Rade Stanojevic Using Tuángòu to Reduce IP Transit Costs Rade Stanojevic (Joint work with Ignacio...
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Transcript of Rade Stanojevic Using Tuángòu to Reduce IP Transit Costs Rade Stanojevic (Joint work with Ignacio...
Rade Stanojevic
Using Tuángòu to Reduce IP Transit Costs
Rade Stanojevic(Joint work with Ignacio Castro and Sergey Gorinsky)
ACM CoNext 2011
Tokyo, Japan
团购 (tuángòu) = group-buying
Rade Stanojevic
Part 1: Tuángòu for IP transit
ACM CoNEXT 2011 CIPT: Using Tuángòu to Reduce IP Transit Costs 2
Rade Stanojevic
IP transit as a service
ACM CoNEXT 2011 CIPT: Using Tuángòu to Reduce IP Transit Costs 3
IP transit• Lower tier ISPs customers of
higher tier ISPs• Critical for global connectivity• Fee depends on traffic
Rade Stanojevic
IP Transit costs
ACM CoNEXT 2011 CIPT: Using Tuángòu to Reduce IP Transit Costs 4
Affects almost every online entity IP transit cost-reduction technologies
ISP peeringCDNMulticastP2P localizationTraffic shaping (P2P throttling)
The less traffic on transit links the lower the cost
Rade Stanojevic
Simple idea:
Exploit the IP transit market properties:Price elasticity 95th-percentile pricing
CIPT: Cooperative IP transit
ACM CoNEXT 2011 CIPT: Using Tuángòu to Reduce IP Transit Costs 5
purchase in group and share the costs
Rade Stanojevic
IP transit billing: two key properties
ACM CoNEXT 2011 CIPT: Using Tuángòu to Reduce IP Transit Costs 6
• Price elasticity
• Peak based traffic metering: 95th-percentile pricing
Submodularity of the peak: peak(f) + peak(g) ≥ peak(f+g)
Voxel pricingSource= https://www.voxel.net/ip-services(as accessed on June 2011)
Rade Stanojevic
CIPT as a cooperative game
ACM CoNEXT 2011 CIPT: Using Tuángòu to Reduce IP Transit Costs 7
• How to share the benefits of cooperation?• Shapley value
• ‘Fair’, exists and unique for any cooperative game• Individually rational (everyone better off in the coalition)• Hard to calculate exactly for large number of players• Monte-Carlo method for accurate estimation
Rade Stanojevic
Part 2: Quantifying CIPT benefits
ACM CoNEXT 2011 CIPT: Using Tuángòu to Reduce IP Transit Costs 8
Rade Stanojevic
From peering to transit traffic
ACM CoNEXT 2011 CIPT: Using Tuángòu to Reduce IP Transit Costs 9
• ISP Transit traffic data: not available• ISP Peering traffic data: available at some IXPs • Peering traffic as a proxy for estimating transit traffic
Ttransit(t) = cTpeering(t)
• Validation using 4 medium-sized (academic) ISPs
Rade Stanojevic
Obtaining peering traffic data
ACM CoNEXT 2011 CIPT: Using Tuángòu to Reduce IP Transit Costs 10
2. Transform images into numeric data on peering traffic
1. Peering traffic data of 264 ISPs from 6 IXPs
Optical function/character recognition
Collection of mrtg images
Rade Stanojevic
Expected cost savings in the range of 8%-56%ISP traffic volume distribution, peak-hour profile, nmb of transit providers, etc.
Per ISP savings from $1K to few $100K per yearSmallest ISPs save >90%, Largest ISPs save <10%
BreakdownAround 1/3 of the savings come from the 95th-pctThe rest comes from the elastic pricing
Check the paper for details…
Country-wide coalitions
ACM CoNEXT 2011 CIPT: Using Tuángòu to Reduce IP Transit Costs 11
Rade Stanojevic
Small (random) coalitions provide most of total attainable gains
CIPT coalition size: low of diminishing returns
ACM CoNEXT 2011 CIPT: Using Tuángòu to Reduce IP Transit Costs 12
Rade Stanojevic
Beyond gains sharing
ACM CoNEXT 2011 CIPT: Using Tuángòu to Reduce IP Transit Costs 13
Organizational embodimentPhysical infrastructurePerformance/SLAsTraffic confidentialityTransit providers and strategic issues
Rade Stanojevic
Open problems
CIPT coalition formation process? Shapley value too implicit. Simpler metrics?Tuángòu in other (price-elastic) domains?
IP transportWired/wireless accessMobile voice/txt/data
ACM CoNEXT 2011 14CIPT: Using Tuángòu to Reduce IP Transit Costs
Rade Stanojevic
Team-buying has potential for cutting IP transit billShapley value as a mechanism for cost sharingUnique dataset of traffic data from 264 ISPs with heterogeneous sizes and temporal properties
Conclusions
ACM CoNEXT 2011 CIPT: Using Tuángòu to Reduce IP Transit Costs 15
Rade Stanojevic
Backup slides
ACM CoNEXT 2011 CIPT: Using Tuángòu to Reduce IP Transit Costs 16
Rade Stanojevic
Cooperative IP Transit (CIPT)
ACM CoNEXT 2011 CIPT: Using Tuángòu to Reduce IP Transit Costs 17
Tuángòu = team-buyingcoalitional arrangement for bulk buying of IP transit
CIPT gains
Per-Mbps price reduction thanks to elastic pricing and peak-based (95th-pct) metering
Rade Stanojevic
Price decay vs. traffic growth
ACM CoNEXT 2011 CIPT: Using Tuángòu to Reduce IP Transit Costs 18
Source= https://www.telegeography
Per-Mbps transit price decline vs. interdomain traffic growth
Rade Stanojevic
Shapley value definition
ACM CoNEXT 2011 CIPT: Using Tuángòu to Reduce IP Transit Costs 19
Shapley value(i) ISP i's expected marginal contribution if the players join the coalition one at a time, in a uniformly random order
N = number of playersc(S)= cost of coalition SS(π, i) = set of players arrived in the system not later than iπ = permutations of the set of players N
i’s marginal contribution
Rade Stanojevic
• Monte Carlo method*• We estimate the Shapley value as the average cost contribution
over set πk of K randomly sampled arrival orders.
• Estimation accuracy• K is the knob controlling the accuracy
• We use K = 1000 to keep the error under 1%
(*) D. Liben-Nowell, A. Sharp, T. Wexler, K. Woods, “Computing Shapley Value in Cooperative Supermodular Games”, Preprint, 2010. R. Stanojevic, N. Laoutaris, P. Rodriguez, “On Economic Heavy Hitters: Shapley Value Analysis of the 95th-Percentile Pricing”, Proc. of ACM IMC 2010.
Shapley value estimation
ACM CoNEXT 2011 CIPT: Using Tuángòu to Reduce IP Transit Costs 20
Rade Stanojevic
Peering = 35-40% of the total traffic.
Peering and transit follow very similar patterns.
Peering-transit traffic similarity
ACM CoNEXT 2011 CIPT: Using Tuángòu to Reduce IP Transit Costs 21
Rade Stanojevic
Absolute aggregate CIPT gains grow with IXP size (in terms of billed traffic)
Relative aggregate CIPT gains decrease with IXP size
Aggregate CIPT gains
ACM CoNEXT 2011 CIPT: Using Tuángòu to Reduce IP Transit Costs 22
Rade Stanojevic
Per-partner CIPT gains
ACM CoNEXT 2011 CIPT: Using Tuángòu to Reduce IP Transit Costs 23
Absolute individual CIPT gains grow with ISP size
Relative individual CIPT gains decrease with ISP size
There are large gains for all CIPT members