[MS-OCSPROT]: Skype for Business and Skype for Business Server Protocols Overview This document provides a system overview for the protocols in the Skype for Business Server system. It is intended for use in conjunction with the Microsoft protocol technical specifications, publicly available standard specifications, network programming art, and Microsoft Windows distributed systems concepts. It assumes that the reader is either familiar with the aforementioned material or has immediate access to it. A protocol system document does not require the use of Microsoft programming tools or programming environments in order to implement the protocols in the system. Developers who have access to Microsoft programming tools and environments are free to take advantage of them. Intellectual Property Rights Notice for Open Specifications Documentation . Technical Documentation. 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If you have access to Microsoft programming tools and environments, you are free to take advantage of them. Certain 1 / 73 [MS-OCSPROT] - v20210817 Skype for Business and Skype for Business Server Protocols Overview Copyright © 2021 Microsoft Corporation Release: August 17, 2021 Open Specifications documents are intended for use in conjunction with publicly available standards specifications and network programming art and, as such, assume that the reader either is familiar with the aforementioned material or has immediate access to it. Support. For questions and support, please contact [email protected]. Abstract Skype for Business and Skype for Business Server is a client-server product that is based on the Session Initiation Protocol (SIP) to facilitate real-time communications between users. Protocol clients, such as Office Communicator, are used to sign in to Communications Server. Users can initiate calls to one or more users who are also signed in to Communications Server by using different protocol clients such as IM, audio, video, VoIP, and applications-sharing. These clients are enabled via other protocols. Communications Server aggregates the user’s presence from all of the user’s protocol clients and publishes that presence information for other users authorized to view it. This document describes the intended functionality of the system and how the protocols in this system interact. It provides examples of some of the common user scenarios. It does not restate the processing rules and other details that are specific for each protocol. These details are described in the protocol specifications for each of the protocols and data structures that make up this system. 2 / 73 [MS-OCSPROT] - v20210817 Skype for Business and Skype for Business Server Protocols Overview Copyright © 2021 Microsoft Corporation Release: August 17, 2021 Revision Summary Revision Revision Date History Class Comments 4/4/2008 0.1 Major Initial Availability 4/25/2008 0.2 Major Revised and edited the technical content 6/27/2008 1.0 Major Revised and edited the technical content 8/15/2008 1.01 Major Revised and edited the technical content 12/12/2008 2.0 Major Revised and edited the technical content 2/13/2009 2.01 Major Revised and edited the technical content 3/18/2009 2.02 Editorial Revised and edited the technical content 7/13/2009 2.03 Major Changes made for template compliance 8/28/2009 2.04 Editorial Revised and edited the technical content 11/6/2009 2.05 Editorial Revised and edited the technical content 2/19/2010 2.06 Editorial Revised and edited the technical content 3/31/2010 2.07 Major Updated and revised the technical content 4/30/2010 2.08 Editorial Revised and edited the technical content 6/7/2010 2.09 Editorial Revised and edited the technical content 6/29/2010 2.10 Editorial Changed language and formatting in the technical content. No changes to the meaning, language, or formatting of the 7/23/2010 2.10 None technical content. 9/27/2010 3.0 Major Significantly changed the technical content. No changes to the meaning, language, or formatting of the 11/15/2010 3.0 None technical content. No changes to the meaning, language, or formatting of the 12/17/2010 3.0 None technical content. No changes to the meaning, language, or formatting of the 3/18/2011 3.0 None technical content. No changes to the meaning, language, or formatting of the 6/10/2011 3.0 None technical content. 1/20/2012 4.0 Major Significantly changed the technical content. No changes to the meaning, language, or formatting of the 4/11/2012 4.0 None technical content. No changes to the meaning, language, or formatting of the 7/16/2012 4.0 None technical content. 10/8/2012 4.1 Minor Clarified the meaning of the technical content. 2/11/2013 4.2 Minor Clarified the meaning of the technical content. 7/30/2013 4.3 Minor Clarified the meaning of the technical content. 3 / 73 [MS-OCSPROT] - v20210817 Skype for Business and Skype for Business Server Protocols Overview Copyright © 2021 Microsoft Corporation Release: August 17, 2021 Revision Revision Date History Class Comments No changes to the meaning, language, or formatting of the 11/18/2013 4.3 None technical content. No changes to the meaning, language, or formatting of the 2/10/2014 4.3 None technical content. No changes to the meaning, language, or formatting of the 4/30/2014 4.3 None technical content. 7/31/2014 4.4 Minor Clarified the meaning of the technical content. No changes to the meaning, language, or formatting of the 10/30/2014 4.4 None technical content. No changes to the meaning, language, or formatting of the 3/30/2015 4.4 None technical content. 9/4/2015 5.0 Major Significantly changed the technical content. 7/15/2016 5.1 Minor Clarified the meaning of the technical content. No changes to the meaning, language, or formatting of the 9/14/2016 5.1 None technical content. No changes to the meaning, language, or formatting of the 9/29/2016 5.1 None technical content. 2/10/2017 5.2 Minor Clarified the meaning of the technical content. 4/27/2018 6.0 Major Significantly changed the technical content. 7/24/2018 7.0 Major Significantly changed the technical content. 8/28/2018 8.0 Major Significantly changed the technical content. No changes to the meaning, language, or formatting of the 8/17/2021 8.0 None technical content. 4 / 73 [MS-OCSPROT] - v20210817 Skype for Business and Skype for Business Server Protocols Overview Copyright © 2021 Microsoft Corporation Release: August 17, 2021 Table of Contents 1 Introduction ............................................................................................................ 7 1.1 Glossary ........................................................................................................... 7 1.2 References .......................................................................................................