Network device with local timing systems for automatic selection between redundant, synchronous central timing systems
US6658579B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Jul 11, 2000 |
| Grant date | Dec 2, 2003 |
| Priority date | — |
| Expiry date | Apr 5, 2022 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L69/18
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
The present invention provides a network device including redundant, synchronous central timing subsystems (CTSs) and local timing subsystems (LTSs) including control circuits for automatically selecting between reference signals from both central timing subsystems. Automatically selecting between reference timing signals allows each LTS to quickly switchover from a failing or failed reference timing signal to a good reference timing signal. Quick switchovers prevent data corruption errors that may result during slow switchovers where a failing or failed reference signal is used for a longer period of time prior to the switch over. In addition, since each LTS independently monitors its received reference timing signals, a problem on one reference timing signal is quickly detected by the LTS and the LTS switches over to the good reference timing signal regardless of whether any other LTSs detect a problem with their received reference timing signals. Consequently, each LTS that detects a problem with a timing reference signal may immediately switch over to a good reference signal and not be forced to wait for all LTSs to be switched over.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.