Network availability refers to the operational status of a computer network and its ability to quickly make connections, process traffic, and respond to user requests.
Network availability, also known as network uptime, is a measure of how well a computer network—whether a local area network (LAN) or a wide-area network (WAN)—can respond to the connectivity and performance demands placed on it.
Network availability is a key consideration in disaster planning, but it also has critical impacts on everyday life and work. For organizations, network downtime or sluggishness equates to business downtime, at considerable cost to organizations through inefficiency, lost sales, lack of critical data for decisions, and other harmful effects. For individuals, network availability ensures the ability to communicate with and interact with others, whether that’s through a cellular network text to a friend, an online purchase or streaming entertainment, or a call for emergency services.
Network availability is calculated by dividing the uptime by the total time in any period. The goal is 100% availability, although another commonly referenced goal is known as “five nines,” or 99.999% availability. That’s the equivalent of only a few minutes of downtime in a year. A variety of measures, including WAN acceleration or optimization, may be undertaken to reach these goals.
Network availability is a fundamental prerequisite for access to data and applications. It can be a key concern for enterprises that run multiple data centers, since users need to be able to access application servers and data everywhere with the best connections and fastest performance possible.
How many times have you waited for service from a clerk or provider who struggled because their computer was “slow?” Without a highly available network, users can’t access the data and applications they need—or can’t do so quickly enough. At the extreme, a denial of service can result, leading to frustrated employees, unhappy customers, and lost business and goodwill.
Some of the many factors that can affect network availability include power supply or physical disruption (such as may be caused by natural disasters), component capacity and connection limits, component failures, and malicious attacks. In addition, when a network connects users with data spread across large geographical distances, latency becomes a significant factor in network performance.
There are as many solutions as there are causes of disruption. For instance, because 100% availability is the target, many organizations incorporate redundancy and failover systems into their networks to ensure that if a component goes out of service, a backup takes over. Load balancers help to ensure that requests are distributed to the resources most able to quickly respond and helping to prevent any individual component from being overwhelmed. And the ability to easily and efficiently scale operations up or down to meet spikes in demand—including the capacity and security mitigations to withstand denial-of-service (DoS) attacks such as SYN floods, UDP floods, PUSH and ACK floods, and teardrop attacks—is frequently addressed through cloud services as well as through security solutions specifically designed to protect network availability.
F5 BIG-IP DNS optimizes network availability for users and applications by monitoring the status of network components and routing users to the closest or best-performing physical, virtual, or cloud environment. When configured as a full-proxy device, it intercepts all DNS queries and hyperscales in response to distributed denial-of-service (DDoS) attacks, mitigating the attack and protecting the network infrastructure behind it. Whether deployed as hardware, virtual editions, or a cloud service, BIG-IP DNS provides “always on” availability.