doc.: IEEE /xxxxr0 Submission May 2006 Darwin Engwer, NortelSlide 1 Services and SAPs Notice: This document has been prepared to assist IEEE It is offered as a basis for discussion and is not binding on the contributing individual(s) or organization(s). The material in this document is subject to change in form and content after further study. The contributor(s) reserve(s) the right to add, amend or withdraw material contained herein. Release: The contributor grants a free, irrevocable license to the IEEE to incorporate material contained in this contribution, and any modifications thereof, in the creation of an IEEE Standards publication; to copyright in the IEEE’s name any IEEE Standards publication even though it may include portions of this contribution; and at the IEEE’s sole discretion to permit others to reproduce in whole or in part the resulting IEEE Standards publication. The contributor also acknowledges and accepts that this contribution may be made public by IEEE Patent Policy and Procedures: The contributor is familiar with the IEEE 802 Patent Policy and Procedures, including the statement "IEEE standards may include the known use of patent(s), including patent applications, provided the IEEE receives assurance from the patent holder or applicant with respect to patents essential for compliance with both mandatory and optional portions of the standard." Early disclosure to the Working Group of patent information that might be relevant to the standard is essential to reduce the possibility for delays in the development process and increase the likelihood that the draft publication will be approved for publication. Please notify the Chair as early as possible, in written or electronic form, if patented technology (or technology under patent application) might be incorporated into a draft standard being developed within the IEEE Working Group. If you have questions, contact the IEEE Patent Committee Administrator at. Date: Authors:

doc.: IEEE /xxxxr0 Submission May 2006 Darwin Engwer, NortelSlide 2 Abstract An analysis of the general hierarchy of 802 standards and specifically Services vs. Service Access Points (SAPs).

doc.: IEEE /xxxxr0 Submission May 2006 Darwin Engwer, NortelSlide 3 Outline Assertions stated in wrt SAPs The Broader View Use of SAPs 802 Standards Hierarchy Table 802 Standards Hierarchy Diagram Core Precepts Synopsis Conclusion Summary References

doc.: IEEE /xxxxr0 Submission May 2006 Darwin Engwer, NortelSlide 4 Assertions Stated in Part 1 concern about the misuse of SAPs as APIs in 802 standards Services are end-to-end a SAP is used to invoke a Service –the implementation is to deliver frames to the peer entity –governing reference is ISO/IEC (X.200) an API is a local interface specification [for implementers]

doc.: IEEE /xxxxr0 Submission May 2006 Darwin Engwer, NortelSlide 5 Assertions Stated in Part 2 an example of a *service interface* definition is two devices connected via some medium –if a packet is sent, but fails to be received correctly –then NO primitives occurred –because NO SERVICE WAS PROVIDED Therefore, most 802 standards define service APIs, rather than SAPs i.e. a SAP is an abstraction of the service that was provided according to the OSI reference model. In particular a SAP does NOT need to provide "handshakes", i.e. __.confirm callbacks

doc.: IEEE /xxxxr0 Submission May 2006 Darwin Engwer, NortelSlide 6 The Broader View based on the hierarchy of the 802 reference standards and an analysis thereof. Terms and meaning need to be clarified … –governing reference is ISO/IEC (X.210) “Services” differ from Service Access Points (SAPs) –even though the names are similar “Services” are enumerations of high level ISO Services SAPs are abstract interfaces –defined using X.210 primitives –may or may not describe end-to-end OSI Services –may also define operational precepts of the underlying technology

doc.: IEEE /xxxxr0 Submission May 2006 Darwin Engwer, NortelSlide Use of SAPs commonly uses SAP definitions as an abstract interface specification –this is a service interface built on X.210 primitives –this is NOT an API definition –makes use of the allowed X.210 primitive sequence combinations* –typically no one implements to this interface –used to provide complete operational definitions and descriptions –primitives may result in the invocation of OSI “Services” this is a common SAP objective but is not true in all cases Suspect the same is true for other 802 wireless WGs

doc.: IEEE /xxxxr0 Submission May 2006 Darwin Engwer, NortelSlide Standards Hierarchy Table

doc.: IEEE /xxxxr0 Submission May 2006 Darwin Engwer, NortelSlide Standards Hierarchy Diagram ISO Naming & Addressing Mac Service ISO X.200 OSI Model LLC 802 Overview & Architecture ISO X.210 SAP

doc.: IEEE /xxxxr0 Submission May 2006 Darwin Engwer, NortelSlide 10 Synopsis of content of the core references ISO/IEC (X.200) OSI Basic Model ISO/IEC MAC service definition ISO/IEC (X.210) OSI Service Conventions

doc.: IEEE /xxxxr0 Submission May 2006 Darwin Engwer, NortelSlide 11 ISO/IEC (X.200) Precepts Title = OSI Basic Model Open Service Interconnection (OSI) environment Layers/ layering --> peer entities Communication between peer entities: protocols Properties of service-access-points (SAPs) Data units

doc.: IEEE /xxxxr0 Submission May 2006 Darwin Engwer, NortelSlide 12 ISO/IEC Precepts Title = MAC service definition Connectionless-mode service peer-to-peer data delivery service

doc.: IEEE /xxxxr0 Submission May 2006 Darwin Engwer, NortelSlide 13 ISO/IEC (X.210) Precepts Title = OSI Service Conventions Entities: SAPs, Service Users and Service Providers Actions via Service Primitives –.request requestor.submit –.indication acceptor.deliver –.response acceptor.submit –.confirm requestor.deliver Use case scenarios –4 primitive (full exchange) –2 primitive (.request/.indication) –1 primitive (.indication) –2 primitive (.request/.confirm) - cl local view abstract i/f

doc.: IEEE /xxxxr0 Submission May 2006 Darwin Engwer, NortelSlide 14 ISO/IEC (X.210) Some Examples

doc.: IEEE /xxxxr0 Submission May 2006 Darwin Engwer, NortelSlide 15 Analysis Synopsis ISO services are not defined (in detail), they are just enumerated SAPs are defined in detail with a complete set of primitives SAPs are not just for data OSI services

doc.: IEEE /xxxxr0 Submission May 2006 Darwin Engwer, NortelSlide 16 Service vs. SAP vs. API (an illustrative example) Domain = Our Meeting Room Service = Lighting –i.e. we commit to providing a lighting service SAP = lighting control abstract interface –primitives = on, off, dim, status API = an implementation specific interface –e.g. there is a switch/ dimmer on the wall by the door Note that the Service, SAP and API can be defined independently of each other, i.e. some or all of those can be defined. They are all shown here only for illustration and comparison purposes.

doc.: IEEE /xxxxr0 Submission May 2006 Darwin Engwer, NortelSlide 17 Conclusion SAPs are used for data service –per ISO and SAPs are also commonly used for non-data service abstract interface definitions –this use of SAPs is valid and valuable

doc.: IEEE /xxxxr0 Submission May 2006 Darwin Engwer, NortelSlide 18 Summary Services != Service Access Points (SAPs) –Services are abstract service enumerations –SAPs are abstract interfaces defined by X.210 primitives SAPs can be used for abstract interface definitions other than (N)-layer data services –e.g. MAC management services Potential next steps: –Present the enclosed material to as the position of the Wireless Co-ordination Advisory Group (WCAG) wrt services and SAPs as used in the 802 wireless standards

doc.: IEEE /xxxxr0 Submission May 2006 Darwin Engwer, NortelSlide 19 References ISO/IEC , Information processing systems - Open Systems Interconnection - Basic Reference Model - Part 1: The Basic Model. ISO/IEC :1994, Information technology - Open Systems Interconnection - Basic Reference Model: The Basic Model. ISO/IEC , Information processing systems - Open Systems Interconnection - Basic Reference Model - Part 2: Security architecture. IEEE Std 802.2, Information technology - Telecommunications and information exchange between systems - Local and metropolitan area networks - Specific requirements - Part 2: Logical link control. ISO/IEC :1998, Information technology - Telecommunications and information exchange between systems - Local and metropolitan area networks - Specific requirements - Part 2: Logical link control. ISO/IEC , Information technology - Telecommunications and information exchange between systems - Local and metropolitan area networks - Common specifications - Part 1: Medium Access Control (MAC) service definition. ISO/IEC :1995, Information technology - Telecommunications and information exchange between systems - Local and metropolitan area networks - Common specifications - Part 1: Medium Access Control (MAC) service definition. ISO/IEC , Information Technology - Telecommunications and information exchange between systems - Local and metropolitan area networks - Common specifications - Part 3: Media Access Control (MAC) Bridges. ISO/IEC TR : 1997, Information technology - Telecommunications and information exchange between systems - Local and metropolitan area networks - Technical reports and guidelines - Part 2: Standard Group MAC addresses. IEEE Std , IEEE Standards for Local and Metropolitan Area Networks: Overview and Architecture. IEEE Std ,4 IEEE Standards for Local and Metropolitan Area Networks: Overview and Architecture. ISO/IEC Technical Report :1997(E), Information technology - Telecommunications and information exchange between systems - Local and metropolitan area networks - Technical reports and guidelines - Part 5: Medium Access Control (MAC) Bridging of Ethernet V2.0 in Local Area Networks (previously known as IEEE 802.1H-1997). ITU-T Recommendation X.210 (11/93), Information technology - Open systems interconnection - Basic Reference Model: Conventions for the definition of OSI services (common text with ISO/IEC 10731). ITU-T Recommendation Z.120 (1999), Programming Languages - Formal Description Techniques (FDT) - Message Sequence Chart (MSC) ae (draft 5.1) REVma D statements (

doc.: IEEE /xxxxr0 Submission May 2006 Darwin Engwer, NortelSlide 20 Backup Slides

doc.: IEEE /xxxxr0 Submission May 2006 Darwin Engwer, NortelSlide 21 none

doc.: IEEE /xxxxr0 Submission May 2006 Darwin Engwer, NortelSlide 22 The End (really)