I/O efficient dynamic data structures for longest prefix queries

We present an efficient data structure for finding the longest prefix of a query string q in a dynamic database of strings.When the database strings are prefixes of IP-addresses then this is the IP-lookup problem. Our data structure is I/O efficient. It supports a query with a string q using O(logB(n) + |q| B ) I/O operations, where B is the size of a disk block. It also supports an insertion and a deletion of a string q with the same number of I/Os. The data structure requires O(n/B) blocks, and the running time for each operation is O(B logB(n) + |q|).