Inventors:
Marco Di Benedetto - Santa Clara CA, US
Mrinal Baruah - San Jose CA, US
Chengelpet Veeravalli Ramesh - San Jose CA, US
Alagu Annaamalai - Saratoga CA, US
Ramana Mellacheruvu - San Jose CA, US
Sridhar K. Aswathnarayan - San Jose CA, US
Hei Tao Fung - Santa Clara CA, US
Umesh Mahajan - Cupertino CA, US
Assignee:
Cisco Technology, Inc. - San Jose CA
International Classification:
G01R 31/08
Abstract:
A method and apparatus allows for continued operation of one or more applications running at a network device with reduced delay despite crashes or failures at that device. The network device includes two or more supervisor cards for running the applications and a plurality of line cards. According to the invention, one supervisor card is designated the active supervisor card and one supervisor card is designated the standby supervisor card. As changes in state and other operating conditions take place on the active supervisor events are generating for passing at least some of this information to the standby supervisor where it is stored. Following a crash or failure of the active supervisor card, the standby becomes the newly active supervisor card. The standby supervisor performs a consistency check with the line cards and resets those that fail the check. The standby supervisor also determines which data records and state information stored at the standby supervisor are valid, and begins running the applications loaded onto the device.