1. Feature Interaction: An Industrial Perspective Greg Utas May 17 2000

2. G.Utas - Feature Interaction: An Industrial Perspective - 000517 1 Topics v In the next decade, in emerging networks...  Will the number of feature interactions increase or decrease?  Will the interactions become easier or more difficult to resolve? v New services in emerging networks are largely undefined, so...  look at forces that affect new networks, and the characteristics of new networks, to investigate these questions

3. G.Utas - Feature Interaction: An Industrial Perspective - 000517 2 Two definitions v Interaction: a relationship between two features running on behalf of the same user  for example, the flashhook contention between POTS three-way calling and call waiting  important interactions must be specified v Interworking: a relationship between two features running on behalf of different users  for example, call completion to a busy subscriber  must be specified, because they usually involve different systems

4. G.Utas - Feature Interaction: An Industrial Perspective - 000517 3 Standards v More standards => more interactions and interworkings v Forces that create more standards include  differentiation (competition)  interoperability (interworking)  not invented here  creating barriers to entry (protecting incumbents)  levelling the playing field (disrupting incumbents) These forces will increase both the number of interactions and their complexity.

5. G.Utas - Feature Interaction: An Industrial Perspective - 000517 4 Intelligent Network concepts v Service capabilities  don’t specify services, but rather service building blocks  makes interactions more difficult because they cannot be resolved based on the specific services involved v Protocol independence  services need not understand access (UNI) or interworking (NNI) protocols  limits the range of services that can be developed v Application Programming Interfaces (APIs)  AIN, TAPI => JAIN, JTAPI Nothing fundamental has changed.

6. G.Utas - Feature Interaction: An Industrial Perspective - 000517 5 Home Call Server v In existing mobile networks, services run in the call server where the mobile was located when it originated or received its call  service ubiquity; limited differentiation v Next generation mobile networks may separate the signalling and bearer paths  signalling path goes to Home Call Server first, which runs services  bearer path may first go to Serving Call Server, for route optimization or location-based services v Separation of access provider and service provider A Home Call Server increases the degree of interaction and interworking because of differentiation.

7. G.Utas - Feature Interaction: An Industrial Perspective - 000517 6 Intelligent terminals v The power of terminals (“clients”) increases, and so more features will be developed there... v But the network will still be involved:  interworking  proxy (for unreachable terminals)  group services  stimulus signalling  security, performance, or revenue reasons The number of interactions and their complexity increases because of additional terminal-network interactions.

8. G.Utas - Feature Interaction: An Industrial Perspective - 000517 7 Downloadable services v Download services to terminals, SSPs, or SCPs  for example, MExE and WAP for mobile terminals v Will probably be restricted to content-based services  security and quality concerns  complexity issues, at least beyond the IN call model Will probably be limited to services that introduce few interactions.

9. G.Utas - Feature Interaction: An Industrial Perspective - 000517 8 Bearer path architecture v Addition of ATM and IP networks  transcoding and adaptation must be negotiated  broadcasting (e.g. during mobile handover) requires special support  separation of signalling and bearer paths complicates call intercept (wiretap) requirements  multimedia, however, is a simple change to the connection object model Interactions and interworkings become somewhat more complex for connection oriented services.

10. G.Utas - Feature Interaction: An Industrial Perspective - 000517 9 Security and privacy v Often mentioned as issues for IP-based networks, but they even exist today  privacy indicator for calling number  authentication, ciphering, and aliases (TMSIs) in GSM networks v Firewalls in IP-based networks are a new obstacle Security and privacy are new dimensions that increase the complexity of interactions and interworkings.

11. G.Utas - Feature Interaction: An Industrial Perspective - 000517 10 Quality v Increased differentiation => cursory interoperability => reduced quality of interactions and interworkings v Could this persist?  for a while, if users or service providers lower expectations, but...  emerging products want content  established products want schedule  mature products want quality--assuming that maturity is reached Reduced focus on quality => much less focus on interaction. Continued focus on quality => big focus on system integration.

12. G.Utas - Feature Interaction: An Industrial Perspective - 000517 11 Conclusion v More interactions, and more complexity, resulting from  competition, which drives differentation  interoperability, driven by differentiation  services also being developed in terminals  new dimensions of bearer path design, security, and privacy But will reduced quality expectations allow the interaction “problem” to be largely ignored?