Modeling TCAM power for next generation network devices

Applications in computer networks often require high throughput access to large data structures for lookup and classification. Many advanced algorithms exist to speed these search primitives on network processors, general purpose machines, and even custom ASICs. However, supporting these applications with standard memories requires very careful analysis of access patterns, and achieving worst case performance can be quite difficult and complex. A simple solution is often possible if a Ternary CAM (content addressable memory) is used to perform a fully parallel search across the entire data set. Unfortunately, this parallelism means that large portions of the chip are switching during each cycle, causing large amounts of power to be consumed. While researchers have begun to explore new ways of managing the power consumption, quantifying design alternatives is difficult due to a lack of available models. In this paper, we examine the structure inside a modern TCAM and present a simple, yet accurate, power model. We present techniques to estimate the dynamic power consumption of a large TCAM. We validate the model using industrial TCAM datasheets and prior published works. We present an extensive analysis of the model by varying various architectural parameters. We also describe how new network algorithms have the potential to address the growing problem of power management in next-generation network devices.