Differentiated services enhancements to the Internet protocol are intended to enable scalable service discrimination in the Internet without the need for per-flow state and signaling at every hop. A variety of services may be built from a small, well-defined set of building blocks which are deployed in network nodes. The services may be either end-to-end or intra-domain; they include both those that can satisfy quantitative performance requirements (e.g., peak bandwidth) and those based on relative performance (e.g., class differentiation). Services can be constructed by a combination of
- setting bits in an IP header field at network boundaries (autonomous system boundaries, internal administrative boundaries, or hosts),
- using those bits to determine how packets are forwarded by the nodes inside the network, and
- conditioning the marked packets at network boundaries in accordance with the requirements or rules of each service.