High-availability is enabled by automatically detecting the failure of a WAN link or site and redirecting traffic to working links – to provide users with continuous service. WAN link controllers can also be configured in a high-availability mode with one WAN link controller acting as the primary, and a second WAN link controller as a hot standby.
By bundling (aggregating) multiple, diverse Internet links from one or more ISPs, a WAN link controller reduces the need to purchase multiple and expensive high-speed links. This enables you to increase bandwidth by using cost-effective links without compromising up-time. In addition to managing scalability and redundancy, you can cost-effectively utilize all available WAN bandwidth through intelligent link load balancing. WAN link controllers provide controls for how bandwidth is used to support applications and connectivity. This allows you to take advantage of the most cost-effective ISP rates, while ensuring appropriate levels of bandwidth are available for specific applications.
The performance of applications over the WAN directly affects response time. This includes not just total average transaction time, but assures that users located at performance-challenged sites (such as overseas branch offices) receive an acceptable level of performance. Performance is an important criterion for all networking equipment, but it is critical for a device such as a WAN link controller, as datacenters are central points of aggregation. As such, the WAN link controller needs to support high volumes of traffic delivered between sites. A simple definition of performance is how many bits-per-second the device can support. While this is extremely important, in the case of WAN link controllers, other key measures of performance such as how many WAN links can be supported simultaneously.
Network access and secure delivery of applications over the WAN is vital. Network security addresses key elements specific to applications going over the network, such as required levels of encryption, authentication, and maximum reasonable usage. Encrypted traffic tunnels behave differently on the network than clear text.
Scaling of applications delivered over the WAN is a critical consideration. It is important to understand how many users can use available network resources without having to spend large amounts of money to upgrade the network. It also affects how the network performs when a new version of software is deployed, etc. Performance requirements for accessing datacenter applications and data resources are usually characterized in terms of both the aggregate throughput of the WAN link controller, and the number of simultaneous sessions that can be supported.
WAN link controllers should have an easy-to-use and initiative web interface for managing themselves and the WAN infrastructure they affect.