Giochi cooperativi per incentivare la
collaborazione tra operatori Internet
per l’offerta di nuovi servizi a valore
aggiunto
Stefano Seccia
in collaborazione con J.-L. Rougiera, A. Pattavinab, M. Mycekc , M. Pioroc , A.
Tomaszewskic
a Telecom ParisTech, France;
b Politecnico di Milano, Italy;
c Warsaw University of Technology, Poland
Corso di Teoria dei Giochi, Applicazioni
Collegio Borromeo, Università di Pavia, 29-30 Marzo 2010, Pavia
Rationales
the big picture
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COORDINATED Peering ROUTING
(recall)
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Current inter-domain routing
current practice across top-tier interconnections

Current BGP routing in the Internet core
• Routing decisions based on unilateral costs
• Lack of routing coordination, especially on peering links
• Routing on peering links is increasingly unstable
Change of colour = change of top-50 carrier border (10 min sampling)
- High risk of congestions  route deviations
- OBJECTIVE: control the coupling between IGP and BGP routing
ISP
international
ISP
international
ISP
national
ISP
regional
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ISP
national
ISP
regional
ISP
regional
ISP
national
ISP
regional
ISP
national
ISP
regional
ISP
regional
Coordinated inter-provider BGP routing
a game-theoretic approach

ClubMED: Coordinated Multi-Exit Discriminator game
• selfish game + dummy game + congestion game
- Is a potential game: Nash equilibrium minimum of the potential function
• IGP cost variations  potential min. threshold enlargement of the Nash set
• Coordination policies to select efficient multipath equilibrium sets
Tp
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5
Toward an extended peering framework
Community A
Ra
c1
I
R 1I
c1
c1,2
I
c2 I
R 2I
AS I
l1
l2
R1II
II
Rb
R2III
AS II
c2III
Rc
c2,3III
cIII,III
c3II
MEDA = c2I
R3II
l3
R3III
Composite MEDA = c1,3II , c1I
c3III
Community C
Community B
MEDA = c1I
MED=5
AS III
•Each peer sees the extended peering frontier as a unique frontier such
as for the classical peering
•Routing decision: where to route the egress aggregate flow from its community
toward the other communities of the other peers
•The receiving peer deaggregates the flow: one toward its destination, one transiting
toward another peer folllowing BGP
•Gd is now characterized by ingress costs and transit costs
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6
An extended peering game example
A
1
4
AS II
3
B 12
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4
2
3
AS I
2
l1
14
1
l2
3
3
1
AS III
7
l3
15
8
3
9
C
COOPERATIVE CONNECTION-ORIENTED ROUTING
Community A
Ra
c1 I
I
c1,2I
l1
AS I
R1
INFRES
R 2I
l2
R1II
c1II
Rb
c3II
MEDA = c2I
R2III
c2III
Rc
c2,3III
cIII,III
AS II
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c2 I
R3II
l3
R3III
Composite MEDA = c1,3II , c1I
c3III
AS III
Community C
Community B
MEDA = c1I
MED=5
Cooperative provider alliances
architecture and protocol extensions

Inter-provider MPLS/G-MPLS provisioning
• Definition of the functional architecture
• An end-to-end network service as result of service elements composition
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Cooperative provider alliances
AS-level routing

Proposition of an AS-level source routing algorithm
• Requirements: 1. Policy routing 2. Directional metrics
3. Pre-computation 4. Multipoint routing 5. Route diversity
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COOPERATION INCENTIVES FOR
INTEGRATED RESOURCE RESERVATION
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How to incent provider cooperation?
a Shapley value perspective

Modeling of cross-provider resource optimization
• Application of cooperative game theory to motivate it
- Shapley value: strategic weight of the importance of each player in each possible (sub)coalition
• As income distribution incentive for cross-provider added-value services
- Accounting for how much each provider has reserved resources for other providers’ services

The Shapley value can be used to assign the payoff (income) of a player (provider)
as function of its marginal contribution to the coalition. It is calculated as follows:
1. consider all the possible permutations of the providers
2. for each per mutation and each provider, calculate the marginal contribution that
the provider grants if it joins the coalition formed by the predecessor providers
3. for each provider, calculate the average of its marginal contributions on all the
permutations.
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Static reservation in Provider Alliances
a Shapley value computation example

Shapley value computation
• Starting with per-destination link reservation levels
- How much each provider in each ordered
subcoalition can guarantee? What is its
marginal contribution in terms of bw reservation?
- The weighted average is the SV
p1 = 0.5, p2 = 0.25, p3 = 0.25
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Static reservation in Provider Alliances
a Shapley value perspective

Modeling of cross-provider resource optimization
• Abstract representation of reservation levels
• From router link level toward AS-level
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Static reservation in Provider Alliances
a Shapley value perspective

Modeling of cross-provider resource optimization
• Application of cooperative game theory to motivate it
- Shapley value: strategic weight of the importance of each player in each possible (sub)coalition
• As income distribution incentive for cross-provider added-value services
- Accounting for how much each provider has reserved resources for other providers’ services
Per inter-AS link and per-flow
bandwidth reservation levels
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i = injected
t = terminated
tr = transit
Static reservation in Provider Alliances
Shapley value properties

Shapley value properties contextualized
• Symmetry
- If a provider reserve as much bandwidth as another provider for a flow, both should get the same
amount
• Efficiency
- All the revenues related to a service are shared among the providers that reserved the resources for
that service
• Null player
- If a provider reserve no bandwidth for a tunnel service, it will get zero
• Anonymity
- The name of the provider does not affect the value imputation
• Additivity
- The combination of more games (more tunnels) result in the sum of the single Shapley values
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Static reservation in Provider Alliances
a Shapley value-based revenue distribution

Fair multi-provider schemes for cost/revenue sharing
• Extension for all per-destination flows
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Related publications

S. Secci, J.-L. Rougier, A. Pattavina, M. Mycek, M. Pioro, A. Tomaszewski, "
Connection-oriented Service Management in Provider Alliances: a Shapley Value
Perspective", submitted to Euro-NF 5th Int. Workshop on Traffic Management and
Traffic Engineering for the Future Internet, 7-8 Dec. 2009, Paris, France.

M. Mycek, S. Secci, M. Pioro, J.-L. Rougier, A. Tomaszewski, A. Pattavina,
"Cooperative Multi-Provider Routing Optimization and Income Distribution", in
Proc. of 2009 7th Int. Workshop on the Design of Reliable Communication
Networks (DRCN 2009), 25-28 Oct. 2009, Washington, USA.



Interesting overview of Shapley value applications
S. Moretti, F. Patrone, Transversality of the Shapley value, Top, 16, no. 1, 1-41,
July 2008.
Technology framework paper
R. Douville, J.-L. Le Roux, J.-L. Rougier, S. Secci, "A Service Plane over the PCE
Architecture for Automatic Multi-Domain Connection-Oriented Services", IEEE
Communications Magazine, Vol. 46, No. 6, June 2008.
PhD dissertation
Stefano Secci, Multi-provider Service and Transport Architectures, Politecnico di
Milano and Télécom ParisTech - ENST, Dec. 2009
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This is the end…
QUESTIONS?
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