How Edge DNS GSLB Ensures App Availability During WAN Failure

Detecting IP path failures on enterprise networks is becoming increasingly complex with SD-WAN and multi-cloud approaches. Regardless of the way networking and hosting is being performed by the IT guys, users need to always be able to use their applications, so it’s absolutely vital to circumvent WAN failure scenarios. Edge DNS GSLB (Global Server Load Balancing) is a great solution for this. DNS already plays a crucial part in the user to application binding process. Adding GSLB functionality to DNS servers at the network edge brings capability for service availability detection and intelligent application routing decisions.

From the user perspective, detecting IP network failure is fairly easy. From the application viewpoint, it’s a bit more complex. And at any other location on the network it is nearly impossible to check if a user can access his application. That explains why users often inform IT services of an application failure from their site when in reality the root problem is at the network level. Most of the time checking user to application access requires solutions like APM (application performance management) which, while bringing lots of monitoring information, are complex and costly to put in place.

For Failure Detection, Load Balancers and Traditional GSLB Solutions are Limited

Centralized analysis – for example embedded in the load balancer or in a traditional GSLB solution – is not good enough for detecting failure at every location on the network. In order to obtain the global picture of the entire client-to-application mesh, the central monitoring process needs to implement complex client and application supervision and try to rebuild the meshing topology. Configuration of geographic dispersion of the client and application resources can help in modelizing the network structure but requires continuous maintenance and adjustments.

Edge DNS GSLB Detects Issues and Takes Action for Intelligent Routing

By being located near the client, the EfficientIP Edge DNS GSLB service can continuously check the availability of the application resources, following the same network path that will be used by the client to reach the server hosting the application. Consequently, the GSLB is able to answer DNS requests from the client with the IP address of a server which is definitely reachable.

In case of a WAN issue – such as a telecom link problem, IP routing trouble, application server unavailability or a data center outage – the GSLB will choose the best destination that fits the client usage for the region in which it is located.

For example, on the multi cloud hosting of the application with the app.my.local FQDN as shown on the following diagram, the Edge DNS GSLB in Atlanta (in blue) can detect an issue in the IP WAN network towards the datacenter located in the US and automatically redirect the traffic for this application towards the UK datacenter.

Guaranteeing Application Availability

For ensuring service continuity, there’s really no need to complexify your network infrastructure with difficult to manage solutions, when DNS is simple to implement and understand. Edge DNS GSLB from EfficientIP brings you heightened detection of IP WAN failure and redirection of application traffic to the available cloud hosting the application. In today’s competitive environments, that guarantee of application availability is a key differentiator for most organizations.

See also

• GSLB & Automated Application Deployment
• DNS GSLB for Disaster Recovery
• Application Traffic Routing with DNS GSLB