Autodesk 15606-011408-9330 User Guide - Page 57

Autodesk MapGuide Viewer Autodesk MapGuide Server A request layers 1 & 3 request layers 2 & 4 request layers 5 & 6 process request Autodesk MapGuide Server B Autodesk MapGuide Server C process request return data process request return data draw layer 1 draw layers 2, 3, 4, 5, & 6 return data parallel process serial process Simultaneous request model MapAgents and Server Ranking When the ISAPI, NSAPI, or CGI MapAgents receive a request from a MapGuide client, they rank the available servers and select one to which they dispatch the request. If the chosen server is offline or invalid, the MapAgent tries the next server in the rank. CGI MapAgent Each Autodesk MapGuide client request invokes a separate instance of the CGI MapAgent that lasts only the duration of the request. Because of this, the CGI MapAgent cannot track the number of requests dispatched to each server. It randomly selects an available server for each request and then ranks all other servers based on their proximity to this server in the list that appears in the Window's registry. The CGI MapAgent distributes requests evenly among all available servers regardless of their current workload. Architecture and Performance | 57