Patent ID: 7724734

Claim:
A method for controlling updating of a layer 3 host table in a packet forwarding device based on packet forwarding lookup miss counts, the method comprising: (a) routing layer 3 packets received at a packet forwarding device using a layer 3 host table containing entries corresponding to remote hosts; (b) for each layer 3 destination address for which a lookup in the layer 3 host table fails because the layer 3 host table lacks an entry for the layer 3 destination address: counting by the packet forwarding device a number of packets received for the destination address within a time period; maintaining a packet miss count table with entries for the layer 3 destination addresses for which the misses occurred and that are not in the host table, where the entries in the miss count table include the corresponding miss counts; determining whether an entry is present for the layer 3 destination address in the packet miss count table; in response to determining that an entry for the layer 3 destination address is not present in the packet miss count table, adding an entry for layer 3 destination address to the packet miss count table; in response to determining that an entry is present for the layer 3 destination address in the packet miss count table, incrementing a packet miss counter for the entry; and (c) replacing remote destination entries in the host table based on the miss counts by the packet forwarding device determining which of the entries in the miss count table should be used to replace entries in the host table based on the miss counts.