A Distributed TCAM Coprocessor Architecture for Integrated Policy Filtering and Content Filtering

Policy Filtering (PF) and Content Filtering (CF) are two important tasks in packet forwarding of today´s Internet. It is both technologically and economically important to develop integrated solutions for executing both tasks to reduce cost. In this paper, we propose a distributed Ternary Content Addressable Memory (TCAM) coprocessor architecture to allow fast and integrated PF and CF. Due to significant requirement diversities in both lookup load and storage load between PF and CF, the integrated solution exploits the complementary characteristics of the two tasks and well balances both the lookup load and storage load among TCAMs. A prefix filtering based CF algorithm is designed to reduce the lookup load and a novel cache mechanism is developed to dynamically handle the lookups from overloaded TCAMs. Simulations based on real-world traffic traces show that the proposed solution can match 10Gbps line rate for executing both PF and CF with the similar costs as CF task only.