Byte-wide repeat filter
US5128935A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 8, 1989 |
| Grant date | Jul 7, 1992 |
| Priority date | — |
| Expiry date | Nov 8, 2009 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L12/433
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
In an FDDI token ring network, a repeat filter that treats FDDI Set and Reset symbols occurring in a frame prior to an End Delimiter symbol as a violation and does not repeat these symbols onto the FDDI ring. In addition to the three states described in the FDDI repeat filter standard for a byte-wide implementation, a repeat filter in accordance with the present invention includes a fourth END state. The presence of this END state allows the REPEAT state to be restricted such that it treats bytes within a frame with either symbol of the byte being either a Set or Reset symbol as a violation and a Halt byte is transmitted onto the ring; the repeat filter then enters the Halt state. In addition, the repeat filter is also responsive to "mixed" bytes that consist of an FDDI data symbol and an FDDI control symbol. If the mixed byte is a data symbol followed by an End Delimiter symbol, then the repeat filter transmits an FDDI zero symbol followed by an End Delimiter symbol and enters the END state; if the mixed byte consists of a data symbol followed by an Idle symbol, then the repeat filter transmits an Idle byte and enters the Idle state.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.