I wanted to toy around in creating myself a little bandwidth monitor/meter. I found someone wanting to do the same exact thing at the old arduino forums. http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1231644836. But I am having some trouble with how this can be configured (hardware wise) to accomplish my goal though. Ideally I would like to capture all of the data going over a network cable as the guy described in his post. Putting this device between the DSL/Cable modem and the router would obviously get all the data that any of my computers are transferring to and from the internet. The issue is getting this information without causing other issues.
Idea 1: Using some kinda pass through. 1 Wiznet type device connected to the dsl/cable modem then the counting the frames passing over the network and then passing that data along to another wiznet chip sitting on the "other side" connected to the router. The problems I could see with this is that the arduino might not be fast enough and could degrade the network. I personally don't like this as it seems that it would be problematic and overly complicated.
idea 2: Using the device almost like a "tap". My thought was to simply plug a network "hub" into the cable modem and plug the the arduino into another port on the hub and then from the Hub to the router. My thought on this was since a hub passes all data to every port on the hub the arduino board would see exactly what was coming over the wire. When I did this with my linksys hub it didn't appear that the hub was actually passing the data to all ports like I expected. I set this up and used wireshark to monitor the packets with my other network device on my computer. The network card on my PC that I was watching with wireshark that was acting as the arduino was not seeing any of the data that the normal network on my PC was seeing. I had the network card acting as the arduino in promiscuous mode as well. Obviously a big problem if the arduino never saw any data :). So my question is there any type of device that will do what I am expecting the hub to do? I was doing some reading that I could use a "switching PHY chip". I am not even real sure what that would accomplish as I haven't done much research on such chip or even if it what I am wanting. I know port mirroring is a feature on some cisco switches, so I know it is possible. I also would think it would be fairly cheap as well.
Any help or information regarding this would be greatly appreciated.