How to configure the number of concurrent downloads in IIS / nginx?

Question

Nginx

Hello!
I decided to test the IIS 7.5 server for the number of concurrent downloads.
Added a site, shared the folder via Http
Set the settings on IIS (site settings, application pool):

• Queue length 20000
  
• Waiting time 120
  
• Maximum number of parallel connections 65535
  
• Maximum bandwidth 4294967295
  

И все равно на выходе по 6 файлов грузит:

Для тестирования написал небольшой скрирт который отправляет AJAX запросы на сервак для загрузки.
Тестировал на разных машинах IIS, Windows 7, Windows Server 2008R2.
Затем решил проверить на nginx под windows, и там то же по 6 загрузок.
P.s дело не в тестировщике т.к. когда начинаешь грузить с других машин, тестер находиться в режиме ожидания, и выделяет максимум 1 поток.
Откуда магическая цифра 6?

Answer 1

The HTTP specification, circa 1999, recommends that browsers and servers limit the number of concurrent requests to the same host to two (Fielding et al. 1999). This specification was written long before the significant expansion of download channels and was designed for connections with low download speeds. Most browsers support this thread limit in the specification, although the move to HTTP 1.0 increases the number of concurrent downloads to 4. Therefore, most browsers are seriously limited by this setting if they have to download a large number of objects from a single host, in IE8 this number is about 6 out of - due to significant costs for establishing a new connection