2. Web Server Distributor1 Lecturer: Dr. Reuven Cohen Lab Engineer: Eng. Itai Dabran Project Supervisor: Daniel Segal Authors: Rony Fuks Yossi Peery Gil Sasson Fall 2000/1 Computer Science Department Technion- Israel Institute of Technology The Laboratory of Computer Communications and Networking

3. Web Server Distributor2 Motivations High Performances E-Commerce, B2B, B2C, DotCom Hardware Technology Vs. Internet Growth How to Distribute ? Answer …… Web Server Distributor

4. 3 Theory

5. Web Server Distributor4 Types of Load Balancers Hardware NetworkSoftware

6. Web Server Distributor5 Server Monitoring Internal Monitoring Internal Monitoring External Monitoring  ICMP  TCP  HTTP

7. Web Server Distributor6 Server Selection  Round Robin  Response Time Based Decision  Sophisticated Algorithms

8. Web Server Distributor7 Our Project

9. Web Server Distributor8 Load Balancer File Table WS Table Decision Algorithms Updates Sampler... WS 1 HTTP Client WS n HTTP Client GET => <= REPLY GET => <= REPLY Redirector Worker Thread Completion Port Loop OP ACCEPT OP RECV new HTTP connects HTTP redirect URI => <=Server IP GUI Our Project

10. Web Server Distributor9 Our Project Redirector  Simple HTTP server  Using IO completion ports  Multi Threaded

11. Web Server Distributor10 Our Project GUI

12. Web Server Distributor11 Our Project GUI MFC GUI MFC GUI  Communication with the load balancer and the redirector through message tunneling

13. Web Server Distributor12 Our Project Sampler Algorithm  Sampling algorithm  Completed transaction  Incomplete transaction  No Response

14. Web Server Distributor13 Our Project Sampler Code Structure  Thread Creation/Destruction  HTTP “GET” request  Time measurement  Sampling Ratio  Updating Interface

15. Web Server Distributor14 Our Project Load Balancer  File Table  Sampling List  Web Server Table  Decision Algorithm

16. Web Server Distributor15 Our Project Load Balancer File Table Input  ini file 1. URI 2. File Size 3. Server Location Output  Hash Table

17. Web Server Distributor16 Our Project Load Balancer Sampling List How to check WS ?  Same File on Each WS  Go over hash table  Find all files that exist on all WS

18. Web Server Distributor17 Our Project Load Balancer Web Server Table WSIIPNo. Get Resp. Time RankAvg. Rank Weighted Rank No. Time Out Cont. Time Out B. Sent[1] B. Sent[2] B. Sent[3] B. Sent[4] Max Capac ity 0 132.68.37.6057 2011.25 0 0 2000 10002541 45530000 1 132.68.37.61573022.645 0 012543212145145550000 2 132.68.37.62572613.258.542 0654487459574457680000 3 132.68.37.6357Inf. 4.47Inf.1 0159841252255214521000 4 132.68.37.64572211.555.684 012546987120014715000 5 132.68.37.6557Inf. 1.34Inf.3 32365154752025412000 6 132.68.37.66574031.248.975 01025122510014000

19. Web Server Distributor18 Our Project Load Balancer Web Server Table Ranking Process  Results from Sampler (wait till time out) What if we didn’t receive all the file ?  Find lowest response time  Find range (lowestXfactor)  Find next range (etc`) WSIIPResp. Time Rank 0 132.68.37.60 201 1 132.68.37.61302 2 132.68.37.62261 3 132.68.37.63Inf. 4 132.68.37.64221 5 132.68.37.65Inf. 6 132.68.37.66403

20. Web Server Distributor19 Our Project Load Balancer Web Server Table WSIIPResp. Time RankNo. Time Out Cont. Time Out 0 132.68.37.60 2010 0 1 132.68.37.613020 0 2 132.68.37.622612 0 3 132.68.37.63Inf. 1 0 4 132.68.37.642214 0 5 132.68.37.65Inf. 3 3 6 132.68.37.664035 0 Time Outs  No. of time outs  Cont. Time outs

21. Web Server Distributor20 Our Project Load Balancer Web Server Table Bytes Sent Calculation  Dividing the bytes sent by periods WSIIPB. Sent[1] B. Sent[2] B. Sent[3] B. Sent[4] Max Capac ity 0 132.68.37.60 2000 10002541 45530000 1 132.68.37.6112543212145145550000 2 132.68.37.62654487459574457680000 3 132.68.37.63159841252255214521000 4 132.68.37.6412546987120014715000 5 132.68.37.652365154752025412000 6 132.68.37.661025122510014000

22. Web Server Distributor21 Our Project Load Balancer Web Server Table Dividing the bytes sent by periods What is the logic behind What is the logic behind Calculations of Clients Distributions TimesCalculations of Clients Distributions Times Time Line 0-150-100-50

23. Web Server Distributor22 Our Project Load Balancer Web Server Table Weighted Rank Calculations Weighted Rank = (F1 X Rank + F2 X Average Rank + F2 X Average Rank + F3 X No. Time Out + F3 X No. Time Out + F4 X Cont. Time Out ) + F4 X Cont. Time Out ) + (B1 X B.Sent[1]/Max Capacity + B2 X B.Sent[2]/Max Capacity + B2 X B.Sent[2]/Max Capacity + B3 X B.Sent[3]/Max Capacity + B3 X B.Sent[3]/Max Capacity + B4 X B.Sent[4]/Max Capacity ) B4 X B.Sent[4]/Max Capacity )

24. Web Server Distributor23 Our Project Load Balancer Decision Algorithm Best Server Function Find lowest weighted rank Update weighted rank/Bytes sent If lowest weighted rank =  If Continuous Time Out  MaxContTimeOut Return Null If Continuous Time Out < MaxContTimeOut Return Redirector IP

25. Web Server Distributor24 Our Project FIN