Cisco Technology, Inc.

Christian E Hopps

David Delano Ward

Reshad Rahman

David P Toscano

Jean-Marc Simard

Stefano Benedetto Previdi

Anthony Joseph Li

Abhay Kumar Roy

Derek Man-Kit Yeung

Lester C Ginsberg

Nair Venugopal

Derek M Yeung

In one embodiment, a method generally includes establishing a routing protocol peer relationship and a Bidirectional Forwarding Detection (BFD) session with a neighbor node, receiving a DOWN BFD event signal from the neighbor node, and maintaining a routing protocol adjacency down state following successful exchange of routing protocol packets with the neighbor node. An apparatus for maintaining protocol adjacency state with a forwarding failure is also disclosed.

Maintaining protocol adjacency state with forwarding failure

A system and method for bidirectional forwarding detection (BFD) rate-limiting and automatic BFD session activation includes tracking a total bidirectional forwarding detection (BFD) packet rate for a line card (LC) of the node, and rejecting operations associated with creation of a new BFD session that would cause the total BFD packet rate to exceed a predetermined maximum rate. The new BFD session is stored in a state on the node and the operations of the new BFD session are automatically retried at a time when doing so would not exceed the predetermined maximum rate.

BFD rate-limiting and automatic session activation

A technique efficiently avoids transient routing disturbances in link state routing protocols with fragmented link state packets (LSPs) in a computer network. According to the novel technique, a link state router (LSR) specifies which of two or more links are to be advertised in each of two or more corresponding LSP fragments. The LSR advertises the states of the specified links in the corresponding LSP fragments to one or more other LSRs. In other words, each link of the LSR is assigned to a particular LSP fragment, and the state of the link is always to be advertised in that particular LSP fragment (i.e., no fragment wrapping). Upon receiving the LSP fragments, the other LSRs may update the correct link states based on the individual LSP fragments, i.e., without transient routing disturbances caused by fragment wrapping.

Technique for efficiently avoiding transient routing disturbances in link state routing protocols with link state packet fragmentation

A networking device such as a router may include, in one embodiment, a database storing a plurality of link state entries, and a cache operatively coupled with the database, the cache storing entries relating to the link state entries of the database. The networking device may also include a module for sending, over a network, packets including link state data, the module operatively coupled with the cache. In one example, the module accesses the cache to create one or more packets including link state data. Embodiments of the invention may be used for forming CSNP packets (complete sequence number packets) without the need for having to repeatedly walking a link state database in order to form the CNSP packets.

CSNP cache for efficient periodic CSNP in a router

A system and method for bidirectional forwarding detection (BFD) rate-limiting and automatic BFD session activation includes tracking a total bidirectional forwarding detection (BFD) packet rate for a line card (LC) of the node, and rejecting operations associated with creation of a new BFD session that would cause the total BFD packet rate to exceed a predetermined maximum rate. The new BFD session is stored in a state on the node and the operations of the new BFD session are automatically retried at a time when doing so would not exceed the predetermined maximum rate. It is emphasized that this abstract is provided to comply with the rules requiring an abstract that will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims.

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San Francisco, CA, United States of America

Christian E Hopps