Network Simulator tool allows you to perform network bandwidth and delay simulation (simulate slow/congested links between nodes) on any connection from your computer to any remote node (on the local LAN or remote over Internet).
The Network Simulator utility has driver component and user interface component. The driver component is installed to see all the network traffic passing between Network Interface Card (NIC) and TCP/IP stack.
The user interface component is used to perform creation of the flow and real time monitoring of stats for the created flow(s). Flows are only applied in the driver component when user interface component is running, when user interface component is closed all the flows are removed from the traffic.
The most useful feature of this utility is that you can install it on your workstation on which you are performing development or testing and create delay simulation profile such that delay would only apply to connections according to your filter criteria (source and destination IP addresses, source and destination ports and protocols).