Load-balancing and scalability enabled by middleware

Transcription

1 Load-balancing and scalability enabled by middleware Bertrand MATHIEU / Laurent REYNAUD FTR&D/DAC/LIP/OSM 14 March

2 Introduction Use middleware for load-balancing and scalability features ÕChoice : Jini : one of «Internet Appliances» in a demanding environment (like Telecommunications) ÕChoice : a WAP Gateway Objective : Implement a WAP Gateway with Jini mechanisms to make it scalable. 2

3 Why distributing a WAP gateway? Unpredictable traffic load => greater risks for the gateway to get overloaded, and for the deployed services to get interrupted (e.g. NTT DoCoMo i-mode service troubles with the increasing of users) an emergency re-dimensioning is likely to become costly =>Where to seek flexibility? Buy platforms that bear n00% temporary overload (n=2,3,4, ) : expensive, temporary... Rethink the gateway computing architecture, enabling component distribution 3

4 Jini main features (1) Automatic discovery and registration in a hot-plug environment One component, when started, registers to the «Lookup server» (multicast request) and is then available Repository C1 T2 : Make C1 description available to other services T1 : Export C1 methods description LS Java/Jini layers T3: Ask for a given service description T5: Intercomponent direct communication T4: According to C2 criteria, SL sends C1 description C2 4

5 Jini main features (2) Zero Administration Jini «leasing» messages between components and the «Lookup server» enables this latter to know the state of every component. => Fault-Tolerance achieved Load Balancing and scalability Provided by Jini mechanisms inside the «Lookup server» : just to implement the most appropriate load balancing policy (Random, Round Robin ) 5

6 What is a WAP Gateway 2 main components FEC (Front End Component) : Receives incoming calls and sends back replies Manages contexts for every session BEC (Back End Component) : Converts WAP protocol to HTTP protocol Communicates with the Web server (WML Content) Compiles the WML data 6

7 Architecture of our WAP Gateway FEC : Front End Component BEC : Back End Component CSDR : Circuit Switch Data Router Repository BEC Toward CSDR FEC LS BEC Toward WML server Toward WML server Gateway components Jini messages Socket Jini s Lookup Service 7

8 Our WAP traffic generator Aims to test the robustness and the performance of WAP gateways Can generate X simultaneous calls (simulating access to the WAP gateway) in mode burst or linear response time logged in a file (CSV) 2 kinds of WML files available short (150 bytes) and long files (1300) 8

9 The GUI 9

10 Tests of our Jini-inside WAP gateway Simulation of 1, 5, 10, 20, 30, 50 simultaneous clients 1st case : 1 BEC running on 1 PC (the same as the FEC and the Jini Lookup server) 2nd case : 2 BECs running on 2 PCs (the 2nd BEC alone on 1 PC) 10

11 Results Good scalability because the evolution of response times is linear Response times more than twice better when 2 PCs used! 1 - Short Files 1 - Long Files Response Time (ms) _PC 2_PCs Response Time (ms) _PC 2_PCs Nb of calls / sec Nb of calls / sec 11

12 Demonstration Distribute the load between several computers (with the help of the Jini mechanisms : dynamic discovery, load-balancing..) Visualisation Tool FEC WAP WML / WAP Lookup Server BEC 1st PC WML / HTTP Apache (Web Server) A WAP traffic generator => multiple simultaneous calls BEC registered to the Lookup Server BEC WML Files 2nd PC Access Server 12