Patent ID: 7269133
Filing Date: 2007-09-11
Classification: H04L

Abstract:
1. A method of highly-available Intermediate System to Intermediate System (HA IS-IS) routing in a network, comprising the steps of: creating a backup IS-IS instance running on a Master Control Processor (MCP) platform; creating local link state PDU (LSP) initially synchronizing the state of said backup IS-IS instance with the state of an active IS-IS instance running separately on said Master Control Processor (MCP) platform and linked with said backup IS-IS instance; dynamically synchronizing the ongoing state of said backup IS-IS instance with said active IS-IS instance using a combination of explicit message updates from said active IS-IS instance to said backup IS-IS instance together with a message flow-through mechanism; and in the event of protected fail-over of said active IS-IS instance, then seamlessly recovering from said fail-over without reconfiguring or interrupting traffic among peer routers in said network,