A method and apparatus for reducing the number of write operations during
route updates in router forwarding engines eliminates "excess" (i.e.,
"redundant") writes to the routing trie. One or more writes are
"redundant" with respect to another write if the timestamp of the other
write is the same as or later than (by an amount less than a given
threshold) the timestamp of each of the one or more writes, and if the
state of the routing trie after the other write has been applied is
equivalent whether or not any of the one or more writes have also been
applied. Excess writes may be advantageously eliminated when routes are
either added to or withdrawn from the routing trie, and deleted subtrees
may be advantageously cached for subsequent re-addition thereto.