Research On Key Issues Of Power-Aware Core Router Design

Power consumption of Information and Communication Technology (ICT) is veryhuge, and varies more than5%of the worldwide power consumption. Moreover, thereis a trend of a notable increase of the ICT power consumption in the future. Core routersare key equipments of Internet, and consume a considerable amount of power.There are lots of works focus on Green Internet recently. We propose to moredeeply explore the power saving potential via the architectural redesign of core routers.Router with the new architecture is named as GreenRouter. Line-card in routers is sepa-rated into two parts: network interface and packet processing component. Packetprocessing components dominate power consumption in a router. While traffic volumeis not high, traffic from all network interfaces share all packet processing capacities,thus can be aggregated to a few active packet processing components on demand andother inactive packet processing components can be shut down to save power. The maincontributions are as follows:1. An architectural redesign of core router is proposed in order to implement shar-ing of packet processing capacities and then to achieve power saving. The network in-terfaces and packet processing components in line-cards are named as DB (DaughterBoard) and MB (Mother Board) in GreenRouter respectively. An extra switching fabricis used to implement sharing of MB’s processing capacities. And a distributed dis-patching system is designed to allocate traffic from DBs to MBs. The impacts of thenew architecture are also discussed.2. A flow slice based dispatching policy is proposed. Flow slice is used instead offlow in traffic dispatching. It is more flexible to dispatch traffic with flow slices thanwith flows. So more power saving is gained and QoS performance is better. Real tracedriven experiments and simulations are conducted. GreenRouter can adapt traffic fluc-tuation and can save significant power and QoS constrains are also satisfied with flowslice based policy. With a typical traffic load--30%in backbone links, GreenRoutercan save nearly18%of power compared to traditional routers.3. A packet based dispatching policy is also proposed. The new policy improvesthe power saving gain of GreenRouter while QoS constrains are satisfied at the same time. Reordering is taking place at the exit of network interfaces in order to meet therequirement of reordering ratio in QoS constrains. Real trace driven experiments showthat packet based dispatching can save about10%more power than flow slice baseddispatching.