Patent ID: 8059288
Filing Date: 2011-11-15
Classification: H04L

Abstract:
1. A communication apparatus comprising: a storage unit configured to store a value of a fixed address and a value of a variable address of a specific communication partner; a first detection unit configured to detect the specific communication partner by performing a first detection operation that transmits a broadcast or multicast packet and determines that the specific communication partner is detected if a response to the packet is received within a predetermined period of time and the response contains the value of the fixed address of the specific communication partner stored in the storage unit; and a second detection unit configured to detect the specific communication partner by performing a second detection operation that first transmits a unicast packet to the variable address of the specific communication partner, the value of which is stored in the storage unit, and determines that the specific communication partner is detected if a response to the unicast packet is received within a predetermined period of time and the response contains the value of the fixed address of the specific communication partner stored in the storage unit, and repeats the transmission of the unicast packet to the variable address of the specific communication partner, the value of which is different from the value of the variable address in the first transmission of the unicast packet, if no response containing the value of the fixed address of the specific communication partner stored in the storage unit is received within the predetermined period of time, wherein if the specific communication partner is not detected by said first detection unit, then the detection of the specific communication partner is performed by said second detection unit, or if the specific communication partner is not detected by said second detection unit, then the detection of the specific communication partner is performed by said first detection unit.