Carrier extension for gigabit/second ethernet networks operable up to at least 200 m distances
US5940401A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 10, 1997 |
| Grant date | Aug 17, 1999 |
| Priority date | — |
| Expiry date | Jan 10, 2017 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L12/413
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
Transmission rates of 1 Gb/sec. at up to at least 200 m diameter distances are achieved in an Ethernet environment by functionally decoupling frame size to network roundtrip time. This decoupling is achieved by extending the duration of the minimum size event to exceed the network roundtrip time. This extension of the carrier event is made without extending the data field and without altering the frame check sequence. Code implementing the media access control layer and reconciliation layer at the transmitting and receiving end of the network is modified such that at 1 Gb/sec. half-duplex, non-data symbols are appended to the end of short packet frames. The collision window is extended to include these symbols, which extension symbols are also included in fragment discard calculations. The extension is removed, however, before checking the frame check sequence, and before passing the frame to logical link and control. In a switched environment, the extension is not propagated to network links operating at less than 1000 Mb/sec. flowrates, which feature makes the invention backward compatible with existing slower transmission rate Ethernet networks. In full-duplex Ethernet environme…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.