There has been a lot of buzz about the recent fall update for the Xbox 360; however, an important new feature which has not been mentioned is support for the Link Layer Topology Discovery (LLTD) protocol. In its basic form, LLTD allows a Windows Vista PC to accurately map the topology of your home network. In short, this map is a rich diagnostic tool designed to be a visual replacement for command-line ping (and I suppose arp). LLTD Mapper (component which initiates probes and draws the map) heuristics are able to ascertain what types of network elements (which may or may not implement the LLTD Responder) are interconnecting PC/devices that implement the LLTD Responder (component which responds to probe requests). If a PC/device implements the Responder, rich information such as: custom icon, IPv4/IPv6 address, MAC address, configuration URL, etc. is visible within the map. Below is a map of my home network, which now shows the Xbox 360!
The LLTD Responder component will be available for Windows XP some time in the near future so XP machines will also show up in the Vista map. There is a great deal of improvement that can go into the network map; and folks within networking are actively planning for these improvements. So what about QoS you ask? As Mathias previously mentioned, qWAVE APIs require that the destination host support LLTD to do real-time bandwidth estimation, etc. So, in addition to enabling a visual map of your home network, LLTD enables a device to support adaptive AV streaming via qWAVE support. Media Center on Vista is a great example of a qWAVE enabled application that does real-time adaptive streaming to the Xbox 360 (and other Pika devices) that support LLTD.
What would you like to see the network map support?
— Gabe Frost