Presented herein are techniques useful in a network comprising a plurality of network nodes each configured to apply one or more service functions to traffic that passes through the respective network nodes. A network node receives packets encapsulated in a service header that includes information defining a variable set of context headers stacked into an association of metadata that is relevant to one or more service functions within a service path comprised of one or more network nodes. The network node interprets a forwarding state and a next-hop network node for the service path from the service header, and determines a service action or associated metadata from the set of context headers.