Fast scaleable methods and devices for layer four switching
US6212184A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 15, 1998 |
| Grant date | Apr 3, 2001 |
| Priority date | — |
| Expiry date | Jul 15, 2018 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L49/3009
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
Fast, scalable methods and devices are provided for layer four switching in a router as might be found in the Internet. In a first method, a grid of tries, which are binary branching trees, is constructed from the set of routing filters. The grid includes a dest-trie and a number of source tries. To avoid memory blowup, each filter is stored in exactly one trie. The tries are traversed to find the lowest cost routing. Switch pointers are used to improve the search cost. In an extension of this method, hash tables may be constructed that point to grid-of-tries structures. The hash tables may be used to handle combinations of port fields and protocol fields. Another method is based on hashing, in which searches for lowest cost matching filters take place in bit length tuple space. Rectangle searching with precomputation and markers are used to eliminate a whole column of tuple space when a match occurs, and to eliminate the rest of a row when no match is found. Various optimizations of these methods are also provided. A router incorporating memory and processors implementing these methods is capable of rapid, selective switching of data packets on various types of networks, and is pa…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.