How to monitor internet usage without a manageable switch?

What is port mirroring?
Usually, a computer connected to a switch or a router can only receive its own packets. A switch with port mirroring allows you to monitor network traffic from a mirroring port.
With port mirroring enabled, the switch sends a copy of all network packets seen on one port (or an entire VLAN) to another port, where the packet can be analyzed.
How to monitor network without port mirroring?
There're three methods to monitor your network without port mirroring.
1. Using a broadcasted Hub
A broadcasted hub is a data packet repeater commonly used in broadcast networks.
Most broadcasted hubs provide a uplink port to connect with a up layer device. You shall connect the up layer device to the uplink port of the hub (Note: Do not use the port next to the uplink port).
However, most broadcasted hubs only work in 10Mb speed, and all the computers connected to the hub will share the bandwidth, and it is unstable. So we recommend you use a manageable switch instead.
2. Windows Gateway, Proxy Server or Bridge
Windows Gateway
If a port mirroring switch is unavailable, you can setup a windows gateway in your network edge. By using an internet monitoring/filtering product in this windows gateway,
you will be able to monitor all internet traffic.
How to configure Windows 2008 Server IP Routing?
Proxy Sever
A Proxy Sever is a computer that offers a computer network service to allow clients to make indirect network connections to other network service.
Like the gateway solution, you also can do monitoring/filtering in the proxy server. To make things simple, some proxy servers have monitoring/filtering modules integrated,
while some monitoring/filtering programs also have a proxy module integrated.
For example, you can easily enable the proxy server service in WFilter enterprise. For more details about WFilter proxy settings, please check:
http://www.imfirewall.us/help/doc/deploy_proxy.htm