Content delivery networks (CDNs) are a type of distributed computing infrastructure, where devices (servers or appliances) reside in multiple points of presence on multihop packet-routing networks, such as the Internet, or on private WANs. A CDN can be used to distribute rich media downloads or streams, deliver software packages and updates, and provide services such as global load balancing, Secure Sockets Layer acceleration and dynamic application acceleration via WAN optimization techniques.