A Low-stretch Object Migration Scheme for Wide-area Environments

Abstract

We propose a low-stretch scheme for locating mobile objects in wide-area computing environments. Locating mobile objects in distributed computing systems is a non-trivial problem and has been investigated for decades. The forwarding address algorithm, perhaps the most popular algorithm, requires the previous holder of the object to point to the successive holder, and to forward all requests along this pointer. However, this approach cannot provide any access stretch bounds for wide-area settings, and can incur unlimited communication overhead. This is unacceptable when a large number of objects simultaneously move or when numerous referencers attempt to access an object that has moved. We propose an active update method where nodes in the vicinity of the object's location are notified of its new location via localized update messages. Moreover, we will utilize the overlay topology information to minimize these messages. Referencers beyond the scope of the update will still be able to safely access the object. We will demonstrate that these updates maintain access stretches low even in wide-area settings.