DCL's portable software products run within a portable operating environment called the N-BASE. N-BASE, which has been shipping with DCL portable products since 1991, provides many benefits to developers including
- straightforward and rapid integration
- flexible integration options
- diagnostic capabilities
- a framework for creating highly available architectures.
The following is a summary of N-BASE benefits.
- Straightforward and rapid integration. All of the DCL's networking protocols come pre-ported with the leading
Operating Systems including Linux, LynxOS, OSE, QNX, Solaris, UNIX, VxWorks and Windows. These pre-ports, which are fully supported by
our customer service engineers, dramatically reduce integration effort and time.
Furthermore, the integration required for the management and data planes are well documented with open and back compatible APIs which require no changes to the core stack. Reference applications of these common ports are available to further reduce integration effort.
- Flexible integration options. For those developments where there is a need for further customization, the N-BASE
provides your developers with the options that can maximize system performance and comply with modular system architectures. For
example, Data Connection's portable software may run under different scheduling models without change. These include single or
multi-threaded tasks, symmetric or asymmetric multi-processors and distribution of function over multiple processors and operating
system instances. For more information on N-BASE please see the Overview of N-BASE.
- Creating a comprehensive testing and diagnostic environment. The N-BASE provides development services that help us
(and our customers) test every aspect of the code and enable you and your customers to collect complete diagnostics with ease.
- Delivering resilience and high availability. N-BASE's modularity is designed to easily integrate and augment the high availability architectures developed by our customers. N-BASE, coupled with DCL's High Availability Framework, enables systems to be implemented without a single point of failure, thereby allowing 5 or 6 nines availability to be achieved.
Overview of the N-BASE
The previous section provided an overview of the benefits of N-BASE. This section provides a description of the functions that deliver these benefits.
Typical Operating System Environments
The N-BASE is common to all Data Connection's portable protocol software (including packet and optical MPLS, IP routing, MGCP/Megaco/H.248, SIP, SBC, ATM and SNA) and has been ported to many software and hardware environments, including Chorus, Integrity, Linux, LynxOS, Nucleus, OSE©, pSOS©, QNX, Solaris / SunOS, UNIX©, VxWorks / VxWorks / Tornado©, Windows, and proprietary OSes.
Data Connection provides a pre-ported version of the N-BASE for a number of these environments, including Linux, LynxOS, OSE, QNX, Solaris, UNIX, VxWorks and Windows. This list is regularly being updated, so please contact Data Connection for up to date information. For other systems, we provide a sample version of the N-BASE, which is straightforward to port to virtually any operating system.
Messaging and Scheduling
- Clean architecture. All of Data Connection's portable protocol software is broken down into distinct components
that can be run in distinct memory address spaces. A single OS task will typically include multiple components, and in such cases,
message passing between components reduces to a simple function call with a pointer to a block of memory for maximum efficiency.
- Core protocol code stays intact. The N-BASE messaging paradigm allows distribution of components over multiple threads, tasks or processors without altering the core protocol code. This provides customers with the flexibility to provide a method messaging of their choice, without affecting the core code.
Memory Management
- Flexible. The N-BASE uses separate macros for memory management (typically used for local data storage) and buffer
management (typically used for sending messages to other N-BASE components). These provide flexibility in mapping onto underlying
system resources.
- Simple. It is straightforward to customize either the memory or buffer allocation code to use different schemes
simply by re-vectoring the N-BASE macros. The N-BASE architecture supports static memory allocation as well as mapping
N-BASE buffers directly onto native operating system buffers, even if they are fragmented.
- Reliable. The sample N-BASE includes extensive memory diagnostics to detect overwriting, leaks, and access to memory or buffers after they have been freed. These can optionally be built in (for example, during initial integration) to speed up customer development.
Problem Determination
- Message tracing is a hugely powerful tool that records every message exchange between N-BASE components. This can be analyzed off-line using the IPS Trace Tool to produce a graphical view of the data flow, with the ability to zoom on any message to get an interpreted breakdown of every field value in a message. It can also be used to replay messages to reproduce problems off-line. Please see Diagnostics for more details.
Testbed
- By re-vectoring all interactions between Data Connection's portable protocol products and the underlying operating environment,
Data Connection has developed an extensive Testbed that minutely controls scheduling, timers and error returns from all OS and
environment events. Data Connection uses this intensively during development, and each night as part of an extensive regression test
tool.
- The testbed is typically combined with other diagnostic tools such as memory verification to help ensure that the code Data Connection delivers is of the highest quality.
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