FARA: Reorganizing the Addressing Architecture

1. FARA: Reorganizing the Addressing Architecture David Clark, Robert Braden, Aaron Falk, Venkata Pingali ACM SIGCOMM 2003 Workshops August 25&27, 2003 2005.09.07 Jongsoo Lee (jslee@mmlab.snu.ac.kr)

2. Content • Introduction • Abstraction, Modularity and Simplicity • FARA • M-FARA • Conclusion

3. Abstraction, Modularity and Simplicity Node Identity ↕ Network Location • Abstraction • Modularity • Simplicity 147.46.114.112 mmlab.snu.ac.kr Seoul University

4. Content • Introduction • FARA • Components • Functions • The System Model • M-FARA • Conclusion

5. Components E2 E1 API Communication substrate • Entity • Generalization of an application • Maintain application state & communication state • Association • Logical communication link • Combination of communication state & flowing data • Communication Substrate • Deliver data on behalf of associations • Using Forwarding Directive (FD) a • The smallest mobility unit & no global set of names • No global namespace • No single global address space Assumptions a • No new global namespace of entity name! • How do associations get established when there is no global • namespace for entities? • How are packet delivery paths maintained as entities move?

6. Functions • Creating an Association • Rendezvous Mechanism • Not dest AId, Rendezvous information (RI) in initial packet • Discovery & Initiation • FARA Directory Service (fDS) • Single generic directory service • RI → FD • End-to-End Security • Support a range of source verification mechanisms, ranging from nothing to high security • Assurance level ↑→ overhead, complexity and latency ↑

7. Functions • Communication Substrate Mechanisms • Packet Delivery • Connectionless best-effor packet delivery is basic • allow wide range architecture • FD Management • use API for manipulation and signaling • Mobility support • Network-Layer Security • Use own notion of identity (different from identity of upper-layer) • Delivery Failure Notification • Resource Control

8. Functions • Forwarding Directive • Uniform and well-defined syntax • Derived from the network topology • Network part + local-delivery (slot ID) part → FD • May contain identifiers drawn from a global address space • May be reversible • May be transformed in route • Slots • A logical point of attachment of the entity to the network topology • The place to which an FD directs packet delivery and in which an entity is located

9. The System Model User level Slot OS level FD1 FD2 You can use another model! ENTITY AId1 AId2 AId3 AIdn Association State . . . Communication Substrate • Entity Start up • Request slot • Get own FD • If the entity provides a service, Register a (service → FD) with the fDs

10. Content • Introduction • FARA • M-FARA • Overview • Implementation • Conclusion

11. Overview • Network Addressing • Destination FD is independent of the topological location. • 2-level domain hierarchy – (FDup, FDdown) • FDup : from source to global routabledomain • FDdown : from global domain to destination • FD Maintenance • Using Mobility Agents (M-agents) • Indirection or Redirect message • Associations • Simple (similar with UDP) • + authorization (similar with DCCP) →Connected • + mobility →Mobile • + reliability & ordering →Reliable (similar with TCP) M agent

12. Low-level end-system : UNIX processes using UNIX IPC Communication via Internet overlays with UDP Routing Hop-by-hop forwarding & Source Routing FD form (HopFD1, HopFD2, …, SlotID) HopFD : IPv4 or IPv6 address Implementation

13. Content • Introduction • Abstraction, Modularity and Simplicity • FARA • Components • Functions • The System Model • M-FARA • Overview • Implementation • Conclusion

14. Conclusion • Although concepts are not new, assembly into a general model is new! • Modularized 2-level architecture • Upper-level : abstractions of entities and associations • Lower-level : communication substrate • Separation location from identity • Provide support for general mobility • Independent evolution of mechanisms at the two level • FARA is a work in progress