The IESG has approved the following document: - 'ConEx Concepts and Use Cases' (draft-ietf-conex-concepts-uses-05.txt) as Informational RFC This document is the product of the Congestion Exposure Working Group. The IESG contact persons are Wesley Eddy and Martin Stiemerling. A URL of this Internet Draft is: http://datatracker.ietf.org/doc/draft-ietf-conex-concepts-uses/ Technical Summary The ConEx Concepts and Use Cases document provides the entry point to the set of documentation about the Congestion Exposure (ConEx) protocol. The document explains the motivation for including a ConEx marking at the IP layer, which is to expose the path congestion information to the network nodes. It particularly focuses on how the ConEx marking can serve as the basis for more efficient and effective traffic management than what exists on the Internet today. Working Group Summary The document is a result of a many hours/emails of discussion spanned over 20 months. Two points that stand out in the WG process are: 1. In the beginning, the document was a mix of a several closely related use cases for ConEx. After much discussion, the document zeroed in on the central use case of ConEx which is informing traffic management, while also providing a discussion of other benefits of ConEx in a separate section. Even though this process took some time, it ultimately helped shape the clarity and focus of the current document. 2. The working group also had an intense discussion on whether the role of statistical multiplexing over longer timescales should be a separate use case. It was ultimately folded in with one of the existing use cases. Document Quality The ConEx Concepts and Use Cases document serves as an introduction and motivation for the upcoming documents that describe more precisely the ConEx mechanisms, IPv6 packet formats and TCP modifications. As such, this is not a specification itself, and no implementations will be created from it, however it will be helpful in explaining how CONEX works to implementers and in guiding experiments. Personnel Nandita Dukkipati is the document shepherd. Wesley Eddy is the Responsible Area Director.