Software by Nessoft, LLC:

PingPlotter Pro is a network monitoring and troubleshooting tool. It runs in the background collecting data, and then allows network professionals fast and easy access to network routing and performance information. Remote tracing, a native web interface and highly configurable alerts are just some of Pro's features. Additional VoIP targeted capabilities such as Jitter, MOS, packet loss and latency make it a must have tool in any admins toolbox.

MultiPing is an application built for monitoring graphically one or more TCP/IP hosts, while providing detailed historical information about the collection period. Using the proven and powerful PingPlotter engine technology, MultiPing allows you to monitor numerous targets simultaneously giving you the data you need to choose between multiple possible hosts, to monitor uptime and performance or just keep track of general connectivity.

PingPlotter Standard is a lightweight network monitoring and troubleshooting tool. It can run in the background collecting data while you continue to run applications, and then allow you to quickly look at the data in an intuitive graphical format when you experience problems (reduced call quality for VoIP, slowdowns or disconnects with applications, etc.). PingPlotter Standard is great at allowing you to collect data over time to see trends.