System and method for reduced frame flooding

A network device, comprising:

• a plurality of line cards, each line card including a respective port, two of the ports being configurable as an aggregated port forming a single logical connection to another device;
• the port of a first one of the line cards being a first port operative to:
• (i) maintain an unknown address and a count, the unknown address being a network address for which there is no information at the first port identifying another port of the network device to which unicast frames containing the unknown address are to be forwarded, the count identifying the number of times frames containing the unknown address have been flooded from the first port to other ports of the network device;
• (ii) upon receiving unicast frames containing the unknown address from the other device while the count is less than a predetermined threshold, increment the count and flood the received frames to the ports of the other line cards;
• (iii) when the count has reached the predetermined threshold, determine whether there is information at the port of a second one of the line cards identifying a specific one of the ports of the network device to which unicast frames containing the unknown address are to be forwarded, and if so then obtain the information from the port of the second line card, whereupon the unknown address becomes known at the first port;
• and
• (iv) upon receiving unicast frames containing the now known address from the other device, forward the received frames to only the specific port identified in the information transferred from the port of the second line card to the first port;
• and
• the port of the second line card being a second port operative to:
• (i) receive unicast frames from ports of the other line cards and transmit the received frames to the other device;
• (ii) upon receiving unicast frames from ports of the other line cards, learn respective associations between addresses in the received frames and the ports from which the frames are received;
• and
• (iii) provide the information concerning the unknown address to the first port from the learned associations.

A network, comprising:

• a plurality of stations;
• a bridge coupled to a first subset of the stations;
• and
• a network device coupled to the bridge and to a second subset of the stations via corresponding physical ports of the network device, the coupling between the network element and bridge being in the form of an aggregated port including at least first and second physical ports, the network device being operative to:
• (i) maintain an unknown address and a count at the first port of the network device, the unknown address being a network address for which there is no information at the first port identifying another port of the network device to which unicast frames containing the unknown address are to be forwarded, the count identifying the number of times frames containing the unknown address have been flooded from the first port to other ports of the network device;
• (ii) upon receiving unicast frames containing the unknown address at the first port while the count is less than a predetermined threshold, increment the count and flood the received frames to the other ports of the network device;
• (iii) when the count has reached the predetermined threshold, determine whether there is information at the second port of the network device identifying a specific one of the ports of the network device to which unicast frames containing the unknown address are to be forwarded, and if so then transfer the information from the second port to the first port, whereupon the unknown address becomes known at the first port;
• and
• (iv) upon receiving unicast frames containing the now known address at the first port, forward the received frames to only the specific port identified in the information transferred from such other port to the first port.