Can we bridge the gap between average and peak loads in science networks?

Rajkumar  Kettimuthu
TrackLightning Talks Europaea Room
DescriptionBackbone networks are typically overprovisioned in order to sustain peak loads; thus, they are underutilized most of the time. For example, Internet2 has a policy of operating their network at light loads (25–30%) to allow the network to absorb surges in traffic. Internet2 upgrades the backbone interconnects when the weekly 95th-percentile metric is reliably above 30% of link capacity. Our analyses of traffic on ESnet between DOE facilities also show that there is a huge gap between peak and average utilization. Under the current mode of free access to the network, the traffic at peak load may range from flows that need to be transferred in near-real time, for example, for computation and instrument monitoring and steering, to flows that are less time-critical, for example, archival and storage replication operations. Thus, peak load does not necessarily indicate the capacity that is absolutely required.
Access to every expensive facility (including supercomputers and science instruments such as light source) in the science domain is regulated through an allocation process. Since a high-speed wide-area network is an expensive resource, too, why don’t we regulate access to it through allocation? We investigate charge-models for high-speed science networks. A dynamic pricing scheme, which is based on demand, will create incentives for less time-critical flows to move to periods of low demand. Such an approach will reduce the cost of building networks as the networks can be built to sustain only the necessary peak load. It will also help improved overall utilization of the network. But it does introduce numerous network and transport layer challenges including path computation, retransmission, tracking usage per user, handling price changes for long running transfers and preventing individuals from exploiting the system. We will present our preliminary investigation in this area.

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