It's Microsoft's Content Delivery Network. http://www.datacenterknowledge.com/archives/2009/06/04/why-microsoft-built-its-own-cdn/


>2) 213.199.148.* - 213.199.149.* - These use http (at least initially), port 80 and resolve to lon9.msecn.net which apparently is Microsoft Edge Content Network. The call is made by svchost.exe. If I leave the firewall warning on the screen without answering Allow or Deny (which I assume keeps it in a sort of suspended state) then I can continue to access the internet as normal. But if I block this then within minutes my internet access to most websites is affected including to google.com, wikipedia.com, even Hotmail.com. Not all sites are affected, most but not all, and I cannot find a pattern between the few I can still get to. I have no idea what MS Edge Content Network is or does or why it should affect my internet connection like this. But if I want access to most sites I need to allow this.