The Implication of Overlay Routing The Implication of Overlay Routing on ISPs’ Connecting Strategies Graduate School of Information Science and Technology, Osaka University Xun Shao, Go Hasegawa, Yoshiaki Taniguchi, and Hirotaka Nakano
IP layer routing and overlay routing 2 � Overlay routing may Application Layer change IP routing at application layer to better satisfy the better satisfy the IP Layer applications’ demands � Overlay routing may violate ISPs’ routing policies Non-overlay node Overlay node ITC2011 2011/9/8
Tiered Internet architecture 3 Tier-1 ISP Tier-2 ISP Local ISP Transit relation Peering relation Peering relation � Transit relationship: Transit traffic from (to) customer ISPs to (from) every where � Peering relationship: Only exchange peering ISPs’ local traffic � Bill-and-Peer (BK) peering: No money exchange between peering ISPs � Paid peering: One ISP should pay for the other according to agreement ITC2011 2011/9/8
Related researches 4 � Researches on overlay routing � Performance improvement of overlay networks [1] � Researches on ISPs’ peering settlement � Peering of asymmetric ISPs [2] � Hot /Cold-potato routing [3] Hot /Cold-potato routing [3] � An open issue � How does overlay routing affect ISPs’ peering settlement? [1] Z. Duan, Z. L. Zhang and Y. T. Hou, “Service Overlay Networks: SLAs, QoS, and Bandwidth Provisioning,” IEEE/ACM Transactions on Networking, vol. 11, pp. 1-10, 2003 [2] E. Jahn and J. Prüfer, “Interconnection and Competition Among Asymmetric Networks in the Internet Backbone Market,” Information Economics and Policy, vol.20, pp. 243-256, 2006 [3] G. Shrimali and S. Kumar, “Paid Peering Among Internet Service Providers,” Proc. GameNets Workshop on Game Theory for Communications and Networks, 2006
Network and business models 5 � ISPs’ monetary costs � Transit cost of per unit traffic for ISP i : P i � Peering cost of per unit traffic (only for ＄ :P B ＄ :P paid peering): A ＄ :p AB > 0, if ISP A pays ISP B p p < 0, if ISP pays ISP < 0, if ISP B pays ISP AB A = 0, reduced into BK peering Link capacity � ISPs’ latency cost D( c , t ) � Latency function of one link: Traffic between i and j Traffic through the link tD( c , t ) � Latency cost of that link: � ISPs’ combined cost � Monetary cost + γ (Link latency cost) Traffic between i and j A parameter translating latency cost to monetary cost
ISPs’ costs with no peering and BK peering 6 � ISPs’ costs without peering NP = γ + + + + J t t D t t P t t ( ) ( ) ( ) A AR AB AR AR AB A AR AB NP = γ + + + + J t t D t t P t t ( ) ( ) ( ) B BR AB BR BR AB B BR AB � ISPs’ costs with BK peering ISPs’ costs with BK peering ~ ~ ~ ~ ~ BK = γ + α + J t D t t D t P t ( ( ) ( )) A AR AR AR AB AB AB A AR ~ ~ ~ ~ ~ BK = γ + − α + J t D t t D t P t ( ( ) ( 1 ) ( )) B BR BR BR AB AB AB B BR R t ij : The traffic demand between i and j ~ : The actual traffic amont through link l AB t ij α : The dependence of ISP A on link l AB ? A B
ISPs’ costs calculation with paid peering 7 � Nash bargaining solution � Fair and Pareto optimal � ISPs’ costs with paid peering can be got from Nash Bargaining Bargaining Paid peering cost ~ PP = BK + J J p t * A A AB AB ~ PP = BK − J J p t Bargaining power of ISP * A B B AB AB α − α = NP − PP NP − PP p J J J J 1 arg min( ) * ( ) AB A A B B
Overlay traffic patterns vs. peering levels 8 1. Peering capacity is of low 3. Peering capacity is of level high level R R D AB =D AR +D BR D AR =D AB +D BR Capacity Capacity Capacity A A B B A A B B is low is low is high The multi-hop overlay traffic in case 3 is also called “ free-riding ” 2. Peering capacity is of me- traffic dium level R D AB <=D AR +D BR Multi-hop overlay traffic D AR >=D AB +D BR We assume that: D AR ( t AR ) >D BR ( t BR ) Capacity A B is medium
An example of ISPs’ costs vs. peering link capacity 9 Numerical example settings variable � Latency function of each link � 1 = + D 0 . 001 ~ Low Medium High AB � − c t M/M/1 AB AB level level level 1 link = + D 0 . 003 ~ AR � − t latency latency 500 . 0 AR AR model 1 = + D 0 . 001 ~ � BR − t 900 . 0 BR Traffic amount of each link � � t AR = 300.0, t BR = 300.0, t AB = 100.0 Overlay traffic proportion � � ρ = 0.7 Bargaining power of ISP A � � α = 0.5 ITC2011 2011/9/8
Incentives of upgrading peering link with BK peering 10 � ISP A always has incentive to upgrade the peering link when the peering level is medium or high BK dJ < A i.e. , if c AB is in medium or high range 0 dc dc AB AB � ISP B always has incentive to upgrade the peering link when the peering level is medium BK dJ < B , if c AB is in medium range i.e. 0 dc AB ITC2011 2011/9/8
Incentives of upgrading peering link with paid peering 11 � Both ISPs always have incentive to upgrade the peering link when the peering level is low or medium PP PP dJ dJ dJ dJ < < < < A A B B i.e. i.e. , if c , if c AB is in low or medium range 0 0 0 0 and and is in low or medium range dc dc AB AB � With BK peering, no ISP prefers peering with low level � With BK peering, ISP A prefers higher peering capacity than ISP B � Paid peering provides a better solution when peering level is low ITC2011 2011/9/8
Conditions in which BK peering is better than no peering 12 � For ISP A : The maximum cost when c AB is of low level BK J � A BK < NP J J � If , BK peering is better than no peering A A with arbitrary c AB in all levels AB � For ISP B BK J : The maximum cost when c AB is in low level � B BK < NP J J � If , BK peering is better than no peering B B with c AB in low or medium level ITC2011 2011/9/8
Conditions in which paid peering is better than no peering 13 � For both ISPs � Paid peering is better than no peering with arbitrary c AB in low and medium level � Free-riding traffic might cause the cost of ISP B unexpected as well as the total cost of the two ITC2011 2011/9/8
Regime equilibria 14 � Bilateral Nash Equilibrium (BNE) � At BNE, no player or a pair of players can deviate and benefit from the deviation � Strategies of ISPs Strategies of ISPs � S i ={NP, BK, PP} � {NP,NP} is default output, if ISPs prefer different strategies ITC2011 2011/9/8
Regime equilibria 15 � BNE results BK > J total � If J total NP , (NP,NP) is the only strategy of BNE � Else if � ( J A BK -J A NP )( J B BK -J B NP ) >0 , (BK,BK) and (PP,PP) are two strategies of BNE � ( J A BK -J A NP )( J B BK -J B NP ) <0 , (PP,PP) is the only strategy in BNE Paid peering is always BNE if peering level is low or medium ITC2011 2011/9/8
Summary and future work 16 � Obtained the overlay routing traffic patterns with a simple network model, and revealed the relation between traffic patterns and peering levels Showed that with BK peering, the ISP that may free-ride the � other prefers peering with medium and high level, while the ISP being free-ridden prefers only medium level � With paid peering determined by Nash bargaining solution, it is With paid peering determined by Nash bargaining solution, it is preferred by both ISPs with peering of low and medium level � Proposed a regime equilibria analysis with BNE theory, and showed that paid peering by Nash bargaining is always a BNE strategy when peering is of low and medium level � In the future, we are planning to study the implication of overlay routing on ISPs’ connection strategies in a more general network ITC2011 2011/9/8
17 Thank you very much ! ITC2011 2011/9/8
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