As the network infrastructure has been consuming more and more power, various schemes have been proposed to improve the power efficiency of network devices. Many schemes put links to sleep when idle and wake them up when needed. A presumption in these schemes, though, is that router's line cards can be waken up very quickly. However, through systematic measurement of a major vendor's high-end routers, we find that it takes minutes to get a line card ready under the current design. To address this issue, we propose a new line card design that 1) keeps the host processor in a line card standby, which only consumes a small fraction of power but will save considerable wakeup time, and 2) downloads a slim slot of popular prefixes with higher priority, so that the line card will be ready for forwarding most of the traffic much earlier. We design algorithms as well as architecture that ensure fast and correct longest prefix match during prioritized routing prefix download. Experiments on an FPGA-based prototype show that the customized hardware can be ready to forward packets in 127.27 ms, which is 0.3% of the time the original design takes. This can better support numerous power-saving schemes based on the sleep/wakeup mechanism.

Updating rules in the flow tables of SDN switches are complex and time-consuming. Therefore, we propose a cache-based scheme (named FlowShadow) to improve the packet processing performance and keep continuous operating while updating rules in the flow tables. FlowShadow caches the microflows in the hash table to build a fast path for packet processing. By leveraging the Action Table, FlowShadow achieves update consistency and good update performance. In order to examine the reliability, validity, utility and scalability of FlowShadow, we implement FlowShadow on the Open VSwitch and conduct numerous experiments with different settings to measure the performance of FlowShadow. The experimental results demonstrate that FlowShadow achieves a lookup speed of 75 million packets per second on a commodity PC under the real backbone traces; the system with FlowShadow speeds up 3.4× times of the original Open VSwitch.

Bloom filters are widely used in many network applications but the high computation cost limits the system performance. In this paper, we introduce a new variation of Bloom filter named One-Hashing Bloom Filter (OHBF) to solve the problem. OHBF requires only one base hash function plus a few simple operations to implement a Bloom filter. While keeping nearly the same theoretical false positive ratio as an ideal Bloom filter, OHBF significantly reduces the hash computation overhead. We show that the false positive performance of a standard Bloom filter implementation strongly relies on the selection of hash functions, even if these hash functions are considered good. In contrast, OHBF presents consistently better performance with a proven mathematical foundation. OHBF is ideal for high throughput and low latency applications. As OHBF is a fundamental technique in Bloom filter theory, it can be applied to many other Bloom filter variations, such as Counting Bloom Filter and Space-Code Bloom Filter.

As the network infrastructure has been consuming more and more power, various schemes have been proposed to improve power efficiency of network devices. Many schemes put links to sleep when idle and wake them up when needed. A presumption in these schemes, though, is that router's line cards can be waken up quickly. However, through systematic measurement of a major vender's high-end router, we find that it takes minutes to get a line card ready under the current implementation. To address this issue, we propose a new line card design that (1) keeps the host processor in a line card always up, which only consumes a small fraction of power, and (2) downloads a slim slot of popular prefixes with higher priority, so that the line card will be ready for forwarding most of the traffic much earlier. We design algorithms that ensure fast and correct longest prefix match lookup during prioritized routing prefix download. Experiments on real hardware show that the wakeup time can be reduced to 127.27ms, which is 0.3% of the original line card wakeup time, well supporting many power-saving schemes.