A fault-tolerant bloom filter for deep packet inspection

Bloom filters can be used for various networking applications to inspect network packet payload to search for predefined signature strings. Hardware-based Bloom filters have drawn a great attention due to the fact that they provide constant lookup times at the cost of small false positives. A fault in Bloom filters, however may render the system unable to function correctly since no false negatives cannot be guaranteed. In this paper we present a fault tolerant Bloom filter which tolerates faults in such a way that no false negatives can be guaranteed. The proposed architecture is simple enough to be implemented without any significant hardware overhead. Moreover, fault detection and recovery can be made during normal operation with negligible time overhead.