Check for no Request to Node.js for some particular time

How can I monitor incoming request in Node.js,

Here , actually I am getting continues heart-bits from MODEM , I want to monitor the different request... For some time if I didnt get any request from particular IP i want to some other function ,

How can I check for NO REQUEST FOR some time to NODE.js ??

I tried with

    req.on('close', function (){}) // but didn't work for me ...:(    

In your request handler, store the IP of the request with the time that the request was received.

Write a function that looks at your store of IPs and determines if there are any IPs from which a request hasn't been received recently enough and does whatever you want to do in response.

Pass that function to setInterval