How does MSCS do IP failover?
MSCS has the ability to failover (move) an IP address from one cluster node to another. The ability to failover an IP address depends on two things: 1) support for dynamic registration and deregistration of IP addresses, and 2) the ability to update the physical network address translation caches of other systems attached to the subnet on which an address is registered. Dynamic address (de)registration is already implemented in Windows NT Server to support leasing IP addresses using the Dynamic Host Configuration Protocol (DHCP). To bring an IP Address resource online, the MSCS software issues a command to the TCP/IP driver to register the specified address. A similar command exists to deregister an address when the corresponding MSCS resource is taken offline. The procedure for updating the address translation caches of other systems on a LAN is contained in the Address Resolution Protocol (ARP) procedure, which is implemented by Windows NT Server. ARP is an IETF standard, RFC 826. RF
