A duplicate detection method is disclosed for reducing redundant traffic in an ad hoc network. The duplicate detection method of the present invention includes receiving a first packet having a content identifier and a subcontent identifier, storing the content identifier and the subcontent identifier of the first packet, receiving a second packet, extracting a content identifier from the second packet, determining whether the content identifiers of the first and second packets are identical, extracting, when the content identifiers are identical, a subcontent identifier from the second packet, determining whether the subcontent identifiers of the first and second packets are identical, determining, when the subcontent identifiers of the first and second packets are identical, the second packet is a duplicate of the first packet.