Hardware is a physical component of computer systems such as machines or wiring. For Internet infrastructure, they are grouped into three categories: network devices (such as switches, routers, firewalls, and gateways), servers, and end-user devices (such as personal computers or mobile devices). c. Network Interconnection As the Internet is a network of different networks, the assets providing interconnection are very valuable. Two examples that facilitate interconnection are Internet Service Providers (ISPs) and IXPs. An ISP provides customers with Internet access using different data transmission technologies. An IXP is the physical location where different IP networks meet to exchange local traffic with each other via a switch. d. Communication Infrastructure Communication infrastructure are the basic physical structures and facilities (e.g., buildings and cables) needed for the operation of the Internet. In order to build the Internet, supporting infrastructure is crucial. Infrastructure can be grouped as cabling and linking (wireless, such as microwave, radio, and satellite, and wired such as fiber, copper, broadband), buildings (special purpose facilities like landing points for undersea cables or multi-purpose data centres that are used to house all kinds of hardware and infrastructure), power supply, cooling systems, and physical security (fences, walls, doors, etc.). e. Information Information is derived from the collection of data. Systems (e.g., software, hardware, services) and humans depend on information to make reasonable decisions. In the context of Internet infrastructure, information assets are grouped into four areas, comprising: inventory (of hardware, software, infrastructure, information), network topology, system configuration, and operational information. f. Human Resources Human resources are personnel considered to be an asset to Internet infrastructure. They include administrators, operators, support team, developers, managers, auditors, and end users. No matter how much technical security a stakeholder may have, untrained and ineffective human resources are potential vulnerabilities for their systems. Alternatively, well-trained and effective human resources enhance the security of systems. Important features of human resources include: competence, understanding and support from management, staff’s discipline to follow procedures, and trustworthiness of staff members. 12 Internet Infrastructure Security Guidelines for Africa internetsociety.org