Full duplex flow control for ethernet networks
US6029202A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 23, 1997 |
| Grant date | Feb 22, 2000 |
| Priority date | — |
| Expiry date | Dec 23, 2017 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L49/351
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
CSMA/CD is used to implement flow control in a full-duplex Ethernet network in a lossless fashion. Uniquely identifiable flow control transmit on/off ("XON/XOFF") messages are transmitted, preferably during IPG, by a receiving station about to be congested to the transmitting station whose data output is to be controlled. The transmitting station physical layer receives and decodes these messages. If XOFF is recognized, the transmitting station continuously asserts CRS to its MAC layer at the MII, regardless of the prior CRS current state. CRS is continuously asserted until the receiving station transmits an XON flow control signal, indicating its ability to accept further data. During CRS assertion, the transmitting station defers transmission, e.g., is flow controlled. The MAC layer is slightly modified (but is still backward compatible with half-duplex networks) to provide separate transmit deferral receive data frame mechanisms using separate and independent input status signals, namely CRS and RX.sub.-- DV. CRS provides a carrierSense signal used for deferral within the MAC transmit process, and RX.sub.-- DV provides a receive.sub.-- carrierSense signal that frames data within…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.