The IESG has approved the following document: - 'Network Service Header (NSH)' (draft-ietf-sfc-nsh-28.txt) as Proposed Standard This document is the product of the Service Function Chaining Working Group. The IESG contact persons are Alvaro Retana, Alia Atlas and Deborah Brungard. A URL of this Internet Draft is: https://datatracker.ietf.org/doc/draft-ietf-sfc-nsh/ Technical Summary This document describes a Network Service Header (NSH) inserted onto packets or frames to realize service function paths. NSH also provides a mechanism for metadata exchange along the instantiated service path. NSH is the SFC encapsulation required to support the Service Function Chaining (SFC) Architecture (defined in RFC7665). Working Group Summary The working group has had many discussions on this document. Many individuals from many companies have helped bring together this solution. Over the last 9 months significant effort has gone into fixing issues raised by earlier reviews. While there is still some disagreement (such as on the fact that the WG selected TTL mechanism is a compromise with some accepted imperfections), all technical limitations are identified in the document and dealt with in fashions acceptable to the rough consensus of the working group. Document Quality There are multiple implementations of this work, some from open source and some proprietary. Personnel Document Shepherd: Joel Halpern Responsible AD: Alia Atlas