Edge Provisioning and Fairness in VPNDiffServ Networks Customers of Virtual Private Networks (VPNs) over Differentiated Services (DiffServ) infrastructure are most likely to demand not only security but also guaranteed QualityofService (QoS) in pursuance of their desire to have leasedlinelike services. However, expectedly they will be unable or unwilling to predict the load between VPN endpoints. This paper proposes that customers specify their requirements as a range of quantitative services in the Service Level Agreements (SLAs). To support such services Internet Service Providers (ISPs) would need an automated provisioning system that can logically partition the capacity at the edges to various classes (or groups) of VPN connections and manage them efficiently to allow resource sharing among the groups in a dynamic and fair manner. While with edge provisioning a certain amount of resources based on SLAs (traffic contract at edge) are allocated to VPN connections, we also need to provision the interior nodes of a transit network to meet the assurances offered at the boundaries of the network. We, therefore, propose a twolayered model to provision such VPNDiffServ networks where the top layer is responsible for edge provisioning, and drives the lower layer in charge of interior resource provisioning with the help of a Bandwidth Broker (BB). Various algorithms with examples and analyses are presented to provision and allocate resources dynamically at the edges for VPN connections. We have developed a prototype BB performing the required provisioning and connection admission.

BwShare: Efficient Bandwidth Guarantee in Cloud with Transparent Share Adaptation Abstract   Bandwidth guarantee (BwG) is a highly desired feature in cloud data centers for enabling tenants (i.e., users) to achieve predictable performances. However, such a function currently is not commonly available in clouds since it potentially lowers the utilization efficiency of the network fabric (i.e., denoted network efficiency). The reasons lie in two aspects. First, tenants often present a timevarying andor spatiallyvarying bandwidth demands. Second, the current cloud network architecture makes it hard to enable tenants to reuse unused bandwidth guarantees efficiently. To tackle these challenges, we propose BwShare, a novel bandwidth guarantee scheme in cloud data centers that can effectively improve the network efficiency at both the guaranteed level and the besteffort level in a synergized manner, while current approaches only adopt one of them. Such a design goal is achieved through two components: an adaptive bandwidth guarantee adaptation module (i.e., BGAdaptor) and a transparent work conservation module (i.e., WCEnabler). BGAdaptor improves the network efficiency at the guaranteed level by adjusting bandwidth guarantees among VMs of the same tenant based on traffic monitoring. WCEnabler works at the besteffort level by enabling VMs to reuse idled bandwidth efficiently and freely without disrupting bandwidth guarantees. The two modules can also facilitate each otherxe2x80x99s performance. Extensive experiments show that BwShare can effectively improve the network efficiency while providing the function of bandwidth guarantee in cloud data centers.