Title says it all. For a bit more info though:
Basically, I have Time Warner cable internet. My speeds maintain a stable 2Mbit/s upload and 20Mbit/s download with average ping times around 30ms.
This crazy thing happens though when I upload anything. I went to upload a 200M file to my server today through sftp and my internet completely choked up. I speed tested it during this upload and my ping time was around 800ms, download speeds of 0.2Mbit/s and Upload speeds of 0.3Mbit/s. Note, I wasn't downloading anything during this time either. It is just straight upload.
What is it that causes this phenomenon? My router is OpenBSD. Is there anything I could set up to fix this problem(by queues or some such), or is this a problem with cable internet?