Identifying network devices having specified traits using a multi-level hierarchical data structure. Bloom filters representing traits of network devices are received and their bit vectors are decomposed into successive bytes. For each byte except the last one, memory for storing a pointer to memory on the next level is allocated on the level corresponding to the byte. The pointer storage is labeled by the value of the next byte. A pointer to the allocated memory is stored in the pointer storage on the previous level that was labeled by the value of the current byte. For the last byte, memory for storing references to network devices is allocated on the last level. A pointer to the allocated memory is stored in the pointer storage on the second-to-last level that was labeled by the value of the last byte. A reference to the network device is stored in the allocated memory.