A method for hitless restart of layer 3 packet forwarding includes
replicating some but not all state information from a master management
service module to a slave management service module. The master
management service module builds a layer 3 routing table by participating
in layer 3 routing protocols. The layer 3 routing table is stored in
memory. The master management service module builds a first layer 3
forwarding table and stores the forwarding information in hardware. A
slave management service module receives a copy of the first layer 3
forwarding table from the master management service module. When the
master management service module fails, the slave management service
module initiates construction of a routing table by participating in
layer 3 routing protocols. Packet forwarding is not interrupted because
forwarding using hardware entries continues. The slave management service
module links entries in the newly constructed routing table to those
stored in the forwarding table.