“Scalable and Topologically-aware Application-layer Multicast”

1. Korea Advanced Institute of Science and Technology 17th APAN meetings / Jt Techs workshop “Scalable and Topologically-aware Application-layer Multicast” 2004.1.29 Yusung Kim yskim@cosmos.kaist.ac.kr Korea Advanced Institute of Science and Technology

2. Korea Advanced Institute of Science and Technology Outline 1. Introduction 2. Related works 3. Problem definition 4. Model 5. Performance evaluation 6. Analysis 7. Conclusion 8. Future work Reference

3. Korea Advanced Institute of Science and Technology 1. Introduction : Logistical Networking • Logistical Networking is an end-to-end approach for globally scalable network storage [Beck 02] • It is applied to large-scale distributed network storage system such as web caching, FTP mirroring, Content Distribution Network (CDN), and Data Grid etc. • A scalable and efficient one-to-many data transfer mechanism is necessary when moving data to large-scale distributed nodes on Logistical Networking Logistical Backbone

4. Korea Advanced Institute of Science and Technology 1. Introduction : Application-layer Multicast • IP multicast is an efficient mechanism for multipoint data transfer, but deployment has not been widely adopted yet [Banerjee 02] • Application-layer Multicast does not change the network infrastructure, instead it implements multicast forwarding functionality at end-host. H1 H3 H1 H3 1 1 27 R1 R2 2 3 25 2 H2 H4 H2 H4 1 a. Physical network topology b. Application-layer data path Total latency : 30 Total latency : 32 H R : Host : Router Number : latency

5. Hx Hx Hx H3 H2 H4 H5 ? ? Korea Advanced Institute of Science and Technology 2. Related works - Application-layer Multicast approaches 2) Tree first approach [Zhang 02] 1) Centralized approach [Pendarakis 01] Hx H1 H2 H1 H3 H4 Hx • Using global topology information • Not scalable • Using partial topology information • Scalable H Host : multicast participant

6. H4 R4 H1 5 5 190 5 5 90 H3 R1 R2 R3 H2 5 H4 300 H1 100 200 H3 10 100 Non topologically-aware path H2 100 Topologically-aware path b. Comparison between two application-layer data paths Korea Advanced Institute of Science and Technology 3. Problem definition • Lack of global topology information cause data-paths to include unnecessary high-latency hops, it increases the usage of network resource and delays data transfer time H: Host, R: Router, Number: latency a. Physical network topology

7. L(2,3,1) L(2,1,3) Seoul Univ. H9 H11 landmark 2 JAPAN Tokyo Univ. H2 H10 landmark 1 KAIST KOREA H4 H7 H3 landmark 3 H5 L(1,3,2) H8 H6 L(3,2,1) L(3,1,2) Korea Advanced Institute of Science and Technology 4. Model • Adding landmark scheme to tree-first approach for the scalable application-layer multicast, construct topologically-aware data paths L(1,2,3) H1 Source Host : multicast participant H L ( landmark 1, landmark 2, landmark 3 ) : order of near landmarks

8. Korea Advanced Institute of Science and Technology 5. Performance evaluation5.1 Topology generation methodology

9. Korea Advanced Institute of Science and Technology 5. Performance evaluation 5.1 Topology generation methodology 5.2 Result I : link latency 5.3 Result II : path stretch 5.4 Reuslt III : number of control message * Stretch (relative delay penalty)[Chu 00] : the ratio of the delay from the source to the member along the application-layer data path, to the delay of the direct unicast path • Control messages (control overhead)[Banerjee 02] : messages exchanged between all nodes to construct data path

10. Korea Advanced Institute of Science and Technology 5.2 Result I : link latency - on Logistical Backbone experiment Unicast Tree first approach Landmark based approach Centralized approach • less average link latency than that of tree first approach Comparison on average link latency ( with 6 landmarks )

11. Korea Advanced Institute of Science and Technology 5.2 Result I : link latency - on Inet simulation Unicast Tree first approach Landmark based approach Centralized approach IP multicast • less average link latency than that of tree first approach Comparison on average link latency (with 20 landmarks)

12. Korea Advanced Institute of Science and Technology 5.3 Result II : path stretch - on Inet simulation Tree first approach Landmark based approach Centralized approach • significantly reduced average path stretch Comparison on average path streth (with 20 landmarks)

13. Korea Advanced Institute of Science and Technology 5.4 Result III : number of control messages - on Inet simulation Tree first approach Landmark based approach Centralized approach • Case of receivers above 30, the number of control messages of landmark based approach is similar to that of tree first approach Comparison on number of control messages (with 20 landmarks)

14. Korea Advanced Institute of Science and Technology 6. Analysis

15. Korea Advanced Institute of Science and Technology 7. Conclusion + Contribution 1) We applied landmark scheme to Tree first approach 2) In results of performance evaluation, Landmark based approach can reduce the average link latency and path stretch of Tree first approach 3) Landmark based approach needs the constant number of landmarks and low number of control messages as much as Tree first approach does => Landmark based approach can offer the scalability of tree first approach and construct the topologically-aware data paths using landmarks. Using topologically-aware paths, we can reduce bandwidth consumption and data transfer time + Limitation => An additional landmark infrastructure is necessary

16. Korea Advanced Institute of Science and Technology 8. Future work • Existing researches for application-layer multicast considered network latency to construct data pathsBandwidth-awareness is also important to construct data paths 1 ms 100 Kbps H2 H1 H3 100 ms 1 Gbps H Host

17. Reference Akamai, http://www.akamai.com (Accessed: 8 December 2003). S. Banerjee, B. Bhattacharjee, and C. Kommareddy, "Scalable application layer multicast," in Proc. ACM SIGCOMM, Pittsburgh, PA, USA, August 2002. M. Beck, T. Moore, and J. Plank, "An end-to-end approach to globally scalable network storage,“ in Proc. ACM SIGCOMM, Pittsburgh, PA, USA, August 2002. M. Faloutsos, P. Faloutsos, and C. Faloutsos, “On power-law relationships of the Internet topology,” in Pro. ACM SIGCOMM , Cambridge, MA, USA, September 1999. Inet, http://topology.eecs.umich.edu (Accessed: 8 December 2003). J. Jannotti, D. K. Gifford, K. L. Johnson, M. F. Kaasheok, and J. W. O’Toole, “Overcast: reliable multicasting with an overlay network,” in Proc. 4th USENIX OSDI, San Diego, CA, USA, October 2000. Lbone, http://loci.cs.utk.edu (Accessed: 9 December 2003). D. Pendarakis, S. Shi, D. Verma, and M. Waldvogel, “ALMI: an application level multicast infrastructure,” in Proc. 3rd USENIX Symp. Internet Tech. and Sys., San Francisco, CA, USA, March 2001. S. Ratnasamy, M. Handley, Richard Karp, and S Shenker, “Topologically-aware overlay construction and server selection,” in Proc. IEEE INFOCOM, New York, NY, USA, June 2002. B. Zhang, S. Jamin, and L. Zhang, “Host multicast: a framework for delivering multicast to end users,” in Proc. IEEE INFOCOM, New York, NY, USA, June 2002. [Akamai] [Banerjee 02] [Beck 02] [Faloutsos 99] [Inet] [Jannotti 00] [Lbone] [Pendarakis 01] [Ratnasamy 02] [Zhang 02]

18. Appendix : number of control messages- on Logistical Backbone experiment Tree first approach Landmark based approach Centralized approach

19. tree-first landmark based centralized IP multicast Appendix : link stress * stress: defines the stress of a physical link as the number of identical packets it carries

20. Appendix: path stretch Tree first approach Tree first approach Landmark based approach Landmark based approach Centralized approach Centralized approach b. average path stretch on Inet a. average path stretch on Logistical Backbone

21. Appendix: metric [Chu 00] • Stress: defines the stress of a physical link as the number of identical packets it carries • Stretch: is the ratio of the delay between a source and a member along the overlay distribution topology, to the delay of the direct unicast path • Resource usage: defines this metric as the sum of the delay * stress product over all the links that participate in data transmissions