Dennis Smith, David Carney and Ed Morris DEAS Workshop May 21, 2005

Sponsored by the U.S. Department of Defense© 2005 by Carnegie Mellon University

1

Pittsburgh, PA 15213-3890

Dennis Smith, David Carney and Ed MorrisDEAS Workshop

May 21, 2005

Interoperability Issues for Autonomic Computing

© 2005 by Carnegie Mellon University Smith - 2DEAS Workshop

Context for Interoperability

Most modern systems are usually a heterogeneous collection of custom and commercial products

• Integration provided by some third-party technology

Modern systems are seldom expected to function independently• Expected to cooperate with existing systems • The ability to achieve “cooperation” is generally termed

"interoperability“

Elements of these cooperating systems undergo frequent (e.g., upgrades of commercial products)

Thus: boundaries within and between systems beginto blur

• Distinction between a "system of systems" and a single, complex, distributed system disappears


System “C”

We know quite a lot about constructing systems from components (over which we may have little or no control).

Current State of Our Knowledge

We know something about composing systems of systems from individual systems (over which we may have little or no control).

System “B”

We know very little about constructing an interoperable network of systems…the key distinction being that the network is unbounded (or very loosely bounded) and has no single controlling authority.

System “A”

“SYSTEM D”

Unplanned, unexpected, emergent behavior here…


Autonomic Computing Requires Attention to Interoperability Issues

Selected relevant autonomic characteristics:• Reflexivity: detailed knowledge of a system’s

components and their inter-dependencies• Self-configuration: reconfiguring at run-time and

adaptive algorithms can benefit from research in interoperability on “emergent algorithms”

• Evolving: the evolution of systems relies directly on understanding how to add components and systems to an existing system or system of systems


Interoperability Issues That Can Impact Autonomic Systems

• Tests to verify interoperability often fail to identify interoperability shortfalls

• When interoperability is achieved, it is often difficult to maintain as new versions of constituent systems are released

• Planned interoperability between new systems is often scaled back to maintain compatibility with older systems

• Strict specification of standards for achieving desired levels of interoperability is often insufficient because organizations constructing compliant standards often interpret them in different ways


Principles Required to Address Interoperability for Autonomic Systems- 1No clear distinction can be made between Systems and Systems of Systems.• One man’s system-of-systems is another’s system.• The critical factor is less where a boundary might

lie and more where control lies- most systems are now created with some

components over which the integrator has less than complete control

• There will always be new things to integrate into the system.


Principles Required to Address Interoperability for Autonomic Systems- 2

Interoperability problems are independent of domain• Most complex systems in almost every domain are now

expected to interact with other complex systems

Solutions cannot rely on complete information• Classic software engineering practice assumes a priori

understanding of the system being built, including complete and precise comprehension of assumptions, functionality, services, data and quality attribute needs.

• Multiple organizations have multiple—and rarely parallel—sets of expectations about the constituent parts and the entire system of systems


Principles Required to Address Interoperability for Autonomic Systems- 3No one-time solution Is possible • As a result, new approaches are needed to

- vet proposed requirements changes at the system and system-of-systems level

- analyze the effect of proposed requirements and structural changes to systems and systems of systems

- structure systems and systems of systems to avoid (or at least delay) the effect of changes

- verify interoperability expectations to avoid surprises when systems are deployed


Principles Required to Address Interoperability for Autonomic Systems- 4Networks of interoperability demonstrate emergent properties• Emergent properties are those properties of a

whole that are different from, and not predictable from, the cumulative properties of the entities that make up the whole

• In very large networks, it is not possible to predict the behavior of the whole network from the properties of individual nodes. - Such networks are composed of large numbers

of widely varied components (hosts, routers, links, users, etc.) that interact in complex ways with each other, and whose behavior “emerges” from the complex set of interactions that occur


Common Observed Interoperability Problems- 1Need for understanding on scope and mechanisms of interoperability

Divisions of responsibility• Many divisions in responsibility, obligation, and management• Potential results of these divisions:

- Things will fall through cracks- When problems occur, finger pointing can occur

Requirements• Requirements for interoperability are often ill –defined except

to “work together”• Requirements for different components and systems often

continue to evolve

Functionality• Not all capabilities of different versions are compatible• Achieving backward compatibility represents a major

challenge


Common Observed Interoperability Problems- 2Processes (development and integration)

• There is often some degree of misfit between

processes, methods and tools employed by different

contributors to the system

Other potential showstopper issues

• Scalability

• Performance

• Security• Testing


Selected Emerging Research Areas on Interoperability Issues for Autonomic Computing

• Models of interoperability• Evolution of components• Semantic issues • Testing and validation• Migration to net centric services• Impact of joint interoperability and survivability

requirements• Characteristics of interoperability• Implications of Service Oriented Architectures

Dennis Smith, David Carney and Ed Morris DEAS Workshop May 21, 2005

Documents

Transcript of Dennis Smith, David Carney and Ed Morris DEAS Workshop May 21, 2005