Complex name constitution plus huge-sized name routing table makes wire speed name lookup a challenging task in Named Data Networking. To overcome this challenge, we propose two techniques to significantly speed up the lookup process. First, we look up name prefixes in an order based on the distribution of prefix length in the forwarding table, which can find the longest match much faster than the linear search of current prototype CCNx. The search order can be dynamically adjusted as the forwarding table changes. Second, we propose a new near-perfect hash table data structure that combines many small sparse perfect hash tables into a larger dense one while keeping the worst-case access time of 0( 1) and supporting fast update. Also the hash table stores the signature of a key instead of the key itself, which further improves lookup speed and reduces memory use.

Different from the IP-based routers, Named Data Networking routers forward packets by content names, which consist of characters and have variable and unbounded length. This kind of complex name constitution plus the huge-sized name routing table makes wire speed name lookup an extremely challenging task. Greedy name lookup mechanism is proposed to speed up name lookup by dynamically adjusting the search path against the changes of the prefix table. Meanwhile, we elaborate a string-oriented perfect hash table to reduce memory consumption which stores the signature of the key in the entry instead of the key itself. Extensive experimental results on a commodity PC server with 3 million name prefix entries demonstrate that greedy name lookup mechanism achieves 57.14 million searches per second using only 72.95 MB memory.

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.

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