Microsoft provides tools as part of the Xbox 360 development environment that let engineers experiment with network performance in multiplayer games. The one we use most often is a network emulator called N.E.W. - see this Wikipedia entry for a high level overview of Network Emulation
There are several open source tools that perform a similar function. One of the easier ones to get set up is Dummynet :
Network emulation essentially requires a PC with two Ethernet cards to act as a gateway: One card connects to the outside world and the other connects to rest of your network via a switch. [Under Windows, this is equivalent to Internet Connection Sharing ]
Dummynet runs on the PC and controls the flow of packets to/from network devices. You need to have some knowledge of how to control a command-line application to get anything useful out of the tool.
The things we control for the testing of SSFII HD Remix include:
- Bandwidth : We need to meet requirements that all applications run under 64 kbps bandwidth restriction - this is roughly the low-end limit of a DSL/Cable connection.
- Latency : We can simulate poor latency connections by inserting a delay in the Internet uplink. The general worst case latency situation we are looking at is 250+ms roundtrip sustained.
- Packet Loss : Games generally need to be able to withstand a 10% random packet loss.
There is a very good article on the use of Dummynet on the personal website of Márton Anka, codefromthe70s.org
Using Márton's step-by-step instructions, you can set up a Dummynet environment on a single PC using VMWare to simulate several virtual PC's.
- Gary

Without revealing too much information, it should be known that Sony and Microsoft have different requirements for their online services.
g->lake++Sony does not place restrictions on bandwidth usage, so considerations are being made to lift the artificial constraints on the game that limit it to 64kbps for PS3.
Our goal is to make SFII the best online experience regardless of platform.
01:46 PM CST