Open your Web browser and navigate to the CNET bandwidth meter. Enter your area code, connection type and Internet service provider in the box in the upper-left corner. Click the "GO" button to start the test. View the connection speed in the graph provided. Compare your results to Comcast's advertised speed.How do I test my wireless speed?
Click "Begin Test" to ping the nearest server and test your download and upload rates. These tests work by transmitting a signal from your network to the server and measuring the response's latency, similar to the way a radio ping test measures the latency of a signal's bounce off a landmark or building.