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Hitesh Ballani, Paul Francis, Tuan Cao and Jia Wang Cornell University and AT&T Labs-Research Presented by Gregory Peaker, Zhen Qin. Making Routers Last Longer with ViAggre. Outline. Motivation ViAggre design Allocating aggregation points Evaluation Deployment Discussion. Motivation.
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Hitesh Ballani, Paul Francis, Tuan Cao and Jia Wang Cornell University and AT&T Labs-Research Presented by Gregory Peaker, Zhen Qin Making Routers Last Longer with ViAggre
Outline • Motivation • ViAggre design • Allocating aggregation points • Evaluation • Deployment • Discussion
Motivation • Large Routing Table More FIB space on Routers • Rapid future growth IPv4 exhaustion IPv6 deployment
Does FIB Size Matter? • Technical concerns Power and Heat dissipation problems • Business concerns Large routing table Less cost-effective networks Price per bit forwarded increases Cost of router memory upgrades ISPs are willing to undergo some pain to extend the life of their routers
Allocating aggregation points • A router’s FIB size (Fr): • routes to the real prefixes in the virtual prefixes it is aggregating • routes to all the virtual prefixes • routes to the popular prefixes • LSP mappings for external routers
Allocating aggregation points • Traffic stretch: • packets from router i to prefix p belonging to a virtual prefix v are routed through router k • j is the egress-router for a traffic from router k to prefix p • i chooses k as an aggregation point that is closest in terms of IGP metrics, where k is also belonging to virtual prefix v
Allocating aggregation points • Definition of can_server • If router i were to aggregate virtual prefix v, which routers can it serve without violating the stretch constraint C. • In accordance with can_server relation while trying to minimize the worst FIB size, an algorithm was proposed to designate all routers are served for a virtual prefix
Evaluation • Impact on Traffic • Traffic stretched using different router level path than native path • Increase Router Load
Evaluation using ISPs • Tier 1 • Extend life of routers from 2007 to 2018 • 39% increase load on routers • 1.5% of prefixes for 75.5% traffic • 5% of prefixes for 90.2% traffic
Evaluation using ISPs • Tier 2 • Apply routing table for their customers • Use default table for all other customers • Negligible traffic stretch (<0.2 msec) • Negligible Increase in Load (<1.5%)
Deployment • Can be incrementally deployed • Can be deployed on small scale • Incentive for deployment • No Change to ISP’s routing table • Does not affect routers advertised to neighbors • Does not restrict routing policies • Extra configuration • Could be automated • Vendor support + cheaper routers
Conclusion & Offense • Can be used by ISPs today • 10x reduction in FIB size • Negligible traffic stretch • Negligible load increase • ISPs extend lifetime of routers • A simple and effective first step