Augmenting data plane functionality with field programmable integrated circuits

Abstract

Some embodiments use one or more FPGAs and external memories associated with the FPGAs to implement large, hash-addressable tables for a data plane circuit. These embodiments configure at least one message processing stage of the DP circuit to store (1) a first plurality of records for matching with a set of data messages received by the DP circuit, and (2) a redirection record redirecting data messages that do not match the first plurality of records to a DP egress port associated with the memory circuit. These embodiments configure an external memory circuit to store a larger, second set of records for matching with redirected data messages received through the DP egress port associated with the memory circuit. This external memory circuit is a hash-addressable memory in some embodiments. To determine whether a redirected data message matches a record in the second set of record, the method of some embodiments configures an FPGA associated with the hash-addressable external memory to use a collision free hash process to generate a collision-free, hash address value from a set of attributes of the data message. This hash address value specifies an address in the external memory for the record in the second set of records to compare with the redirected data message.