The packing problem of uncertain multicasts

Abstract

Multicast performs better than unicast in delivering the same content from a fixed single source to a set of destinations. Many efforts have been made to optimize such kind of deterministic multicast, such as minimizing the transmission cost of each multicast session. In practice, it is not necessary that the source of each multicast session has to be in a specific location, as long as certain constraints are satisfied. Accordingly, applications usually meet a novel multicast with uncertain sources, ie, uncertain multicast. That is, multiple nodes have the responsibility to act as the root node of a multicast session. Prior proposals have addressed an uncertain multicast by constructing the minimum cost forest. However, it is still unknown how to efficiently share the network resources, when a set of uncertain multicast occupies the network simultaneously. To tackle such a challenging issue, we present the packing problem of uncertain multicasts (MPU) to minimize the total transmission cost, under the constraint of link capacity. We prove that the MPU problem is NP-hard. An intrinsic solution is constructing the minimum cost forest for each uncertain multicast individually. This method, however, is inefficient and may be infeasible because of the constraint of link capacity. Thus, we design 2 dedicated greedy methods, named priority-based and adjusting congested link, to approximate the optimal solution. The comprehensive results indicate that both of our 2 methods can find a feasible solution for the MPU problem. Moreover, given a set of uncertain multicasts, the adjusting congested link method can generate a desired transmission structure for each uncertain multicast and achieve the least total cost when packing them. KEYWORDS packing problem, routing algorithm, uncertain multicast 1 Concurrency Computat: Pract Exper. 2017;29:e3985.wileyonlinelibrary.com/journal/cpe

New advances in future network technologies

“…For example, the problem of uncertain multicast is usually caused by content replica design in content distribution network (CDN) and datacenter network (DCN). Ren et al try to address the packing problem of uncertain multicast to minimize the total transmission cost in their paper “The Packing Problem of Uncertain Multicasts.” To give effective solution of network resources sharing when a set of uncertain multicast occupy the network simultaneously, they formally present the packet problem of uncertain multicast. Then they prove this problem is NP‐hard and design two greedy algorithms approximating the optimal solution.…”

Minimum-cost forest for uncertain multicast with delay constraints

“…That is, destination nodes can be served by any server node in S . Such multicasts with flexible pseudo source nodes are defined as uncertain multicast [14][15][16] . Such a new multicast paradigm brings high expectation for more robust and flexible network services but incurs some essential technical challenges.…”