It is important to distinguish the protocol layer at which multi-segment Rether works from RSVP, which is an emerging Internet standard that is designed to make real-time performance reservations over wide-area networks. The above figure illustrates where Rether fits in the end-to-end bandwidth reservation framework. In the figure, an end-to-end real-time connection is to be established between a sender node and a receiver node across the internet. This connection can be set up using a real-time connection setup protocol such as RSVP, which in turn relies on link-layer reservation mechanisms to actually set up the underlying connection. One of the subnetworks that participates in the real-time connection in the above figure is a switched multi-segment Ethernet while the others are ATM, FDDI, etc. The abstraction that multi-segment Rether exposes to RSVP is thus a real-time capable Ethernet-based subnetwork that can provide the same bandwidth guarantees as ATM. Hence, Rether plays a complementary role to higher level reservation protocols such as RSVP in that it functions exclusively as a link-layer building block for making bandwidth reservation on Ethernet.