Cisco Technology, Inc.

John E Cavanaugh

Roy Michael Brooks

Alvaro E Retana

Paul M Quinn

Russell Ivan White

Mosaddaq Hussain Turabi

Bruce Eric Pinsky

Matthew Henry Birkner

An improved technique for distributing routing information that allows routes to be prioritized such that information associated with higher priority routes is sent in update messages ahead of information associated with lower priority routes, thereby enabling the higher priority routes to converge faster than the lower priority routes. In the preferred embodiment of the invention a route policy map that associates routes with priorities is defined. The policy map is then applied to the routes to prioritize the routes. Update messages are then generated using the priority information and the route information contained in the update messages is organized such that route information associated with higher priority routes is placed ahead of route information associated with lower priority routes.

Method for transmitting IP routes to prioritize convergence

In one embodiment, a method includes receiving topology data that indicates multiple communication links and multiple intermediate network nodes in communication based on the communication links. The intermediate network nodes include multiple leaf nodes that terminate communications and multiple transit nodes that facilitate the passage of information between leaf nodes. Aggregation point data is also received, which indicates all aggregation points on the intermediate network nodes. An aggregation point is an interface between a network node and a communication link, through which is output data that is a combination of data received through multiple different interfaces upstream of the interface. A set of paths is determined for which each path in the set connects a different pair of leaf nodes. A measure of aggregation is determined based on a number of aggregated paths of the set of paths. An aggregated path passes through an aggregation point.

Evaluation of network data aggregation

Conventional methods of addressing a Distributed Denial of Service attack include taking the target node offline, and routing all traffic to an alternate countermeasure, or 'sinkhole' router, therefore requiring substantial lag time to reconfigure the target router into the network. In a network, a system operator monitors a network for undesirable message traffic. Upon a notification of such undesirable message traffic, traffic is rerouted to a filter complex to separate undesirable traffic. The filter complex establishes an alternate route using a second communications protocol, and uses the alternate route to redirect the desirable message traffic to the target node. The use of the second protocol avoids conflict between the redirected desirable traffic and the original, or first, protocol which now performs the reroute. In this manner, the filter complex employs a second alternate communications protocol to reroute and redirect desirable message traffic to the target node while diverting undesirable message traffic, and therefore avoids widespread routing configuration changes by limiting the propagation breadth of the second protocol.

Methods and apparatus for network message traffic redirection

A method for testing congestion avoidance on a network by simulating transmission control protocol (TCP) streams. In one embodiment, one hundred TCP streams are initiated, wherein each TCP stream is operable to transmit data packets. A TCP stream comprises a current window size and a maximum window size. For each TCP stream, an unacknowledged traffic stream is initiated and directly tied to a referencing TCP stream and is controlled (e.g. rate limited) by the referenced TCP stream. This permits the companion unacknowledged traffic streams to be efficiently transmitted at high rates. In the event of congestion resulting in the dropping of packets from the traffic streams, each traffic stream will back off at the same rate. In one embodiment, an oversubscription factor is used to ensure network congestion causing the associated flow to decrease. The present invention provides for a method of testing congestion avoidance of a high speed network requiring only one processor.

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Raleigh, NC, United States of America

John E Cavanaugh