Packet Content Filter for BGP FlowSpec

The BGP Flow Specification enables the distribution of traffic filter policies (traffic filters and actions) via BGP, facilitating DDoS traffic filtering. However, the traffic filter in FSv1 and FSv2 predominantly focuses on IP header fields, which may not adequately address volumetric DDoS attack traffic characterized by fixed patterns within the packet content. This document introduces a new flow specification filter type designed for packet content filtering. The match field includes ptype, otype, offset, content-length, content, and mask encoded in the Flowspec NLRI. This new filter aims to leverage network devices such as routers and switches to support controlled traffic handling, traffic optimization, and mitigation of simple volumetric DDoS attacks, reducing the overall processing cost of carrier networks.