Advanced ethernet auto negotiation
US6580697B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Sep 21, 1999 |
| Grant date | Jun 17, 2003 |
| Priority date | — |
| Expiry date | Sep 21, 2019 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L49/55
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
A port on a network device engages in auto-negotiation on a network link during a first operational state to select a transmission mode, either half duplex or full duplex. If half duplex operation is selected, the port commences half duplex operation in a second operational state. During the second operational state, the link is monitored for an error condition indicating that another network device attached to the link may not be operating in a half duplex manner. This error condition includes the occurrence of excessive collisions or late collisions. When the error condition is detected, the port commences full duplex operation in a third operational state, based on the presumption that device at the other end of the link may be configured for fixed full duplex operation. If proper operation ensues, the port remains configured for full duplex transmission. Because the presumption may be incorrect, the link is monitored during the third operational state for a second error condition indicating that transmissions by the network device may be interfering with transmissions by the other network device. Examples of the second error condition include excessive frame check sequence erro…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.