We're in an office environment of about 50 people. A few departments send emails with large attachments extensively and doing so clogs up the WAN connection (10Mbps).
I'm upgrading the networking equipment so that it now uses Cisco 1921/K9 router along with a Cisco SG300 managed switch and a few Cisco SF200E switches (no extra modules/bundles were purchased for these equipments).
I've set up VLANs that will group certain departments together and set up bandwidth limits for each, but if one person decides to send out a huge email it will still affect other people. How do I throttle one specific node--preferably automatically--with my current equipment?