Internet Structure ELI MEIROM ARIEL ORDA SHIE MANNOR Introduction - - PowerPoint PPT Presentation
Internet Structure ELI MEIROM ARIEL ORDA SHIE MANNOR Introduction - - PowerPoint PPT Presentation
Network Formation Games with Heterogeneous Players and the Internet Structure ELI MEIROM ARIEL ORDA SHIE MANNOR Introduction inter-AS topology Inter-AS topology Overview Network formation games AS Autonomous System Model
Introduction – inter-AS topology
- AS – Autonomous System
- The Internet – A collection of interconnected ASs (40,000-50,000)
- An important example of a large, dynamic, complex network
- Known statistical properties: Node degree distribution, diameter,
clustering coefficient etc.
- Reconstructed by BGP updates
Inter-AS topology Overview Network formation games Model Statics Dynamics Data Analysis
Modeling the inter-AS topology
- Most models are stochastic
- ASs are “rational”, utilitarian enterprises – Game theory / Economic
approach.
- Previous works:
- Homogenous players
- Common solution concept – Nash Eq.
- Static properties (Price of Anarchy, Price of Stability)
- No comparison with the real AS-topology
- Finding Nash-equilibria is NP-Hard
Inter-AS topology Overview Network formation games Model Statics Dynamics Data Analysis
Overview
- Network Formation Games:
- A game theoretic approach for modeling the inter AS-topology
- The cost is composed from maintaining links and distances to other players
- Heterogeneous players
- Static properties:
- quality of stable solutions
- topological constraints
- Dynamic analysis:
- Time evolution of topological quantities
- Convergence rate
- Resulting equilibria, basin of attraction
- Data Analysis
Inter-AS topology Overview Network formation games Model Statics Dynamics Data Analysis
Model
- A network formation game
- Each AS is a player
- Heterogeneous players – Major players and minor players.
- Cost:
( ) ( ) ( , ) ( , ) ( ) ( ) ( , ) ( , )
A B A B
A A j T j T B B j T j T
C i deg i c A d i j d i j C i deg i c A d i j d i j
Number of edges Distance between AS i and AS j Relative importance
Inter-AS topology Overview Network formation games Model Statics Dynamics Data Analysis
Model (cont.)
- Solution concept: pairwise equilibrium (pairwise – interactions)
- Allow monetary transfers.
- Focus on:
- Dynamics
- Generated topologies
- Comparison with data.
,
( ) ( ) ( , ) ( , )
A B
A A j T j T ij ji j ij E
C i deg i c A d i j d i j P P
Inter-AS topology Overview Network formation games Model Statics Dynamics Data Analysis
Statics
- The major players form a clique (tier 1)
- Price of Stability = 1 (or asymptotically 1)
Inter-AS topology Overview Network formation games Model Statics Dynamics Data Analysis
Statics (Cont.)
- Monetary transfers: An edge will be established iff
- Non-empty core
- Distance to the clique
- Without monetary transfers:
Bounded by
- With monetary transfers:
Bounded by
( , ) ( , ) C i E ij C j E ij
2
(2 1) 4 2 1 A c A
2
| | 4 | | | |
A A A
A T cA T A T
Inter-AS topology Overview Network formation games Model Statics Dynamics Data Analysis
Dynamics - Settings
- Pairwise interactions
- Turns, acts
- Random vs. orderly
- Strategic Planning
- Timescales between cost evaluation and dynamics
- Preference order (under monetary transfers)
- “Free market”
- Strategic pricing
Inter-AS topology Overview Network formation games Model Statics Dynamics Data Analysis
Dynamics - Results
- Convergence is restricted to a limited subset of equilibria
- Fast Convergence – O(n)
- Emergence of a new “major player”
- By topological centrality, rather than type
Inter-AS topology Overview Network formation games Model Statics Dynamics Data Analysis
Dynamics – Results (cont.)
- Often, convergence is to the optimal state or to an asymptotically
- ptimal state.
- Monetary transfers does not always improve the social cost.
Inter-AS topology Overview Network formation games Model Statics Dynamics Data Analysis
Data Analysis
Inter-AS topology Overview Network formation games Model Statics Dynamics Data Analysis
Data Analysis (cont.)
Inter-AS topology Overview Network formation games Model Statics Dynamics Data Analysis
Data Analysis (cont.)
Inter-AS topology Overview Network formation games Model Statics Dynamics Data Analysis Reliability Model Statics Peering vs. transit Detecting Epidemics Diffusive processes Previous work Rare events Local ball algorithm Simulations References
Conclusions
- Established a heterogeneous AS network formation game
- Monetary transfers, different dynamical settings
- Statics
- Core-shell partition
- maximal distance, price of anarchy, price of stability
- Dynamics
- Fast convergence to a limited subset of equilibiria
- Explicit topologies
- Predictions confirmed by data
Inter-AS topology Overview Network formation games Model Statics Dynamics Data Analysis