Submarine cables have long lifetimes, and a fibre-optic cable installation, including the software and firmware, needs to be maintained for decades. Not all of the equipment is readily accessible, with a large number of installations at geographically remote locations. Sometimes the equipment can be at the bottom of the ocean.
With those sorts of timescales, it’s inevitable that newer network technologies emerge during the lifetime of the cable.
The Project
Our client, a global communications equipment provider, wanted to upgrade their network management system to TCP/IP, but still manage legacy systems in the field. They needed to build a high-reliability interface “bridge” to upgrade their cable power feed equipment installations.
Our client asked us to develop the interface bridge software. It needed to act as a proxy for newer TCP/IP-based network management elements and multiple monitoring and control panels, and allow them to communicate with earlier cable equipment.
The interface bridge software was expected to run on an embedded platform Computer-on-Module (COM) and bespoke PCB assembly, and needed to support more than one variant of power feed equipment.
The key software requirements were:
- reliability, as it was expected to run for years, often in remote locations, without requiring a reboot;
- the ability to recover to a functioning state as quickly as possible in the event of an error; and
- timely and accurate relay of control / monitoring requests to and from the unit.
The main constraint was the use of the existing communications protocol which assumed a single master architecture.
Our Role
We worked in partnership with the client’s senior engineers to define the requirements for the system, including the Computer-on-Module integration with the existing backplane and other external interfaces.
We prepared an object-orientated software design with careful consideration of objects and their interfaces, and carried out a rigorous internal design review prior to beginning the implementation phases of the project.
This was time well-spent, as it meant that we could write the software as a cohesive whole, with little rework required during the testing, integration and handover.
We provided the full software implementation and embedded software image for the rugged embedded Computer-on-Module (COM) interface board, enabling the newer network management software to communicate with the earlier power feed equipment installations.
Our solution multiplexed requests from multiple monitoring channels onto a single legacy channel.
The Technology
In conjunction with our client, a rugged embedded Computer-on-Module was chosen for the highly-optimised processing power and the low profile required to fit into the existing power feed equipment shelf.
We established the temperature profile of the board early on in the project to ensure that the extreme temperature operating requirements in the field would be met.
We selected an appropriate embedded operating system with a long support lifetime.
As this was new software, we could take advantage of C++ and the boost libraries, which supported a consistent memory and fault management strategy.
Underlying operating system services enabled the interface software to run for prolonged periods without maintenance, while allowing future upgrades to the feature-set with minimal interference to the software.
The Benefit
We were able to perform an independent review of hardware shelf integration, and the architecture and process.
Our software meant that our client was able to maximise the profit and lifetime of an existing product line.
We delivered a high-reliability design and implementation.
We backed it up with high-quality documentation and engineering support manuals.
