A company that maintains caching servers that speed the transfer of information across the Internet's infrastructure and offers managed access to these servers for a fee.
Many companies think that if they host their Web site at an Internet service provider (ISP) or at a major Web hosting company, the site will always be accessible from anywhere on the Internet, but this is not necessarily true.
Traffic congestion can cause access to a Web server to be slow and unreliable from various parts of the Internet at various times of the day, and equipment failures (such as routes going down at Internet peering points) can make a server completely inaccessible to certain portions of the Internet until the problem is fixed. («Peering» means two ISPs or other providers passing traffic between each other's customers.)
One solution is to mirror (replicate) your Web server at various points around the globe so that a copy of your site is relatively close to any location on the Internet. For companies with a global presence, this is a fairly simple solution to implement, but most companies do not have the presence or the resources to implement global mirroring.
A better solution might be to use the services of a caching service provider (CSP), which maintains cached copies of your Web site at various points in the Internet's infrastructure and provides tools for managing and load balancing the content to handle traffic spikes that occur at certain times of the day or year.
CSPs maintain data centers around the world with caching server farms that have high-speed connections to the Internet's backbone.
These caching servers are usually designed to cache Web content and often support features such as content management and proxying. Caching servers can also be used within the corporate network to speed access to large, distributed corporate intranets.
CSP is an acronym that stands for Caching Service Provider.