1. ClickCAM Using Click for Exploring Power Saving Schemes in Router Architectures Jonathan Ellithorpe, Laura Keys CS 252, Spring 2009

2. Motivation Energy Concerns $$ environmental Networking Impact operation costs hardware layout Where TCAM / SRAM fit in

3. Router – Hardware Model Power Hungry!

4. TCAMs (Ternary Content Addressable Memory)‏ Pros/Cons Uses Four stages precharge select lines match lines priority encoder

5. TCAM Configurations Pros / cons of smaller TCAMs Alternate Configurations Attempts to decrease power consumption sub-tables paging schemes + entry compression splitting TCAM into banks

6. Our Approach Reduce power consumption with small performance degradation Metrics Throughput (as a percentage of packets presented) Average Power Success attained by decreasing power by 2x the reduction in performance

7. Power-saving Schemes: Sleepy Banks If few number of unique entries accessed in a TCAM bank, turn off lesser used banks to save on static and leakage power Pros if traffic comes in bursts with large lapses, save on power Cons if traffic constantly hits in all banks, we either don't put any to sleep or else we frequently access DRAM

8. Sleepy Banks

9. Power-saving Schemes: Tuple Cache Use a smaller TCAM as a cache for low-power SDRAM Pros small TCAM is lower power and faster than larger one if we have small set of frequently accessed destinations, we could potentially save a lot of power Cons potential to pull from DRAM frequently if unique destination set is not small enough

10. Tuple Cache

11. Experiments Click timing notion UCSB's TCAM power model randomly generated workload represent different types of traffic

12. Flow-Based Workload Generator

13. Simulation Methodology

14. Results

15. Conclusions Hard to do power modeling in network hardware. Proprietary black boxes Tradeoff between power and performance is tricky! End zone hard to reach. Banking can help, but more banks => more waking and sleeping Workload also hard to estimate and has big impact on the power and performance tradeoff