The web browsers by default limits number of concurrent connections for each host. When that limit exceeds, the resources (like CSS, images, etc.) will remain in queue waiting to be downloaded until the prior downloads are completed. This results slow page load times user experience. One solution to reduce page load time is by domain sharding. This technique splits the resources download across multiple sub-domains (eg. static1.webfoobar.com, static2.webfoobar.com) resulting an increase in simultaneous connections.