC the
chain with an ordered set of service functions which could be deployed
in multiple geographically dispersed networks. How to forward traffic
between networks in Hierarchical SFC is what the draft wants to
present. This document proposes a mapping-based forwarding method
with coordinated orchestration by the translation of H-SFC and I-SFC
to forward traffic between networks in Hierarchical SFC.