[54] ADDRESS RECOGNITION ENGINE WITH LOOK-UP DATABASE FOR STORING NETWORK INFORMATION
[75] Inventors: Andrew Walton, Reading, England;
Una M. Quinlan, Dublin, Ireland;
Stewart F. Bryant, Redhill, England;
Michael J. Seaman, San Jose, Calif.;
John Rigby, Reading, England;
Fearghal Morgan, Moycullen; Joseph
O'Callaghan, Glounthaune, both of
Ireland
[73] Assignee: Digital Equipment Corporation,
Maynard, Mass.
[21] Appl. No.: 819,490
[22] Filed: Jan. 10,1992
[51] Int. CI.6 G06F 17/30
[52] U.S. CI 395/600; 364/251.6; 364/255.3;
364/255.7; 364/963.3; 364/DIG. 1; 395/412
[58] Field of Search 395/200, 275,
395/425, 600, 400
[56] References Cited
U.S. PATENT DOCUMENTS
The present invention is directed to an address recognition apparatus including an address recognition engine coupled to a look-up database. The look-up database is arranged to store network information relating to network addresses. The look-up database includes a primary database and a secondary database. The address recognition engine accepts as an input a network address for which network information is required. The address recognition engine uses the network address as an index to the primary database. The primary database comprises a multiway tree node structure (TRIE) arranged for traversal of the nodes as a function of preselected segments of the network address and in a fixed sequence of the segments to locate a pointer to an entry in the secondary database. The entry in the secondary database pointed to by the primary database pointer contains the network information corresponding to the network address. The address recognition engine includes a table for storing a plurality of database specifiers. Each of the database specifiers contains control information for the traversal of the primary and secondary databases. In addition, each of the nodes in the primary database and each of the entries in the secondary database is provided with control data structures that are programmable to control the traversal of the database.
