Redback Networks Inc.

Renwei Li

Paul Terry

Thomas Ng

Henry Lee

Ronald Leonard Westfall

Peter Wai-Tong Kwong

Providing different levels of quality of service for different data flows being transported over a data link requires a very fast way to classify individual packets. Providing meaningful classification generally requires classifying data packets in several dimensions. A classification method represents a rule base as a hierarchy of linked tables and sequentially matches each parameter value in a packet signature against tables in the hierarchy. The method supports longest prefix matching and avoids time consuming backtracking by adding rules to the rule base.

Methods and apparatus for packet classification with multi-level data structure

Providing different levels of quality of service for different data flows being transported over a data link requires a very fast way to schedule individual packets for forwarding on the data link. The invention provides scheduling methods which give preference to higher priority packets while treating lower priority packets fairly. The methods can provide shorter latencies for higher priority packets than can many prior scheduling methods. The methods and apparatus of the invention are readily adaptable for use with scheduling rules provided in the form of hierarchical policy trees.

Packet scheduling methods and apparatus

Providing different levels of quality of service for different data flows being transported over a data link requires a very fast way to classify individual packets. Providing meaningful classification generally requires classifying data packets in several dimensions. A classification method processes multiple parameter values for a packet in parallel to obtain answer sets indicating which rules are matched by each parameter value. Answer indexes identify logical blocks in each answer set which contain TRUE values. The method performs an AND operation on the answer indexes to identify those blocks in the answer sets which could contain bits corresponding to matched rules. An AND operation is performed on the identified blocks to identify the particular rule matched by the packet. The classification method allows extremely fast wire speed packet classification.

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Renwei Li