Stacking metadata contexts for service chains

An apparatus comprising:

• a network interface unit configured to enable communications over a network, the 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 memory;
• and
• a processor coupled to the network interface unit and the memory, wherein the processor is configured to:
• receive packets encapsulated in a service header that includes a first set of context headers with metadata that is relevant to one or more service functions within a service path comprised of one or more network nodes;
• interpret a forwarding state and a next-hop network node for the service path from the service header, and determine a service action or associated metadata from the first set of context headers;
• and
• rewrite the service header with a second set of context headers.

One or more non-transitory computer readable storage media encoded with software comprising computer executable instructions and when the software is executed operable to:

• receive, at a network node, packets encapsulated in a service header that includes a first set of context headers with metadata that is relevant to one or more service functions within a service path comprised of one or more network nodes;
• interpret a forwarding state and a next-hop network node for the service path from the service header, and determine a service action or associated metadata from the first set of context headers;
• and
• rewrite the service header with a second set of context headers.