An ID/locator separation architecture is one of the most recognized technologies for Future Internet. In ID/locator separation architectures, an ID/locator mapping system is indispensable to provide location management in mobile environments. This paper conducts a comparative study on two approaches, centralized and distributed, for building ID/locator mapping systems. We develop analytical models on the signaling cost incurred in location update and location query procedures in centralized and distributed ID/locator mapping systems. We conduct extensive numerical analysis over mesh and tree topologies. Numerical results demonstrate that the distributed ID/locator mapping system with distributed hash table (DHT) has comparable signaling cost to the centralized ID/locator mapping system while providing higher scalability and robustness.