A basic feature of application delivery controllers (ADCs, also known as load balancers) is response affinity. Once the ADC establishes a connection between the user and the application it keeps the user connected to the same server for the duration of their interaction with the application. Without this feature, users would find their application connection starting all over for no apparent reason, reducing the application’s perceived performance.
Similar affinity capabilities can be very helpful in DNS as well. Here is why. The application may be designed to allow extended idle time, but timeouts at the network layer can result in the user needing to refresh and reconnect. This is fine – unless the DNS cache on their device expired and they need a DNS lookup to get back to the site.
Online advertising revenue depends on both fast responses to online bid requests and the ability to deliver appropriate ad content to the user’s browser. DNS traffic routing needs to send the request to a server where the appropriate ad data, defined by user data tied to a cookie for example, is already cached. If your content is distributed across CDNs, Cloud instances, or data centers, the DNS lookup can extend to the displayed ad content causing a re-bid for the space. Result: Ad revenue lost.
One of the cool features in NS1’s Managed DNS is the Sticky filter algorithm. Using a hashing algorithm, NS1’s Sticky filters ensure users of a specific DNS resolver, or resolvers in a specific network, are consistently routed to the same answer. For applications with high performance requirements, such as ad-tech, this optimization of cache locality means increased ad revenue. Problem solved.
This server affinity is simple in concept but not available on traditional DNS services. The ability to incorporate advanced algorithms, such as stickiness, into DNS traffic management is what sets NS1 apart from the competition.
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