Performance isolation is a serious issue in multi-tenant data center because interference among tenants can cause immense service troubles. Therefore, the present data center provides performance isolation among tenants. However, it is limited to system resources, not network resources, nevertheless oversubscription that is caused by network interference entails troubles. Therefore, the authors place Virtual Machines (VMs) with matching algorithm into servers based on the measured traffic distribution of VMs. They present their approach named Incubating that reduces oversubscription, also increases link utilization. They also show that their paper has better practicality compared with prior work because they consider traffic distribution as a time unit.