Active reliable multicast strategies for Internet-based grid computing infrastructures

1. Active reliable multicast strategies for Internet-based grid computing infrastructures M. Maimour & C. Pham

2. What is a computational grid? application user from Dorian Arnold: Netsolve Happenings

3. Some grid applications Astrophysics: Black holes, neutron stars, supernovae Mechanics: Fluid dynamic, CAD, simulation. Distributed & interactive simulations: DIS, HLA,Training. Chemistry&biology: Molecular simulations, Genomic simulations.

4. What is reliable multicast? Sender • Not n-unicast from the sender perspective • Efficient one-to- many data distribution • No data losses data data data data Receiver Receiver Receiver

5. Examples data & program distribution collective & gather operations synchronization barriers SDSC IBM SP 1024 procs 224.2.0.1 NCSA Origin Array 256+128+128 procs CPlant cluster 256 nodes application user Multicast address group 224.2.0.1

6. What is active networks? • Programmable nodes/routers • Customized computationson packets • Standardized execution environment and programming interface • No killer applications, only a different way to offer high-value services, in an elegant manner • However, adds extra processing cost

7. Motivations behind active networking • user applications can implement, and deploycustomized services and protocols • specific data filtering criteria (DIS, HLA) • fast collective and gather operations… • globally better performances by reducing the amount of traffic • high throughput • low end-to-end latency

8. data data Active networking illustrated • Specific code can be applied on the packet • Integrated and discrete approaches • High flexibility to define new services data

9. where to put active components? 1000 Base TX active router active router core network Gbits rate Server active router active router 100 Base FX active router

10. NACK4 Active local recovery • routers perform cache of data packets • repair packets are sent by routers, when available data data data5 data1 data2 data1 data3 data2 data4 data3 data5 data4 data5 data4 data1 data2 data3 data5

11. NACK4 NACK4 data4 NACK4 NACK4 only one NACK is forwarded to the source by the router: global NACK suppression NACK4 Active feedback aggregation • Routers aggregate feedback packets

12. data4 NACK4 data4 NACK4 data4 data4 data4 NACK4 data4 data4 NACK4 data4 data4 data4 data4 Active subcast features • Send repair packet only to the relevant set of receivers

13. Network model F active routers among N. B receivers in a local group 2 kinds of receivers: linked and free

14. Active reliable multicast strategies • S1 : global NACK suppression • S2 : local NACK suppression • S2S : + subcast from the source • S3 : global NACK suppression subcast from the routers • S3S : + subcast from the source

15. Analysis preview

16. Benefit of global aggregation on throughput S1

17. Benefit of the source subcast facility S2S/S2

18. Impact of active router density S3

19. Conclusions • Efficient reliable multicast protocols are a big win for grid applications • Active networking can really help enhancing the reliable multicast performances • global NACK suppression is easy to implement, and allows subcast from routers • local NACK suppression performs well for high loss rates but is difficult to tune • subcasting is very interesting when the number of receivers is large