Software interoperability in the NGN Service layer

1. Software interoperability in the NGN Service layer Dave Penkler CTO OpenCall, HP

2. Presentation Outline • Why Software Interoperability for NGN • Preliminaries • NGN Service layer • Software Portability versus Interoperability • Protocols versus API’s • APIs and Protocols in the service layer • Conclusion HP

3. Why Software Interoperability for NGN • Interoperability from the user’s perspective: • Ability to create, use and share information and services on different devices with software from different vendors over multiple networks and service providers. • The value is in the applications • Application innovation happens elsewhere: • Standard developers can hardly anticipate all useful applications and business models • The cost, complexity and delay incurred by striving for convergence at the protocol level will likely kill aspiring NGN business cases. • Programmability of the network = Application innovation for NGN • Clear separation of network and application functionality • Defining abstractions of network capabilities as software interfaces • The interface specifications are open and implementations testable for interoperability • Software functions can be invoked transparently across the network • Restore end to end transparency: protocol & SW interoperability HP

4. Next Generation Network Architecture Common Service Infrastructure (e.g. IMS) Adapted from ITU-T FGNGN-FRA Service stratum Network Application Interface Application Functions Service User Profile Functions Network Resources & Capabilities I/F Service and Control Functions Management Functions Transport User Profile Functions Network Transport Control Media Attachment Functions Handling Control Functions Functions Other Gateway Customer Other networks Functions Functions networks Access Access Access Core Transport Edge Transport Core Transport Transport Functions Functions Functions Functions functions functions NNI UNI Transport stratum Control Transport Network Independence Access Network Independence Media Management HP

5. Software Portability vs Interoperability • Software portability • Code that can be deployed and executed on different systems with the same behaviour • Source code: portability ensured by compiler and libraries • Binary code: portability ensured by application binary interface • Network code: (Code that can be sent over a network and executed at the destination) portability ensured by run-time environment (eg: Java, ECMAscript, XML scripts) • Software interoperability • Code developed to one side of an interface specification that can interact as expected with heterogeneous implementations the of the other side either locally or remotely. HP

6. Application Programming InterfacesvsProtocols • NGN supports the delivery of end-user services through application servers, rather than directly embedding services as capabilities in the control protocols • Protocols define what bits are sent on the wire between 2 entities – Technology neutral. • APIs are defined in terms of the operations and data-structures exchanged between 2 software entities either locally or remotely. • API’s are implemented as a service interface to protocols or as a higher level interface usefully combining a number of lower level or remote peer functions. • Applications interact with users, network resources and with one another through API’s • NGN and IMS standards development is primarily done at the protocol level. • Adopting all IP and IETF protocol standards is not enough to enable end to end network transparency. • SIP protocol specs for IMS are already horribly complicated • Web Services: A viable technology neutral way to define interfaces and achieve software interoperability over the network. HP

7. API complexity trade-off Remote Invocation Application Number of Programmers Application Programming Simplicity Implementation Complexity of API Level of Abstraction Level of Expressivity of API Service Enabler API Application Function Service Building Block API Middleware High Level Protocol API Low Level Protocol API Protocol Implementation Transport Network Functions HP

8. APIs and Protocols in the Service Layer Applications in service provider and terminal domains External ASPs & IT services Network applications and capabilities, exposed via XML and Web Service interfaces (e.g. ParlayX, OMA web services). Interactive Voice & Video Applications Instant Group Communication Applications Next-Generation Messaging Applications Frameworks for Network Applications Network Application Layer Common frameworks for service provisioning and management Network Resources & Capabilities exposed as API’s or protocols Device Capabilities Media Processing, Media Control, Media Storage Identity Management Authentication Authorisation Subscriber Profile Management Billing & Rating User Information Management (presence, contact list, location) Network Resources IMS Core Network Circuit Switched Core Network Packet Switched Core Network Core Network HP

9. Conclusion • To enable innovation the NGN must be programmable from the edge. • Expose network resources, capabilities and applications as standard API’s • End to end network transparency • Simple protocols • Facilitate protocol and software interoperability • User expects things to work the same everywhere • Software interoperability is key • necessary but not sufficient HP

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