att_abstract={{The benefit of Class-of-Service (CoS) is an important
topic in the “Network Neutrality” debate. Some proponents of
network neutrality suggest that over-provisioning is a viable
alternative to CoS, and that there is no need for differentiated
services in an IP backbone for users needing better-than-besteffort
service. In this paper, we quantify the extra capacity
requirement for an over-provisioned classless (i.e., best-effort)
network compared to a CoS network providing the same delay
or loss performance for premium traffic. We first develop a link
model that quantifies the Required Extra Capacity (REC). To illustrate
key parameters involved in analytically quantifying REC,
we start with simple traffic distributions. Then, for more bursty
and realistic traffic distributions (e.g., long-range dependent), we
find the REC using ns-2 simulations of CoS and classless links.
We, then, use these link models to quantify the REC for realistic
network topologies under various scenarios including situations
with “closed loop” traffic generated by many TCP sources that
adapt to the available capacity. We also study the REC under
link and node failures. We show that REC can be significant even
when the proportion of premium traffic requiring performance
assurances is small, a situation often considered benign for the
over-provisioning alternative. We also show that the impact of
CoS on best-effort traffic is relatively small while still providing
the desired performance for premium traffic.}},
	att_authors={kr2812, jh2974, 7917427},
	att_tags={Neutrality, Differentiated Service, Class-of-Service, IP Backbone, provisioning, SLAs},
	author={Kadangode Ramakrishnan and Joseph Houle and Rita Sadhvani and Murat Yuksel and Shivkumar Kalyanaraman},
	institution={{Computer Networks}},
	title={{Required Extra Capacity: Required Extra Capacity: A Comparative Estimation of Overprovisioning Needed for a Classless IP Backbone}},