US Patent 9755960 Session-aware service chaining within computer networks

Techniques are described for providing session-aware, stateful network services to subscriber packet flows. Devices within a service provider network direct subscriber packets along service chains. Each tunnel is established to direct traffic according a particular ordered set of network services for the corresponding service chain. An ingress device for the tunnels encapsulate the subscriber packets and embed opaque session cookies that each uniquely identifies a collection of packet flows of a subscriber session amongst other packet flows transported by a given service tunnel. Each service node need only identify the tunnel on which a tunnel packet was received and the session cookie embedded within the tunnel packet to uniquely associate the encapsulated subscriber packet with a subscriber session, without needing to further inspect the encapsulated subscriber packet, and to index or otherwise retrieve state and statistics required to enforce the network service the service nod is programmed to deliver.