National Security Telecommunications Advisory Committee, Vulnerabilities Task Force Report: Internet Peering Security (Mar. 27, 2003) (full-text).
During the evolution of the Internet, it became clear that centralized locations were needed to facilitate the exchange of traffic among the various operators' interconnected networks. This led to the development of the first public peering points, hereafter referred to as network access points (NAP), and later to direct or private peering points between network operators.
If a physical attack were the method of choice, only a well-coordinated attack on numerous NAPs and private peering points distributed across the United States could impair overall Internet operations. Such a substantial attack would be very difficult to plan and implement and require a large amount of resources. According to a previous report by the National Security Telecommunications Advisory Committee (NSTAC), the loss of assets in a potential single point of failure would not cause a nationwide disruption of the critical telecommunications infrastructure.
Specifically, the physical destruction of a NAP, or even several NAPs would not impair Internet functionality because of the number and geographic diversity of NAPs and the multiple means of interconnection available to Internet service providers (ISP). Even if a major peering point were lost, peering of ISPs would continue to occur at other private peering points and other NAPs. Moreover, if multiple NAPs were lost, traffic flow across the Internet could be impacted but not completely disrupted because of the multiple routing options.