1. Virtual Organizations in the Arigatoni Overlay Network Luigi Liquori INRIA, France Luigi.Liquori@inria.fr Raphael Chand INRIA, France Raphael.Chand@inria.fr Michel Cosnard INRIA, France Michel.Cosnard@inria.fr

2. Virtual Organizations in the Arigatoni Overlay Network — L. Liquori et al.2 Talk Outline Context and Arigatoni Model Arigatoni’s Intermittence Rewriting Semantics (a bit of) Arigatoni’s Resource Discovery Arigatoni’s Protocol Evaluation Conclusion and what’s next

3. Virtual Organizations in the Arigatoni Overlay Network — L. Liquori et al.3 Context: Global Computing Global Computing Communication Paradigm: computation via a seamless, geographically distributed, open-ended network of bounded resources owned by ”Individuals” Examples Internet (IP graph, a.k.a. “the backbone”, sharing) Telephone Network (Overlay with QoS) GRID (computing power sharing) P2P (data sharing) VoIP (band sharing) Web services (“semantic infos” sharing)

4. Virtual Organizations in the Arigatoni Overlay Network — L. Liquori et al.4 Context: Overlay Networks Challenges Virtual Organizations of Individuals Resource Discovery between Individuals (of course … Security, Scalability, Reliability, and tutti frutti …) Virtual Organization (Colony) How individuals organize themselves to share resources transparently How the organization evolves in time and in space transparently Resource Discovery How single resources, offered by individuals, are discovered How changed states of resources are upgrated in routing tables … The Arigaroni Overlay Network (©INRIA)

5. Virtual Organizations in the Arigatoni Overlay Network — L. Liquori et al.5 Global Computers, Brokers, Routers Global Computers (GCU) Device of any size (GSM, PDA, Laptop, …, Cluster of PCs, …) Discontinuous participation in the Virtual Organization (Colony) Partial/Zero knowledge of the current Virtual Organization Ask and provide services with variable guarantees Can work in Local Mode or in Global Mode Motto: Global Mode … ask to the Colony boss, and wait for the best …if the Colony boss ask for something do your best … Global Brokers (GBU) Colony’s leader, but just individual in a surrounding “SuperColony” Register/Unregister GCU in the own colony Send/Receive GCU’s queries Contact GCUs in its population or contact its direct SuperGBs Trust their population at any level of the negotiation (via e.g. PKI) Global Routers (GRU) Send/Receive Packets via a protocol (GIP) between GCU and GBU

6. Virtual Organizations in the Arigatoni Overlay Network — L. Liquori et al.6 Arigatoni Overlay Network Topology Arigatoni, Overlay Network composed by Colonies and SubColonies Global Brokers (GBU) = Routing queries (un/register, resource discovery) Global Computers (GCU) = Ask/provides resources interchangeably Global Router (GRU) = Dispatch packets around the network Hierarchical tree structured organization Once the resource/s is/are negotiated, GCUs communicate in P2P fashion GB GB 1 GB n … GC k GC 1 … Leader Individuals Colony GB Leader GC k GC 1 … GC k GC 1 … SubColony ……

7. Virtual Organizations in the Arigatoni Overlay Network — L. Liquori et al.7 Syntax: Colonies and Communities Colony syntax Community (Soup) syntax

8. Virtual Organizations in the Arigatoni Overlay Network — L. Liquori et al.8 Syntax Examples

9. Virtual Organizations in the Arigatoni Overlay Network — L. Liquori et al.9 Cardelli and Gordon Ambients … “In the early days of the Internet one could rely on a flat name space given by IP addresses; knowing the IP address of a computer would very likely allow now to talk to that computer in some way. This is no longer the case: firewalls partition the Internet into administrative domains that are isolated from each other except for rigidly controlled pathways. System administrators enforce policies about what can move through firewalls and how [...]”

10. Virtual Organizations in the Arigatoni Overlay Network — L. Liquori et al.10 Arigatoni: Registration Modalities Registration of a GCU to the GBU leader of a colony belonging to the same current administrative domain of the GCU Registration via remote tunneling of an GCU to another GBU leader of a colony belonging to a different administrative domain of the GCU Summarizing, one GCU register to the GBU leader of the colony belonging to the same administrative domain in which it resides and to some other GBUs via tunneling

11. Virtual Organizations in the Arigatoni Overlay Network — L. Liquori et al.11 Arigatoni: Unregistration Modalities Unregistration of a GCU when there are no pending services demanded or requested to the leader GBU of the colony it belongs. The colony accepts the unregistration only if the colony itself will not be corrupted A GBU cannot unregister from its own colony (i.e. it cannot discharge itself). For fault tolerance purposes, a GBU can be faulty. In that case, the GCUs will unregister one after the other and the colony will “disappear” Once a GCU has been disconnected from a colony belonging to any administrative domain, it can migrate in another colony belonging to any other administrative domain (“emigrant” model)

12. Virtual Organizations in the Arigatoni Overlay Network — L. Liquori et al.12 Arigatoni Overlay Network@glance

13. Virtual Organizations in the Arigatoni Overlay Network — L. Liquori et al.13 GCU’s Registration Unregistration A GCU join a Colony A GCU leave a Colony

14. Virtual Organizations in the Arigatoni Overlay Network — L. Liquori et al.14 COL’s Registration Unregistration Colony Registration Colony Unregistration

15. Virtual Organizations in the Arigatoni Overlay Network — L. Liquori et al.15 Colonies not in the Same Domain Linking two Colonies UnLinking two Colonies

16. Virtual Organizations in the Arigatoni Overlay Network — L. Liquori et al.16 Contextual and Congruence Morris like rules

17. Virtual Organizations in the Arigatoni Overlay Network — L. Liquori et al.17 Join/Leave a Colony in a Different Administrative Domain Individual in IP1 knows “friends” inhabitant of the colony in IP2. Then, via an explicit ssh the laptop can log into the desktop and send a global request to the “mother colony”. As such, the laptop works in its local mode while the desktop works in global mode. No ad hoc rewriting rules in the Arigatoni virtual organization Individual in IP1 knows no inhabitant of the colony in IP2, but it knows the address of the leader of the colony. Via ssh-tunnel a virtual clone of the remote individual on behalf of the leader of the colony is created and registered. As such, the laptop works in local mode while the clone works in global mode. This mechanism is reminiscent of the Virtual Private Network technology (VPN). We need 4 Extra Rewriting Rules

18. Virtual Organizations in the Arigatoni Overlay Network — L. Liquori et al.18 GCU not in the Same Domain

19. Virtual Organizations in the Arigatoni Overlay Network — L. Liquori et al.19 Colonies not in the Same Domain

20. Virtual Organizations in the Arigatoni Overlay Network — L. Liquori et al.20 Free Riders in Overlay Networks In economics and political science, free riders are actors who consume more than their fair share of a resource, or shoulder less than a fair share of the costs of its production … The free rider problem is the question of how to prevent free riding from taking place, or at least limit its negative effects … Because the notion of “fairness” is a subject of controversy, free riding is usually only considered to be an economic “problem” when it leads to the non-production or under- production of a public good, and thus to Pareto inefficiency, or when it leads to the excessive use of a common property resource. [From Wikipedia].

21. Virtual Organizations in the Arigatoni Overlay Network — L. Liquori et al.21 Arigatoni Rules to “Fire” Free Ridings

22. Virtual Organizations in the Arigatoni Overlay Network — L. Liquori et al.22 GC issues service request to the system via its GB leader The GB finds “some” GCs able to serve the request using an O.O. lookup Report “some” GCs that accepted to serve it GC talks with the GCs in a P2P fashion Simple Constraint Language + First-order Matching algos à la Nancy’s Rho-calculus Arigatoni [Type = CPU] [Time < 10s] [Type = CPU] [Time < 10s] [Type = CPU] [Type < 20s] [Type = CPU] [Type < 20s] [Type = CPU] [Mem < 10M] [Type = CPU] [Mem < 10M] [Type = CPU] [Time > 5s] [Type = CPU] [Time > 5s] Service Request GC A S’ S1S1 S2S2 S3S3 GC B GC C Glance of Resource Discovery Protocol I2CS, Neuchatel, June 06, LENS

23. Virtual Organizations in the Arigatoni Overlay Network — L. Liquori et al.23 Glance of Resource Discovery Protocol I2CS, Neuchatel, June 06, LNCS S = [Type = CPU] & [Time > 10s] Selective intra-colony search mode uses less resources can lead to poor delay Exhaustive search mode uses more resources can improve delay A C E D FGH GC 1 GC 2 [Type = CPU] [Time < 200] [Type = CPU] [Time < 200] S2S2 [Type = MEM] [Capa < 20] [Type = MEM] [Capa < 20] [Type = CPU] [Time < 20] [Type = CPU] [Time < 20] S1S1 GC 3 S3S3 [Type = CPU] [Time > 10] [Type = CPU] [Time > 10] Selective intra-colony searchExhaustive intra-colony search B

24. Virtual Organizations in the Arigatoni Overlay Network — L. Liquori et al.24 Experimental Evaluation Sample Topology GeorgiaTech-ITM (transit-stub)

25. Virtual Organizations in the Arigatoni Overlay Network — L. Liquori et al.25 The Rationale of the Simulation We start with a fully connected topology The rationale is apply a number of rewriting rules de/connecting GCU/GBU from the topology and then do the experiment We study the impact of the disconnections using a variable   [0..100]%

26. Virtual Organizations in the Arigatoni Overlay Network — L. Liquori et al.26 Average Acceptation Ratio a

27. Virtual Organizations in the Arigatoni Overlay Network — L. Liquori et al.27 Service Acceptation Ratio b

28. Virtual Organizations in the Arigatoni Overlay Network — L. Liquori et al.28 Standard Deviation of Accept Rate

29. Virtual Organizations in the Arigatoni Overlay Network — L. Liquori et al.29 Real Example in a Grid Arena

30. Virtual Organizations in the Arigatoni Overlay Network — L. Liquori et al.30 In Fine… Arigatoni: Lightweight Overlay Network for dynamic Resource Discovery. Achievements Intermittence Generality Asynchronicity Scalability Current, future work More functionalities (service instances, conjunctions) Statistical model of the framework Protoimplementation,deployment (PlanetLab,G5000)

31. Virtual Organizations in the Arigatoni Overlay Network — L. Liquori et al.31 Questions?

32. Virtual Organizations in the Arigatoni Overlay Network — L. Liquori et al.32 Resource Discovery Protocol Routing tables maintained at each GB ⇒ set of services registered in each Colony Always search in own colony first: encapsulation Local colony of GCs Other sub-colonies in Colony Other Colonies via the GB leader = OO delegation- based Service request for service S’ Search GCs in local colony that accept to serve S’ Search in other sub-colonies If none are found, delegate to the leader GB … Looks much like “method lookup” in OO languages…

33. Virtual Organizations in the Arigatoni Overlay Network — L. Liquori et al.33 Context: Overlay Networks Physical Network Overlay Network A B C Focus on the application layer Treat multiple hops through IP network as one hop in an overlay network

34. Virtual Organizations in the Arigatoni Overlay Network — L. Liquori et al.34 Resource Discovery Protocol

35. Virtual Organizations in the Arigatoni Overlay Network — L. Liquori et al.35 Resource Discovery Protocol (Sketch) Type=CPU Time>10 Type=CPU Time>10 Type=MEM Capa < 20 Type=MEM Capa < 20 S3S3 GC 3 A C B E D FGH GC 1 GC 2 Type =CPU Time<200 Type =CPU Time<200 S2S2 Type=CPU Time < 20 Type=CPU Time < 20 S1S1 Encapsulation of resources in colonies Always search in colony first Delegate if no GCs are found ⇒ prevents super brokers from begin overloaded