Tuesday, November 2, 2010

Creating Robust Net-Centric Services through Policy


Next Tuesday at TMForum Management World Americas conference in Orlando, I'll be presenting along with Sriram Chakrapani, (Chief, Integration Engineering Division, DISA) a presentation titled Policy Enabled Net-Centric Information Sharing. Due to this, and a whitepaper I'm putting the final touches on titled "Robust Net-Centric Services", I thought it would be an opportune time to write a post discussing the value of policy in defining robust net-centric services.

As integration frameworks, Web Services and Restful applications adequately address how applications get exposed and communicate via SOAP/XML to exchange information with one another in a platform agnostic way. In real-world applications however, security, reliability, routing, bandwidth conservation, versioning and other requirements still have to be dealt with and in turn severely impact the loosely coupled nature of net-centric services.

For tactical edge deployments as well as disadvantaged (in one way or another) enterprise deployments these requirements are vital as web services and consumers undergo challenges and need to operate in a constantly changing environment. Bandwidth and connection state among other things require web services to have situational awareness where they can adapt to a constantly changing scenario. A simple example of such a change could be that a consumer and service are in use in a connected state to DISA Net-Centric Enterprise Services (NCES) and then become disconnected due to a kinetic or cyber attack. In this disconnected state the information exchange must continue to operate seamlessly by moving to a fall-back set of requirements (security, transport, reliability, etc.), locally deployed core enterprise services (machine to machine messaging), and potentially a cached business service. All without impacting the user.

The presentation and paper proposes the concept of “Robust Net-Centric Services” or “net-centric services with a high degree of resilience even when faced with a comprehensive array of faults and/or challenges and inherently capable of reacting gracefully to both internal application changes as well as external environmental changes, all without impacting information exchange”.

Given the distributed and federated nature of robust net-centric services, especially those supporting tactical edge communications; the ability to define robust requirements using policies, which are understandable and interoperable across a variety of implementations while at the same time implemented in a distributed fashion and subsequently easily changed is key to achieving complete information superiority.

The paper and presentation will highlight the four primary challenges to creating robustness. For the sake of brevity, I'm only going to list the four categories in this blog post. Each will be detailed in the paper when it is released.

  1. The availability and robustness of a network
  2. The availability of resources to execute a particular function
  3. Information Assurance (IA)
  4. User Interface (UI)

In order to accommodate the challenges above, it is required that we look back to the fundamental principles of software engineering: flexible systems are achieved by decoupling the variable parts of the implementation from the invariant parts. This variable layer can then be managed without affecting the system invariants. In this, conflicting constraints and capabilities can be reconciled, managed and constantly monitored. For example, performance and response time requirements can be weighed against security, confidentiality and privacy requirements.

Robust Net-centric services employ a deployed policy-driven and intelligent run-time capability to provide a Policy Layer, so that applications can be built based on their perspective business requirements, allowing applications to be deployed without knowledge of requirements they might face during certification, deployment, or during operation.

The Policy Layer provides a light-weight federated on-ramp to the enterprise and to the particular enterprise services in which the application depends upon, and facilitates a policy oriented approach to connectivity, and integration to locally deployed resources as well as those available on the enterprise network. This layer architecturally is made up of two fundamental concepts a Policy Enforcement Point (PEP) and a Policy Application Point (PAP). The following diagram illustrates how policy and a run-time policy enforcement and application capability could be deployed to allow for robustness in the face of a comprehensive array of requirements, and or situational challenges.

Through Policy enablement, operators can create and modify integration, caching, access control, privacy, confidentiality, audit logging and other such policies around the business services, without interfering with the development of the services themselves. This is the first step towards real-world implementation of loosely coupled SOA and a necessary step in preparation for robustness.

Email me if you would like to receive the paper on robust net-centric services when it is completed or if you have unique challenges/situations that you would like to see conveyed in the paper. If you would like to learn more about how Layer 7 products support the vision of robust net-centric services today, contact your local sales government representative. I hope to see some of you in Orlando!

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