Store-and-forward network switch using an embedded dram

Abstract

A store-and-forward network switch uses an embedded dynamic-random-access memory (DRAM) packet memory. An input port controller receiving a packet writes the packet to the embedded packet memory. The input port controller then sends a message to the output port over an internal token bus. The message includes the row address in the embedded packet memory where the packet was written and its length. The output port reads the message and reads the packet from the embedded memory at the row address before transmitting the packet to external media. Packets are stored at row boundaries so that DRAM page-mode cycles predominate. Only one packet is written to each DRAM row or page. Thus the column address is not sent between ports with the message sent over the token bus. A routing table can also be included in the embedded DRAM.