Cristian Lumezanu Dave Levin Neil Spring PeerWise Discovery and Negotiation of Faster Paths

Routing Overlays PeerWise Discovery and Negotiation of Faster Paths HotNets 2007 Deployment COST is LOW Potential BENEFIT is HIGH

Scalability? PeerWise Discovery and Negotiation of Faster Paths HotNets 2007 Probing should be done more selectively A B C

Routing overlays should include an incentive mechanism Fairness? PeerWise Discovery and Negotiation of Faster Paths HotNets 2007 cost benefit > 1 cost benefit < 1

PeerWise PeerWise Discovery and Negotiation of Faster Paths HotNets 2007 PeerWise Nodes that can help each other find better paths peer Nodes negotiate and establish pairwise connections to each other Motivation Cost-benefit ratio known before committing any resources Models autonomous system peerings in the Internet Overlays built on self-interest rather than altruism

PeerWise PeerWise Discovery and Negotiation of Faster Paths HotNets ms A B C D 50ms 30ms 40ms

PeerWise properties PeerWise Discovery and Negotiation of Faster Paths HotNets 2007

PeerWise properties PeerWise Discovery and Negotiation of Faster Paths HotNets 2007

Is mutual advantage common? PeerWise Discovery and Negotiation of Faster Paths HotNets 2007 A B C E G D F Difference between the number of routes each node uses the other for after all peerings have been established PEERING SCORE PeerWise prototype with global knowledge 256 DNS server data set gathered using the King method Each node sends data to all other nodes PeerWise prototype with global knowledge 256 DNS server data set gathered using the King method Each node sends data to all other nodes EXPERIMENT SETUP

Is mutual advantage common? PeerWise Discovery and Negotiation of Faster Paths HotNets % of the pairs of nodes are happy with existing peerings % of pairs peering score 

PeerWise properties PeerWise Discovery and Negotiation of Faster Paths HotNets 2007

Finding shorter detours PeerWise Discovery and Negotiation of Faster Paths HotNets ms 100ms Triangle inequality violations indicate the existence of shorter one-hop detours A B C At least 66% of the pairs of nodes in our datasets are long sides in TIVs We use network coordinates to find triangle inequality violations flaws in

Network coordinates and TIVs PeerWise Discovery and Negotiation of Faster Paths HotNets ms 39ms 62ms A B C 38ms 42ms 26ms B A C InternetMetric space TIVs allowed AC > AB + BC No TIVs AC < AB + BC error(AC) = -36ms Long sides shrink Sum of short sides grows

Embedding errors and TIVs PeerWise Discovery and Negotiation of Faster Paths HotNets 2007 The more negative the embedding error of an edge, the higher the probability that the edge is a long side in a TIV The more positive the embedding error of an edge, the higher the probability that the edge is a short side in a TIV …and thus has a one-hop shorter detour …and thus is part of a one-hop shorter detour If long sides shrink If sum of short sides grows

PeerWise properties PeerWise Discovery and Negotiation of Faster Paths HotNets 2007

Performance PeerWise Discovery and Negotiation of Faster Paths HotNets 2007 % of pairs direct pathbest one-hop path Latency (ms) 100 PeerWise path PeerWise reduces latency by an average of 20%

Conclusions PeerWise Discovery and Negotiation of Faster Paths HotNets 2007

Future Work PeerWise Discovery and Negotiation of Faster Paths HotNets 2007 Why is there mutual advantage? Extensions for low-loss and failure-free paths Future Work Deployment

Are one-hop detours enough? PeerWise Discovery and Negotiation of Faster Paths HotNets 2007 Latency (ms) % of pairs direct path best one-hop detour path 25% of direct paths are longer than 100ms 3% of detour paths are longer than 100ms 50% improvement in average latency

Connectivity PeerWise Discovery and Negotiation of Faster Paths HotNets 2007 % of nodes detour score Percentage of destinations that a node can reach using its peerings, out of all reachable destinations global knowledge limited knowledge (32 neighbors) 78% of nodes can reach more than 60% of their destinations, with global knowledge 60% of nodes can reach more than 60% of their destinations, with limited knowledge

Embedding errors and TIVs PeerWise Discovery and Negotiation of Faster Paths HotNets 2007 The more negative the embedding error of an edge, the higher the probability that the edge is a long side in a TIV The more positive the embedding error of an edge, the higher the probability that the edge is a short side in a TIV …and thus has a one-hop shorter detour …and thus is part of a one-hop shorter detour Percentage of how many times a pair of nodes forms a long side in a TIV out of total number of presences in TIVs TIV SCORE

Embedding errors and TIVs PeerWise Discovery and Negotiation of Faster Paths HotNets embedding error TIV score As the estimation error becomes more negative the nodes form more and more long sides estimated distance – real distance more long sides more short sides