Abstract: A configurable lookup table extension system including a plurality of lookup tables arranged in an internal memory, an external memory, and a flexible controller configured to couple at least one of the plurality of lookup tables to the external memory through a single memory interface is disclosed. Implementations of this system can support the flexible allocation of IP and MAC table entries so that a router/switch can flexibly support applications suited to a particular allocation. This approach provides an efficient scheme for extending multiple internal tables to external memory via a single external interface. Further, such extensibility is also programable to allow the size and number of external tables to be configured by software. This solution can provide the flexibility of customizing table sizes for different markets and/or customer requirements.

Abstract: A configurable lookup table system including a first controller coupled to a first lookup table and a second controller coupled to a second lookup table is disclosed. The first controller configures the first lookup table for a first type lookup, which can be a Layer 2 or Media Access Control (MAC) type. The second controller configures the second lookup table based on a mode determination. If in a first mode, the second lookup table can be configured for a second type lookup, which can be a Layer 3 or Internet Protocol (IP) type. If in a second mode, the second lookup table can be configured for the first type lookup. This approach provides an efficient scheme for controlling and using multiple internal lookup tables for a variety of product configurations.

Abstract: The invention relates to a crossbar switch controller including an input terminal configured to receive a set of service request signals from a set of virtual output queues each comprising a set of packets. The invention also includes a matrix circuit coupled to the input terminal and configured to represent the set of service request signals in the form of a matrix, wherein each service request signal is described by a row position M and a column position N. The invention further includes an output terminal configured to receive a portion of the set of packets during an epoch, an arbiter circuit configured to iteratively scan the matrix during the epoch and issue the set of grant signals to the virtual output queues to determine which service requests are granted, and an arbiter controller configured to initiate the arbiter circuit with an array of non-conflicting matrix elements.