Runt packet filter
US4679193A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 14, 1985 |
| Grant date | Jul 7, 1987 |
| Priority date | — |
| Expiry date | Nov 14, 2005 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L12/413
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
Provided is a circuit for preventing local area network packets shorter than a predetermined bit length from being received by a local area network coprocessor. Serial data which would otherwise be received by the coprocessor is delayed by a data-shift register of predetermined bit length. Simultaneously, a carrier-sense-signal, which alerts the coprocessor that serial data is ready to be received, is modified by a carrier-sense-signal regeneration circuit. If the carrier-sense-signal is detected true by the regeneration circuit for a number of clock cycles equal to the number of bits in the data-shift register, then the carrier-sense-signal is delivered to the coprocessor and the data in the data-shift register is received by the coprocessor. Once the carrier-sense signal goes false, the regeneration circuit continues to deliver the carrier-sense-signal until the data-shift register empties.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.