Cyber-What!? 

Cyber-What!? is simple and powerful voice conferencing client/cerver solution for Windows. Supports up to 60 simultaneous speakers on your LAN or via Internet. 1.4kbps up to 350kbps transfer rates for maximum flexibility and resource utililization.
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Orion Network Performance Monitor 

Orion provides real-time, web based interactive network maps to manage availability, bandwidth & CPU utilization. Orion also has SLA mgmt. reporting and is very customizable. Download a free Evaluation or view live demo at www.SolarWinds.Net/Orion
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Engineers Edition 

An awesome collection of over 38 Networking Tools. From graphing Bandwidth Monitors to Network Discovery tools to Cisco Router tools to a Network Monitor with email alerts, to a Full MIB Browser. As you can see from its size, this toolset is LOADED.
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Network Spy 

An Ethernet packet capture program. It decodes and analyzes IP packets on your LAN. It also lets you measure network load, resolve IP conflicts and build an ARP table. A powerful rules-based filtering engine enables you to perform intrusion detection
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