The document discusses service function chaining (SFC) using Segment Routing over IPv6 (SRv6), detailing two types of service functions: SR-aware and SR-unaware. It explains how SRv6 facilitates the creation of composite network services by assigning segment identifiers to service functions and sequencing them in a segment list. Examples of Linux-based network nodes show the routing configurations and behaviors of SR-aware service functions in traffic steering.