A few years back we had a Acterna Testpad FST2802 (datasheet) on loan from a vendor to test a big rollout of fiber we did together. As we only had one unit we couldn't use it to test other things then the rollout where the vendor had the other unit. So I decided to write a little software program to act as a software based reflector.
While troubleshooting a bandwidth issue for a customer today I noticed a lot of TCP traffic between different hosts of the customer on tcp port 7680. As the customer has multiple locations with diverse bandwidths available this started to hog up quite some bandwidth. After some research I found out that tcp port 7680 is used by Windows 10 to distribute windows updates to other domain clients.