Transcript Powerpoint file

Feature Interaction:
An Industrial Perspective
Greg Utas
May 17 2000
Topics
 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?
 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
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Two definitions
 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
 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
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Standards
 More standards => more interactions and interworkings
 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.
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Intelligent Network concepts
 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
 Protocol independence
 services need not understand access (UNI) or interworking (NNI)
protocols
 limits the range of services that can be developed
 Application Programming Interfaces (APIs)
 AIN, TAPI => JAIN, JTAPI
Nothing fundamental has changed.
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Home Call Server
 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
 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
 Separation of access provider and service provider
A Home Call Server increases the degree of
interaction and interworking because of differentiation.
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Intelligent terminals
 The power of terminals (“clients”) increases, and so
more features will be developed there...
 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.
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Downloadable services
 Download services to terminals, SSPs, or SCPs
 for example, MExE and WAP for mobile terminals
 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.
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Bearer path architecture
 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.
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Security and privacy
 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
 Firewalls in IP-based networks are a new obstacle
Security and privacy are new dimensions that increase
the complexity of interactions and interworkings.
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Quality
 Increased differentiation
=> cursory interoperability
=> reduced quality of interactions and interworkings
 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.
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Conclusion
 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?
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