Cisco Technology, Inc.

Punit Bhargava

Sriram Krishnan

Rina Panigrahy

A method, computer program product, system and apparatus are presented for reducing wasted bandwidth due to supercasting multicast cells through a router switch fabric. In one embodiment of the present invention, signatures of a switch fabric destination address are generated and compared. A signature is an information-rich representation of the fabric destination address that is generated using the fabric destination address. Therefore, supercasting can be minimized by combining fabric destination addresses with like signatures. Aspects of the present invention include generating the signatures using random permutation maps of the set of switch fabric ports or determining intersections of a fabric destination address with a selection of subsets of the switch fabric ports. Signature-based solutions for supercast minimization can be performed in a time-efficient manner and be implemented online, while solutions that can generate a more optimal solution but may take a longer time to perform, such as row-clustering, can be implemented off-line. A further aspect of the invention, incorporates an off-line row-clustering supercast minimization method with an on-line signature-based supercast minimization method.

Constant time signature methods for scalable and bandwidth-efficient multicast

A method, system, computer program product, and apparatus for reducing wasted bandwidth due to supercasting multicast cells through a router switch fabric is presented. A multicast destination address is compared to each destination address in a label-to-destination address table (LTDT) to determine the wasted bandwidth due to incorporating any additional switch fabric ports designated by the new destination address with beyond the switch fabric ports designated for each LTDT entry. Also considered is the amount of traffic experienced by each LTDT entry and that expected for the new destination address.

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Sunnyvale, CA, United States of America

Punit Bhargava