Nxt-Freedom: Considering VDC-based Fairness in Enforcing Bandwidth Guarantees in Cloud Datacenter

In cloud datacenter, it should be rational to enforce fair allocation on network resources among VDCs (virtual datacenters) in terms of multi-tenant model. Traditionally, cloud networks are shared in a best-effort manner, making it hard to reason about how network resources are allocated. Prior works concentrate on either providing minimum bandwidth guarantee or achieving work-conserving based on the VM-to-VM flow policy or per-source policy, or both. However, fair allocation on redundant bandwidth among VDCs is ignored. In this paper, we design NXT-Freedom, a bandwidth guarantees enforcement framework that divides network capacity based on per-VDC fairness while achieving work-conservation. To ensure per-VDC fair allocation, a hierarchical max-min fairness algorithm is proposed. To be applicable to non-congestion-free network core and to be scalable, NXT-Freedom decouples computing per-VDC allocation from enforcing the allocation. Through evaluation of a prototype, we show that NXT-Freedom achieves per-VDC performance isolation, and can be rapidly adapted to flow variation in cloud datacenter.