Method and apparatus for longest prefix matching based on a trie
US7539153B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Sep 30, 2008 |
| Grant date | May 26, 2009 |
| Priority date | — |
| Expiry date | Sep 30, 2028 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L45/74591
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
The present invention discloses a method and apparatus for longest prefix matching. The method includes (A) reading a current-level trie node (TNODE) in the trie, (B) determining whether an offset field of the TNODE indicates that a matched prefix exists in an upper level node and, if so, adding the offset field of the TNODE to a pointer that points to a leaf array in the upper level node, updating a current best match pointer with the computation result and executing block (C), otherwise, executing block (C), (C) determining whether the TNODE has a child node according to a child bitmap, when it is determined that a branch flag of the TNODE matches a corresponding bit of a search keyword, and (D) when it is determined that the TNODE has no child node, reading the internal bitmap of the TNODE, computing a longest matched prefix in the TNODE according to the internal bitmap and a pointer that points to a leaf array in the TNODE, updating the current best match pointer with the computation result, and computing an address of a leaf node (LNODE) associated with the current best match pointer.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.