Patent ID: 9246799
Filing Date: 2016-01-26
CPC Classification: H04L

Claim Text:
1. A method comprising: in a network comprising a plurality of network nodes each configured to apply a service function to traffic that passes through the respective network node in addition to forwarding the traffic, receiving a packet at a network node, the packet having a network service header that includes service path identifier information that identifies a service chain comprised of one or more service functions and order of service functions to be applied to a forward path of traffic matching classification criteria, and context information indicating whether a service function applied at a corresponding network node is stateful and thus a reverse path of traffic matching the classification criteria needs to be directed to the network node at which the stateful service function is applied; the network node applying a service function to a packet that is forwarded to it in the forward path; the network node determining whether the service function that it applies is stateful; when the network node determines that the service function it applies is stateful, updating the context information in the network service header to indicate that the service function applied at the network node is stateful and that traffic for a reverse path matching the classification criteria is to be returned to the network node; forwarding the packet to at least one of a next service node or towards a destination network device; receiving, at the network node, a packet that is forwarded in the reverse path; and applying a further service function to the packet in response to the determining that the service function applied to the packet forwarded to the network node in the forward path is stateful.