Internet overlay services must adapt to the substrate network topology and link properties to achieve high performance. A common overlay structure management layer is desirable for enhancing the architectural modularity of service design and deployment. For instance, new link probing techniques can be incorporated into the common structure layer such that a large number of overlay services can benefit transparently. Additionally, a shared substrate-aware overlay structure can potentially reduce redundant per-service link-selection probing when overlay nodes participate in multiple services. The concept of building services on a common structure management layer fits well with unstructured services, those that do not place specific requirements on the overlay connectivity structure (e.g., Gnutella). Despite the benefits, it is unclear how the distributed hashtable (DHT) service can take advantage of a serviceindependent structure management layer, considering recently proposed scal...