QoS is the ability to prioritize network traffic to ensure that adequate bandwidth is always available to specific applications, especially during periods of congestion. PowerLink and ShieldLink QoS rules determine bandwidth minimums and maximums for specific types of traffic, and uses load balancing and automatic failover to direct this traffic to links with sufficient bandwidth. For example, based upon user-defined QoS policies, PowerLink controls the link bandwidth allocations to support applications that are prioritized, and which ISP links they are to be sent over. IT personnel can setup QoS rules to determine bandwidth limits for specific applications based on protocol type, source port, destination port, and source IPs -- or any combination of these. PowerLink provides QoS support for all outbound traffic.

Network administrators can define traffic and application limits, and enable application queuing to prioritize different traffic types. This allows you to control available bandwidth so that high priority applications such as VoIP get the bandwidth they require for optimal delivery over the WAN.

In the first example below, an Internet-based business has two ISP connections using BGP for high-availability. Their primary applications are VoIP and email. The applications run smoothly when the principal ISP connection is available. However, when that connection fails, and the backup ISP connection becomes active, their VoIP application utilizes all of the available bandwidth, depriving the email application of bandwidth. This causes a business disruption, as a significant amount of their business is conducted via email, which dramatically impacts productivity and business communications.

In the second example below, PowerLink uses QoS to re-prioritize the VoIP and email applications when the back-up ISP connection is restored. By dedicating bandwidth for each application, PowerLink ensures that the applications will not compete for the same bandwidth, enabling each to get the bandwidth they need for optimal service delivery.

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