u201c a u201d the segment through which a vrrp advertisement message passes is defined as a vlan 1 and the segment through which communication data among the host 1 the vm 1 and the vm 2 passes is defined as a vlan 2 at this stage no data is stored in either the management table storage unit 1005 in the virtual switch or the fdb 32 in the l2 switch fig1 illustrates an operation for generating an entry in the management table storage unit 1005 when the vrrp is set the master node regularly performs multicast transmission of vrrp advertisement messages the virtual switch of the server 1 which has received a vrrp advertisement message generates in the case where a reception port which has received the vrrp advertisement message is different from the last reception port an entry in the management table storage unit 1005 more specifically the virtual switch of the server 1 registers the identifier u201c p1 u201d of the reception port for the vrrp advertisement message as the connection if in the management table storage unit 1005 furthermore snooping on the vrrp advertisement message is performed and u201c a u201d and u201c 1 1 1 1 u201d are registered as the virtual mac address and the virtual ip address respectively into the management table storage unit 1005 in contrast the virtual switch of the server 2 registers the identifier u201c p4 u201d of the.