Realtime graph on webpage

I want to display a real time graph showing the network traffic passing through router. By real time I mean updated every second. The graph rendering need to happen on the browser to reduce the load on the router CPU 1. Need to browser side rendered graph (updated every second ) to show the traffic flowing in the network router. 2. need to establish what kind of data is required from the router for displaying the TX and RX (in mbps) . 3. The mechanism should be scalable to add more graphs. Eg the router may have multiple Ethernet ports. Each port has a RX and TX traffic. having 4 ports requires 4 TX and 4RX totally 8 timeseries graph to be plotted on the browser.