Low-Power Network-Packet-Processing Architecture Using Process-Learning Cache for High-End Backbone Router

Michitaka OKUNO  Shin-ichi ISHIDA  Hiroaki NISHI  

IEICE TRANSACTIONS on Electronics   Vol.E88-C   No.4   pp.536-543
Publication Date: 2005/04/01
Online ISSN: 
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Section on Low-Power LSI and Low-Power IP)
Category: Digital
router,  Ethernet,  packet-processing engine,  network processor,  cache-based packet-processing engine,  

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A novel cache-based packet-processing-engine (PPE) architecture that achieves low-power consumption and high packet-processing throughput by exploiting the nature of network traffic is proposed. This architecture consists of a processing-unit array and a bit-stream manipulation path called a burst stream path (BSP) that has a special cache mechanism called a process-learning cache (PLC). Network packets, which have the same information in their header, appear repeatedly over a short time. By exploiting that nature, the PLC memorizes the packet-processing method with all results (i. e. , table lookups), and applies it to other packets. The PLC enables most packets to skip the execution at the processing-unit array, which consumes high power. As a practical implementation of the cache-based PPE architecture, P-Gear was designed. In particular, P-Gear was compared with a conventional PPE in terms of silicon die size and power consumption. According to this comparison, in the case of current 0.13-µm CMOS process technology, P-Gear can achieve 100-Gbps (gigabit per second) packet-processing throughput with only 36.5% of the die size and 32.8% of the power consumption required by the conventional PPE. Configurations of both architectures for the 1- to 100-Gbps throughput range were also analyzed. In the throughput range of 10-Gbps or more, P-Gear can achieve the target throughput in a smaller die size than the conventional PPE. And for the whole throughput range, P-Gear can achieve a target throughput at lower power than the conventional PPE.