Over the years, network managers have realized the value of frame relay services as a lower cost alternative to leased lines. Frame Relay services offer network-access data rates from 56kbps to 45 Mbps. Frame Relay performance management was designed to provide statistics relevant to the Service Level Agreement (SLA) between a frame relay provider and subscriber. For instance, frame relay probes monitor whether or not CIRs are being exceeded or underutilized. The probes also track round-trip delay, congestion and peak utilization times, accelerating problem resolution in frame relay networks.