Cisco Technology, Inc.

Muhammad Ahmed Moizuddin

Mukhtiar Shaikh

Himanshu H Shah

Peter Psenak

Gargi Nalawade

Sina Mirtorabi

Muhammad Sarosh Niazi

A novel technique is provided for preventing routing loops by disseminating Border Gateway Protocol (BGP) attribute information in an Open Shortest Path First (OSPF) configured network. Specifically, a new OSPF sub-type-length-value (TLV) is introduced for transporting a conventional BGP autonomous system (AS) path attribute through the OSPF-configured network. Like the BGP AS-path attribute, the new OSPF AS-path sub-TLV is configured to store a set of AS numbers corresponding to the AS path of one or more advertised routes. Thus, when a network device receives an OSPF link-state advertisement (LSA) containing the novel AS-path sub-TLV, the network device determines whether it resides in an autonomous system whose AS number is stored in the sub-TLV. If so, the network device does not install the LSA's advertised routes in its link-state database since the routes, if installed, could result in routing loops.

Technique for preventing routing loops by disseminating BGP attribute information in an OSPF-configured network

Methods and systems for identifying instability or a loop in a network. In one method, a first BPDU message is received at a switch indicating a topology change. The message includes a bridge identifier identifying a network device originating the first BPDU message. A second BPDU is generated at the switch and includes the bridge identifier identifying the network device originating the first BPDU message. The method further includes transmitting the second BPDU message indicating the topology change from the switch.

Method and system for identifying instability or a spanning tree protocol loop in a network

A method for border nodes using the Border Gateway Protocol to advertise path updates to peer nodes in other domains involves calculating the update interval for each advertisement of an update of the same path to the same peer and advertising the update when the interval has expired. The update interval is the sum of the standard update interval and the unexpired portions of update intervals applied to previous unadvertised updates.

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San Jose, CA, United States of America

Muhammad Ahmed Moizuddin