PingPlotter - PingPlotter is a troubleshooting tool that helps IT professionals and neophytes identify, diagnose, and resolve network issues.
NetCut - NetCut is a Software that helps you admin your network by purely on ARP protocol.
SmokePing - Smokeping is a tool for measuring latency.
XArp - XArp – Advanced ARP Spoofing Detection XArp performs advanced ARP spoofing detection mechanisms – made to secure your network.
WinMTR - Free Network Diagnostic Tool. WinMTR is an equivalent of mtr for Windows.
Paessler PRTG - An advanced network monitoring solution to monitor network up/downtime, traffic and usage.