Optimal virtual network migration: A step closer for seamless resource mobility

Network Virtualization provides operators with the ability to move components of a virtual network (VN), or even the entire VN, between physical hosts, in real-time and seamlessly to the end-users.This paper addresses virtual resource mobility from a fault management perspective: (i) it proposes VN Clone migration, which requires no assumptions regarding the protocols running inside the virtual networks or its own architecture; (ii) and it proposes virtual network re-embedding-node-link formulation (VNRE-NLF), an integer linear programming formulation to solve the online virtual network re-embedding problem as a simultaneous optimization of virtual nodes and virtual links, providing the optimal bound for the migration of virtual networks from physical resources prone to failure. This approach aims at minimizing the overall VN migration cost per re-embedding: (i) the number of virtual nodes migrated; and (ii) the physical bandwidth consumption.The results are very promising: the VN Clone migration achieves no VN downtimes and it takes just a few seconds to be fully performed. This makes the VN Clone approach suitable both for non- and real-time traffic. The obtained results of VNRE-NLF show that VNs are highly resilient (i.e. resilience factor higher than 0.8) to fault events if no more than 2% of the physical resources are prone to failure. Moreover, it shows that it is not only important to have enough spare capacity to re-accommodate the virtual nodes and virtual links directly affected by the fault, but also to have additional capacity to accommodate virtual link re-assignments and virtual node migrations.