Understanding Forward Error Correction - Understanding-Forward-Error-Correction/Understanding-Forward-Error-Correction

Forward error correction (FEC) is a technique to mitigate packet loss. FEC works by adding additional packets, called repair packets, to the traffic stream, which enables the receiver to recover lost packets. FEC brings value to links, such as wireless links, which may encounter sporadic packet loss. Cradlepoint recommends enabling FEC for business-critical traffic that is sensitive to packet loss. Packet loss mitigation provides better quality of experience to end users.

In Cradlepoint’s implementation, FEC is enabled on a per-traffic-class basis. The traffic class is referenced by traffic steering rules. Traffic from all sites sent to another site or to an internet destination is protected by FEC when using a traffic steering rule with a configured FEC-enabled traffic class. At present, a constant packet overhead of 20% is added to the traffic.

FEC protection applies only in the link between a site and the NetCloud Exchange Service Gateway. In the case of site-to-site traffic, when the originating site and the destination site have FEC-supported devices and the originating site uses a traffic steering rule with a FEC-enabled traffic class, the destination site receives the FEC protected traffic.

FEC performance is displayed on the SD-WAN section of the Network Status dashboard in the Overhead and Loss Corrected tiles. The dashboard helps administrators determine to enable or disable FEC based on the Loss Corrected percentage data. If the Loss Corrected percentage is high, then FEC is proving useful and should be kept enabled. If not, the administrator can disable FEC and avoid the overhead FEC packets. See Viewing the Network Status Dashboard for more information.Viewing the Network Status Dashboard

Enabling or disabling FEC causes the Secure Connect overlay to restart. A short disruption to traffic may be seen at that time.

With a valid SD-WAN license, the following Cradlepoint endpoints, with minimum NetCloud OS version 7.23.60, and using traffic steering rules configured with a FEC-enabled traffic class are supported:

See Customizing Traffic Classes, for details on enabling FEC for a traffic steering class.Customizing Traffic Classes