Network issues caused by Macbook Pro

Hello,

Recently I started having some issues with my network. My MacBook Pro is directly connected to my modem with an ethernet cable. I'm running the latest version of Mountain Lion. It's a 15" MBP mid-2010 model. I have problems reaching websites, though sometimes it goes through. I called my ISP and they said that my throughput up is maxed out by a device on my end. Since my MacBook Pro is the only device connected to my modem, I've finally narrowed the problem down to my MacBook Pro. The only applications that appears to be running is Finder. I closed out Dropbox, Google Music, LogMeIn, Spotify, etc. figuring they may be using data in the background. Are there any applications or system services that may be causing issues? Do you think my network card is going? Any utilities or programs I could use to monitor which applications are using up network resources? When my Mac is taken off the network (shut down), my network appears to be running just fine.


TL;DR: Mac is hogging network, can't figure out why. Help?

Well I think I've fixed the problem!

For those who have the same problems in the future, hopefully you'll find this helpful.

Open the Network section of Activity monitor up to see the incoming and outgoing data from your Mac.

I used a problem called Little Snitch to see which programs were using more data than others. You can also deny/ allow access to programs trying to send or receive data.

It appears that Photostream was uploading all of my images from my trip I went on recently and was hogging all of the bandwidth causing major issues across my network. I decided to disable Photostream on my Mac altogether to avoid issues in the future.

Hopefully this helps others!