It is also possible to pass parameters using the POST method from a HTML form that can 

then be used by the server to determine the service function the user is wants to access. In 

this case the URL will not indicate that these parameters have been sent to the server as  

POST sends form parameters in the body of the submission [19]. 

2. If a local HTTP proxy is used in the customer premises, the request is passed to the 

proxy to be handled. If this local HTTP proxy has a parent proxy, then it may in turn 

pass the request on to the parent request to be dealt with. 

3. Once the request reaches the highest level proxy, the request is then passed to the Service 

Provider. This may take place over the Internet or perhaps via a leased line directly to the 

Service Providers Premises. 

4. When the request reaches the Service Provider's web server, it may be a request for a 

static document in which case the requested resource can be returned immediately. In the 

case of dynamic data such as retrieving the listing of mails in a user's inbox, the web 

server may query information from a database that is to be returned to the user via the 

web server. 

5. The reply to the request is usually returned to the end user via the path and proxies that 

the request was sent on. The resource may be cached, if appropriate, in any of the proxies 

on the return path to the client. This may allow the resource to be accessed from the 

proxy later by other users in the customer premises without having to retrieve the 

resource again. The reply is the formatted by the user browser to display the information 

requested. 

3.3.2 Where can Availability and Performance Issues Occur 

Even looking at the relatively basic example above, failures or performance impacts may 

result from any of the following: 

Any network component such as the connection between the end user and the local 

proxy, the web server and database or the local proxy and web server 

Any proxies used in the service delivery chain may fail or impact performance 

The web server(s) that the service is provided via may fail or impact performance 

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