Name prefix matching using bloom filter pre-searching for content centric network

• This paper proposes a new approach for the longest name matching used in FIB lookups in CCN routers.
• The proposed approach uses a hashing-based name prefix trie (NPT) and a Bloom filter.
• An off-chip table storing the NPT is accessed depending on the result of the Bloom filter querying.
• By pre-searching the on-chip Bloom filter, the number of off-chip hash table accesses is reduced.
• The proposed approach can provide the output face less than a single node access on average.

As a new networking paradigm for future Internet, content centric networking (CCN) technology provides a contents-oriented communication infrastructure for the rapidly increasing amount of data traffic. For the successful realization of CCN, it is essential to design an efficient forwarding engine that performs high-speed name lookup. This paper proposes the use of a hashing-based name prefix trie and a Bloom filter. In the proposed approach, an off-chip hash table storing the nodes of the name prefix trie is only accessed when the Bloom filter states that the node under querying exists in the trie. In accessing the node depending on the result of the Bloom filter, we propose two algorithms that have different strategies. The first algorithm accesses the trie node for every positive result of the Bloom filter, while the second algorithm first attempts to determine the longest matching length using Bloom filter queries. Trie nodes are accessed from the possible longest length, and tracked back if there is no match. Simulation results show that the proposed approach can provide the output face of each input name, with a single node access on average and with two node accesses in the worst-case using a reasonable size of a Bloom filter.

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