Described herein are systems, methods, and apparatus for processing network packets in a computer network, including in particular the processing of subscriber traffic in a mobile network. According to the teachings hereof, distributed computing resources can be organized into a service platform to provide certain value-add services—such as deep packet inspection, transcoding, lawful intercept, or otherwise—using a service function chaining model. The platform may operate on traffic egressing or ingressing to a mobile network (or other target network) to the public Internet. The service platform can alternatively be deployed wholly or partially within a target network. Service function chains may be built dynamically based on configured platform policies, packet contents, computing resource status, load, network location, current network conditions, and the like. The teachings hereof support dynamic modification of service function chains, including service function chain re-ordering, service level modification, and dynamic insertion/deletion of service functions.