Patent ID: 8467403

Claim:
A method, comprising: updating, by a packet switching device using multistage forwarding lookup operations, an egress forwarding information base (egress FIB) on each of a plurality of line cards of the packet switching device to additionally include forwarding information for a stream of packets exiting a second interface of one of the plurality of line cards in addition to forwarding information currently used for forwarding packets of the stream of packets from a first interface of the plurality of line cards; and in response to identifying that said egress FIB has been said updated on each of the plurality of line cards: updating an ingress forwarding information base (ingress FIB) on at least one line card of the packet switching device to reflect the stream of packets exiting the second interface instead of the stream of packets exiting the first interface; wherein said operation of identifying that said egress FIB has been said updated on each of the plurality of line cards includes waiting until each of the plurality of line cards has acknowledged that their respective egress FIB has been said updated.