Cisco Technology, Inc.

Shyam Suri

John Harper

Himanshu H Shah

Chandrashekhar Appanna

Gargi Nalawade

Ruchi D Kapoor

Barry Friedman

Methods and apparatus for enabling a provider to perform a tracing procedure to determine the existence forwarding problems within its network are disclosed. According to one aspect of the present invention, a method for detecting a forwarding problem within an autonomous system includes initiating a message from a source node. The message is sent to a message destination that is an external address relative to the autonomous system. The method also includes forwarding the message from the source node along a path to the external address which includes an intermediate node and a destination node. The message is received on the destination node through a first path segment of the path. Finally, the message is removed from the path at the destination node, and a response that indicates that the intermediate node does not have a forwarding problem is sent along the first path segment to the source node.

Detection of forwarding problems for external prefixes

Methods and apparatus for efficiently enabling routing states to be recovered after a failover or during a software upgrade in a system which supports graceful restart and stateful switchover are disclosed. According to one aspect of the present invention, a method for restarting a network device which has a plurality of routers and is in communication with a first peer being arranged to support graceful restart and a second peer includes performing a graceful restart with respect to the first peer. A peer transparent failover is performed with respect to the second peer. The graceful restart and the peer transparent failover are performed in response to a failure associated with the network device.

Routing system and method for transparently rocovering routing states after a failover or during a software upgrade

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Fremont, CA, United States of America

Shyam Suri