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Kimberly Lacerte
Posted by
Kimberly Lacerte on
March 6, 2017

Ecommerce and Internet Reliability

When traffic on the Internet is slow or interrupted your online business suffers. Customers can’t reach you or they lose interest when your web page doesn’t load in their 8-second attention span, and you lose money. As the IT leader for your business, you need to ensure that your online business is available for customers 24x7. NS1’s Managed DNS with Filter ChainTM technology can help.

Redundancy creates Reliability

It is critical to your business that you avoid a single point of failure that could cause your entire web presence to come crashing down. In addition to disaster recovery, your web presence needs redundant systems to proactively avoid issues that can occur during the day to day running of the Internet. Whether a fiber cable is cut or a local ISP has a power outage; by setting up redundant systems, your web presence remains reliably available even in the face of these routine events.

If you have a content delivery network (CDN), duplicating the content with multiple vendors allows redundancy in your content. If one vendor goes off-line, the second vendor picks up the workload that the other vendor would normally handle.

Multiple DNS vendors give you the same redundancy for your DNS resolution. If your users aren’t being routed to your content, it’s like it was never there. A second DNS provider, acting alongside your primary provider, ensures your users can get to your content regardless of prevailing Internet conditions.

To ensure the highest level of precision over application delivery, NS1 offers a powerful feature called Filter Chain technology, which gives you the ability to augment traditional routing algorithms (eg. BGP) with rich metadata from any source. This means that traffic is steered to the appropriate endpoint based on information that is specifically relevant to you, your users, and most importantly, your customers.

How do Filter Chains work?

NS1's Filter Chain allows for precision control over DNS responses. At a high level, each instance of Filter Chain is like a small application that runs at the edge of NS1's anycast DNS network, shaping the DNS response in a way that is appropriate based on a number of parameters that are specified during setup. A Filter Chain can be as simple as using metadata from NS1's monitoring, or a 3rd party integration, to filter out responses from endpoints that are reporting as DOWN in that moment using the UP filter. There are also filter options that allow for geographic fencing or geographic targeting, routing based on lowest overall latency, and metrics-based filters as well, which can route traffic away from really busy servers and onto servers that are not being fully utilized. All this exists to provide the best possible experience for your users and customers.

Augmenting resilient architecture with Filter Chain


Starting at #1, this is your run of the mill DNS query. Prompt #2 assumes that the recursive that is local to the client has expired information, and this is a fresh DNS query. As the NS1 edge server answers the query, information about the endpoint is taken into consideration.

A.  Are there any answers assigned to this host that are down? If yes, eliminate them from contention and proceed to B. If no, proceed to B.

B.  What kind of load are the available answers under? This Filter Chain has metadata being imported from a 3rd party Application Performance Monitoring (APM) system to define the server load that each eligible answer is under. Answers that are outside the scope of the high or low watermarks are removed from consideration.

C.  In order to have an RFC compliant answer in the case of records that can only exist alone (eg. CNAME), the last filter that is used in this setup is SELECT_FIRST_N where N = 1.

The optimal answer is returned to the client, who now knows the best possible answer based on the criteria set forth in the Filter Chain. This means that in a handful of milliseconds, the client has made a request, NS1’s Filter Chain arbitrated the best answer, and the answer was returned. Given the dynamic nature of this specific setup, as conditions change with regard to whether or not a given endpoint is up and whether a server is over-extended, the optimal DNS answer is subject to change.

For the health of your business, reliable online access for your customers is essential.

Contact NS1 to see what Filter Chain technology can do for your company.