The call failure rate (CFR) is the percentage of calls to an ISP or any network provider that fail to get through. The CFR is commonly used as a statistical measure in assessing Internet service providers. Companies can also measure the CFR for their own employees who dial in for access to the company's network. Rating companies report on the CFRs for major ISPs like AOL, Ameritech and Mindspring. Visual Networks, formerly Inverse Network Technology, is one the best known benchmarking company of ISPs.