Alcatel Internetworking, (Pe), Inc.

Other

Alcatel

Packet Engines Incorporated

James E Cathey

Timothy Scott Michels

Greg W Davis

Bernard N Daines

Jayasenan Sundara Ganesh

Jayansenan Sundara Ganesh

Parmajeet Singh

Michael Dale Helbling

A method of processing frames received at a sending port of a switching device for communication to a destination port includes storing in the switching device an offset value, a comparator value, and an expectant value; comparing information located at a position in a frame determined by the offset value with the comparator value to obtain an outcome; and processing the frame with the outcome. Processing the frame may include communicating the frame to a destination port or setting the priority of the frame. The offset and comparator values may be part of a filter that also includes an anchor value from which the offset value is measured and a mask value that masks the frame information before comparison with the comparator value. Where there are a multiple of filters in the switching device, the method may include combining the filter outcomes to obtain a filter group outcome; and processing the frame with the group outcome. Combining the filter outcomes may include logically combining their outcomes. The method may also include merging the outcome with frame forwarding information from another source; and processing the frame with the merged outcome. Apparatus in accordance with the invention practices these methods.

Content-based forwarding/filtering in a network switching device

A switching device for forwarding network traffic to a desired destination on a network, such as a telephone or computer network. The switching device includes multiple ports and uses a lookup table to determine which port to forward network traffic over. The lookup table includes network addresses that are maintained in ascending or descending order. The switching device includes multiple binary search engines coupled in series including one or more precursor binary search engines and a final stage binary search engine. Together, the binary search engines perform an N iteration binary search. Additionally, a single search engine can perform multiple concurrent searches so that source and destination addresses can be obtained simultaneously and without wasted memory cycles.

Network switching device with pipelined search engines

A switching device for forwarding network traffic to a desired destination on a network, such as a telephone or computer network. The switching device includes multiple ports and uses a lookup table containing lookup keys to determine which port to forward network traffic over. The lookup table includes disparate forwarding databases that contain database entries in different formats. For example, one forwarding databases may relate to MAC addresses, while another database relates to IP addresses. The disparate databases are maintained in a single lookup table and a binary search engine searches the table without regard to the database format. Like-kind database entries are grouped within the lookup table and the lookup table is maintained in sorted order by prepending format identification bits to the lookup keys. Memory availability for the disparate databases can be dynamically changed allowing customization for a particular user application. Consequently, memory can be efficiently used and reallocated if needed.

Network switching device with disparate database formats

A switching device for forwarding network traffic to a desired destination on a network, such as a telephone or computer network. The switching device includes multiple ports and uses a lookup table to determine which port to forward network traffic over. The lookup table includes network addresses that are maintained in ascending or descending order. The lookup table also includes network address that differ in length. Fictitious network addresses may also be added to the lookup table to expedite searches in the lookup table. The fictitious network addresses are used in conjunction with a comparison field stored in the lookup table. The comparison field allows network addresses and collapsed network addresses (which represent groups of network addresses) to be stored within the same table. The collapsed network addresses allows for a reduction of overall lookup table size, thereby increasing the speed while reducing the cost of the switching device.

Method and apparatus for forwarding network traffic

Network switching device with concurrent key lookups

Growing community of inventors

Greenacres, WA, United States of America

James E Cathey