Network Virtualization implies the need for sharing network resources. However, exclusive resource allocation to users drives blocking probabilities and cost while potentially leaving precious resources under-utilized in constrained environments. Motivated by these observations, this paper analyzes careful overbooking according to Service Level Agreements that specify desired degrees of availability. Besides of full availability of the requested resources, a second level of limited availability, implying a well-defined reduction of the allocated resource, is taken into account. Particular attention is paid to the gain borderline, representing the possibility of accommodating one extra user beyond exclusive allocation without violating the SLAs. Simple but telling formulae provide insights into requirements for careful overbooking, worst-case capacity reduction factors from full to limited availability, and the conditions under which it is sensible to integrate users with different activity levels.

Nätverksvirtualisering bygger på resursdelning. Att dela resurser mellan för många användare (dvs för hög överbeläggning) leder till prestandaförluster, medan uteslutandet av potentiella användare är problematiskt med. Pappret undersöker rymliga gränser för överbeläggning med tanke på full eller en väldefinerad del av kapaciteten som användaren behöver.