3.5.1 Server Side Monitoring 

Server Side monitoring in the context of Web delivered service involves capturing 

information on HTTP requests to and replies from the server, at the server itself. The 

problem with server side monitoring is that is does not provide an accurate representation of 

the end user experience because failed attempts to the server cannot be detected. 

Another issue with server side monitoring is the performance implication of monitoring 

HTTP to this level of detail for each request and since some customers may not require such 

detailed monitoring it could be an unnecessary overhead. 

3.5.2 Monitoring via a Proxy on the Client Side 

The other alternative to server side monitoring is monitoring between the server and the 

browser by forcing HTTP requests to the server through a proxy. Ideally the location of the 

proxy should be on the client, the reasons for locating the proxy on the client have been 

discussed already. The implications of monitoring by a proxy include: 

Not all services that are accessed via the proxy may require monitoring. The 

proxy must have the ability to configure, reconfigure and disable monitoring of a 

service. 

It results in another layer of indirection and there may be performance 

implications in monitoring performance 

Service performance information needs to be passed back to the service provider 

and perhaps a third party. The proxy needs to know what information to send and 

at when to send it. 

Ideally the proxy should have the ability to detect service errors and backend 

component failures that impact service availability but return a valid HTTP reply. 

So despite the advantages of using HTTP proxies for service monitoring, there are 

significant obstacles to overcome if they are deployed.