can provide the flexibility of customizing table sizes for different markets and or customer requirements application_number US 68778503 A description embodiments of the invention are described with reference to specific diagrams depicting system arrangements and methods those skilled in the art will recognize that the description is for illustration and to provide the best mode of practicing the invention the description is not meant to be limiting for example reference is made to several types of forwarding lookup tables including ip and mac types but the invention is applicable to other types of lookup tables as well further types of memory implementation including numbers of memory banks and the like merely provide example implementations and should not be construed as limiting referring now to fig2 a a depiction of an exemplary interface structure between a router switch and an external memory according to an embodiment is indicated by the general reference character 200 router switch 202 can interface through a single interface 206 to external memory 204 the single interface can include for example n data or dq signals also the same interface can include m address signals in one aspect of the invention n is 36 and m is 20 further the single interface can include a plurality of memory bank signals if the external memory is so organized referring now to fig2 b a relation between internal lookup tables and an external memory according to an embodiment is shown and indicated by the general reference character 250 router switch 252 can include forwarding engine 254 internal tables 256 and external memory interface 258 internal tables 256 can include a plurality of tables such as ip table 256 a mac table 256.