Verizon announced at Spring 2006 VON Wednesday that it is providing service-level agreements on the quality of its VoIP services.

These guarantees use standard mean opinion score (MOS) ratings of how good the voice sounds over a phone connection and offers a credit if the service falls below the objective stated in the SLA.

Verizon is offering the SLAs on its managed IP PBX service and offers two levels depending on which coder-decoder is used. For G.711 codecs, the company will guarantee a 4.0 MOS score on average over the course of a month. For a G.729 codec it guarantees a MOS of 3.8.

Depending on how far below the SLA mark the average performance falls, Verizon will credit customers with up to 100% of the monthly service management fee.

The quality is tested using a Cisco router installed on the customer premise for the sole purpose of probing voice paths on the network. The data it generates is analyzed by Concord management software within Verizon's network to determine the MOS performance.

Verizon is also offering a guarantee on time to repair outages. The company promises to fix any problem within three-and-a-half hours. That is not the mean time to repair, which is an average of how long it takes, but three-and-a-half hours for each problem.

If the company fails to meet the promise, customers get credits for the monthly management fee for the service.