Address modification within a switching device in a packet-switched network

A multiport network device comprising:

• a receiver configured to receive data frames from a network, each of the data frames having header information that includes at least a source field indicating a source of the data frame and a destination field indicating an intended destination address for the data frame;
• a transmitter configured to transmit the data frames to the network through a plurality of transmit ports;
• internal rules checking logic coupled to an output of the receiver, the internal rules checking logic receiving the header information relating to the data frames received by the receiver and, based on the header information, generating a forwarding descriptor that identifies the transmit ports and an associated new intended destination address for each of the data frames, the internal rules checking logic additionally generating an index value corresponding to the new intended destination address;
• and
• a queue configured to receive the forwarding descriptors and the index values corresponding to the new intended destination addresses of the data frames and to transmit each of the forwarding descriptors and the index values to the transmitter, the index value being used by the transmitter to obtain the new intended destination address for the data frames by querying the internal rules checking logic with the index value.

A multiport network device comprising:

• a receiver configured to receive data frames from a network, each of the data frames having header information that includes at least a source field indicating a source of the data frame and a destination field indicating an intended destination for the data frame;
• a transmitter configured to transmit the data frames to the network through a plurality of transmit ports;
• a memory coupled to the transmitter and the receiver, the memory storing the data frames received by the receiver and sending the data frames to the transmitter;
• internal rules checking logic coupled to an output of the receiver, the internal rules checking logic receiving the header information relating to the data frames received by the receiver and, based on the header information, generating a forwarding descriptor that identifies the transmit ports and a new destination address for the data frames, the internal rules checking logic overwriting the destination address of the data frames stored in the memory with the generated new destination address;
• and
• a queue configured to receive the forwarding descriptors and to transmit each of the forwarding descriptors to the transmitter, the transmitter retrieving the data frames from memory based on the forwarding descriptors.

A method of processing data frames in a network device comprising:

• receiving a data frame at one of a plurality of receive ports in the network device, the data frame having a header that includes at least a source field indicating a source of the data frame and a destination field indicating an intended destination for the data frame;
• determining a forwarding descriptor for the data frame based on the header information, the forwarding descriptor identifying transmit ports to output the data frame and a new destination address for the data frame;
• storing the forwarding descriptor and the new destination address as a pair of sequential words in a memory;
• forwarding the stored pair of sequential words to the transmit ports of the network device;
• transmitting the data frame from the transmit ports identified by the forwarding descriptor;
• and
• writing the new destination address in the destination field of the data frame before transmitting the data frame.