Described are a system and computer-implemented method for searching and updating a routing table for forwarding IP packets through a communications network. Records containing IP address prefixes are organized in a binary tree data structure. When inserting a new record, one of the records in the binary tree data structure is identified as an enclosing record having an associated record data range that encloses record data of the new record. An enclosing pointer of the new record is set to point to the identified enclosing record. When searching for a longest matching prefix for a destination IP address, the binary tree data structure is traversed and one of the records in the binary tree data structure is identified as an enclosing record, which is returned as the longest matching prefix.