Specialized communications processor for layered protocols
US4991133A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 7, 1988 |
| Grant date | Feb 5, 1991 |
| Priority date | — |
| Expiry date | Oct 7, 2008 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L69/12
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
A special purpose communications protocol processor (CPP) provides more efficient processing of layered communications protocols--e.g. SNA (Systems Network Architecture) and OSI (Open Systems Interconnection)--than contemporary general purpose processors, permitting hitherto unavailable operations relative to high speed communication links. The CPP contains special-purpose circuits dedicated to quick performance (e.g. single machine cycle execution) of functions needed to process header and frame information, such functions and information being of the sort repeatedly encountered in all protocol layers, and uses instructions architected to operate these circuits. The header processing functions given special treatment in this manner include priority branch determination functions, register bit reshaping (rearranging) functions, and instruction address processing functions. Frame processing functions so handled include CRC (cyclic redundancy check) computations, bit insertion/deletion operations and special character detection operations.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.