Are you one of those geeks that likes checking out the capabilities of your router? Do you run the various Internet Speed Tests available just for fun? If so, head over to the new Microsoft Internet Connectivity Evaluation Tool. You will only be able to run the test on a computer with Windows XP or Windows Vista (it uses an ActiveX Control).
One primary function of most home Internet routers is Network Address Translation (NAT). Routers providing NAT support assign private IP addresses on the local network. NAT maps these private addresses on the inside network to a public IP address on the outside network so that computers behind the Internet router can communicate with the rest of the Internet. Since Network Address Translators can work in different ways, this test uses Microsoft servers to identify your router's NAT type. Some protocols work better through routers that act as cone-type NATs than routers that act as symmetric-type NATs.
Internet routers sometimes lose information that is being transferred across the Internet when they experience congestion (full router queues). This loss of information is known as packet loss. Internet protocols like the Transport Control Protocol (TCP) can use packet loss as a congestion indicator. Explicit Congestion Notification (ECN) is a mechanism that provides routers with an alternate method of communicating network congestion. This notification effectively reduces TCP retransmissions and increases throughput. This test attempts to download a short Web document, first with ECN enabled and then again with ECN disabled. If both downloads succeed, the test passes, which indicates that your Internet router successfully allows packets through with ECN options set.
Window scaling is a Transport Control Protocol (TCP) option introduced for addressing performance problems. Some Internet routers cause TCP data transfers that use window scaling to fail, particularly when there's a mismatch between the scales chosen by two computers transferring the data. This test downloads a series of Web documents of increasing length until either an incomplete download is encountered or all downloads succeed. Success indicates that your router allows Windows Vista to negotiate the best data transfer rate and help improve download speeds.
Many applications need to open ports (allow incoming traffic) through an Internet router, particularly when both communicating endpoints are behind different NATs. Modern routers allow hosts to create such open ports using Universal Plug and Play (UPnP). This test ensures that the router has UPnP enabled, can support a reasonable number of open ports, and can maintain these settings.
This test creates 80 concurrent TCP connections to external Web servers and keeps them alive over the period of two minutes by attempting continuous data download using HTTP. Passing this test indicates that your router robustly supports multiple computers or programs accessing the Internet simultaneously.