Level 3 Communications: A communications and information services company headquartered in Broomfield, Colorado, USA. It has operating locations throughout the US and Europe. The company operates one of the largest communications and Internet backbones in the world. Level 3 is a Tier 1 network and the current owner of AS1, but it operationally uses AS3356, which, as of 2007 consistently has one of the highest ranked connectivity degrees on the Internet.

SAVVIS, Inc.: formerly SAVVIS Communications Corporation) provides technology infrastructure for enterprise applications. SAVVIS delivers "IT infrastructure as a service" by combining virtualization technology, a global network and 24 data centers in the United States, Europe, and Asia, automated management and provisioning systems, and a best practices operations model. SAVVIS has 4,500 business and government customers.

UUNET: is one of the oldest and largest Internet service providers and one of the nine Tier 1 networks. It is based in Northern Virginia. Today, UUNET is an internal brand of Verizon Business (formerly MCI). As of 2005, its Internet service and infrastructure, assigned AS701 maintained the highest outdegree of any ISP.

Verio: is an internet service provider (ISP) and web host in the United States. Incorporated in 1996 in Denver, Colorado, it is currently a wholly owned subsidiary of Nippon Telegraph and Telephone (NTT) Communications, which purchased it in 2000. Verio was formed from a consolidation of dozens of smaller ISPs.