A Record

A record that translates a domain name to an IP address. In a phone analogy, this is the equivalent of looking up someone’s name in a phonebook and getting the phone number back.


Anycast is a way of setting up a network in such a way that it allows you to send a packet to a single address and it will automatically be routed to the nearest node in a network. A youtube video explaining anycast more in depth can be found here.


Content Delivery Network

Content Delivery Network: a network of geographically dispersed servers. Each node (also known as an edge server) caches content for end-users to download, and as these nodes are closer to the end-user than the Origin tends to be, latency and download time are reduced.


Canonical NAME

A record that acts as an alias. In a phone analogy, this is the equivalent of giving someone a nickname and when you look up the nickname you get the phone number back.


Also known as outage duration. Downtime refers to a period of time that a system fails to provide or perform its primary function. Unlike uptime, which is often expressed in a percentage, we express downtime in units of time.

Edge Servers

Edge servers are the servers at the ‘edge’ of a CDN network, and are a provider’s closet asset to the end user – these are the servers in a PoP. The edge server caches and or mirrors content that is otherwise stored on the Origin server.


The name of a computer, server or another networked device like a router or switch. In a phone analogy comparable with a person’s or organisation’s name.

HTTP date

The standard,or prefered format for communicating timestamps. The standard is defined in RFC 7231.


Sun, 06 Nov 1994 08:49:37 GMT


The next major version of the HTTP protocol. It is not a full rewrite but rather an evolutionary improvement from HTTP/1.1. The protocol is largely based on SPDY but additional improvements were also incorporated in the RFC draft process.

IP Address

The network address of a computer, server or another networked device like a router or switch. In a phone analogy somewhat comparable with a phone number.


Internet Service Provider

The company that provides Internet services to consumers and businesses.


We distinguish between full-blown outages where the service is completely unavailable, and micro-outages that are of a different nature. Micro-outages generally last a short amount of time, are confined to a specific region or ISP and often go unnoticed by regular monitoring setups. The impact of a micro-outage can range from performance degradation to partial unavailability, or even complete unavailability of a website and its content.


Multiple CDNs

The combined networks of existing CDN providers into one larger network.


Origin refers to the web server where the ‘original’ content is stored, as opposed to cache servers or edge servers. Though the end-user won’t notice a difference between the original content and its copies, we often use the term Origin to refer to the server that is updated and maintained by the content supplier.

Origin Shield

A protective layer in front of the original location of content. This is often part of the existing infrastructure of a CDN provider The difference is that other PoPs will request content from the origin shield instead of the origin thus relieving the pressure on the origin.

Performance Degradation

A condition in which services are not available or are performing sub-optimally. We speak of this status when performance measurements fall outside predetermined limits, resulting in a lower quality of service.


Point of Presence

A location where servers are hosted


Request For Change

A form of change requests commonly used to develop protocols used in IT. Most protocols used in the internet are governt by the Internet Engineering Task Force or IETF.


Round Time Trip

The time it takes a packet to travel to a specific destination and for for an acknowledgement of receipt of the package to travel back to the sender.


Real User Measurements/Monitoring

Monitoring a property’s performance and availability by placing a Javascript tag on a website which will be loaded during page load. The Javascript code will then perform measurements and send the results back to a server for analysis.


Service Level Agreement

The contract between the service provider and the client that documents what services will be delivered, and their quality.


An improved version of the HTTP/1.1 protocol primarily developed by Google whith the main goals to decrease website loading times and improve security. Google opensourced the protocol and formed the basis for HTTP2 .


Secure Socket Layer

The secure connection between Internet browsers and websites, over which private data can be safely transmitted. Websites secured with SSL can be identified in the browser by the padlock icon next to the URL.


The amount of bandwidth that is available for the data to travel.


The amount of time, often expressed as a percentage, that a system was available for its intended purpose. Uptime is calculated by dividing the amount of time the system has been “up” by the total amount of time in the timeframe. Uptime is mostly expressed in either a Montly Uptime Percentage for use in a SLA or on a yearly basis. The other “form” of uptime is the total amount of uptime of a system which is calculated from the moment the system last started until the present time.