The technological world moves fast. It can be easy to overlook certain pieces of kit, software or process advancements simply because they come along with increasing frequency. The word “Anycast” has been bandied around relatively regularly of late, but what exactly is it, how does it compare against similar methods, and what are its associated benefits?
In the simplest of terms, Anycast is regarded as a “Network Addressing and Routing” technique. Its core function is to ensure that any direct traffic request can subsequently be funnelled off to an array of ”Nodes”, based on necessity, network capacity or potential benefit to the user.
With specific reference to a content distribution network (CDN) – a network of servers, which can be localized or in a variety of locations globally, designed with the goal of giving users enhanced internet surfing capabilities – this generally means that any traffic will be pushed in the direction of a local data center (as long as it has the requisite capacity) so that any and all necessary actions can be taken, and processes can be completed seamlessly.
Via a process known as “Selective Routing”, Anycast is fully capable of carrying out and completing requests regardless of the amount of traffic, or in the face of a DDoS attack.
Those that are more au fait with Anycast will be fully aware that it is frequently uttered in the same breath as “Unicast”. But why is this the case, what are the similarities, and what are the differences?
It is worth noting for the outset that the vast majority of all online activity currently operates via Unicast, which enables “One-to-One Transmissions” from one location to another. However, while Unicast is well established, it does have an inherent flaw; under certain conditions, it can be very vulnerable to DDoS attacks.
This is due to the fact that traffic, when in high volumes, can be directed to a particular node, which can result in it being overwhelmed – especially if a large amount of that traffic has been directed specifically with an attack in mind – making the network far more vulnerable, and potentially even resulting in network confusion, meaning that genuine requests could be rejected.
Anycast, however, has be created with this fallibility firmly in mind. Because of this Unicast flaw, Anycast has been designed to be robust; if it is ever likely that excess traffic is likely to overwhelm a network, traffic will instead simply be rerouted to one or more capable data centers.
Anycast is designed very specifically to ensure that a specific data center does not become weakened – potentially to the point of outright collapse – as a direct result of a DDoS attack. Rather than all traffic ending up reaching a solitary data center, Anycast works to divert traffic, meaning that numerous data centers will soak up the attack, to the extent where an attack is eventually nullified completely.
It is, however, important to understand that an Anycast network is by no means simple to set up. It needs to be crafted and subsequently implemented professionally to ensure it can be as accurate and valuable as possible. This will necessitate working with an expert supplier and garnering as much knowledge as possible about what needs to be done to repel attacks and keep networks - and users - as secure as possible.