NETWORK ADDRESS TRANSLATION WITH GATEWAY LOAD DISTRIBUTION

摘要

Gateway and NAT services to a single host or large number of hosts on a local network using a redundancy group having gateway devices. A pool of unique IP addresses (310) are partitioned into address blocks (310a-310d), one of which is assigned to a gateway device (212, 214, 216, 218). Using the unique IP addresses in its assigned address block, the gateway device translates local IP addresses of hosts on a local network to unique IP addresses from the gateway device's assigned address block for host packets destined for outside networks and creates a mapping of the translation. The gateway device notifies other gateway devices in the redundancy group of the mapping. A master mapping database or a local mapping database is updated whenever one of the gateway devices performs a translation. In the event that one of the gateway devices ceases forwarding of outgoing packets for a host using the gateway device's virtual MAC address (VMAC), that virtual MAC address is re-assigned to an operating gateway device in the redundancy group (212, 214, 216, 218) to permit continued forwarding of the host's packets destined for outside networks.