The communications access arena is rapidly changing. This highly dynamic market, with its many emerging standards and protocols, has become increasingly cost-sensitive. Developers must not only bring to market lower-cost solutions, they must do so extremely fast to take advantage of rapidly shrinking market windows. Today, total development cost and time-to-market are every bit as important as system performance.
By bringing together a highly configurable feature set with the extensive software resources of the open-source community, embedded Linux running on off-the-shelf silicon offers designers of access equipment an unprecedented opportunity to develop high-performance systems at low cost. Traditionally, communications equipment designers have relied on proprietary embedded operating systems. By fine-tuning a proprietary operating system to an application, developers can minimize image footprint and maximize performance. So why switch from the comfortable and familiar to Linux? Because, more often than not, designers have had to pay more to achieve these capabilities with a proprietary system.
With the continual evolution of open-sourced Linux and the declining cost of off-the-shelf silicon, developers now have a highly attractive, low-cost option. Off-the-shelf communications processors running embedded Linux can perform both data-plane and control-plane processing. Semiconductor vendors can also optimize the latest versions of Linux to offer new device drivers and a compact footprint. The operating system brings proven reliability and scalability from the server/desktop arena. Furthermore, because it was built on the extensive resources of the open-source community, Linux offers well-documented kernels and development tools.
Loadable modules now help developers quickly tune the Linux image footprint and run-time memory requirements to a specific application. Networking resources have grown increasingly extensive, offering support for IPv4 and IPv6, routing protocols, stream-control transmission protocol, network file systems, point-to-point protocols, stateful firewalls, packet filtering, quality of service, network address translation, and IP compression.
To maximize design flexibility, Linux supports a growing range of hardware platforms including the popular MIPS, ARM, PPC, and x86 processors. Developers can also take advantage of both native and cross-platform development tools to simplify the porting of applications from one platform to another. Through the POSIX/BSD application programming interface (API), developers using Linux can easily integrate many open-source applications, such as open SSL, open SSH, Snort (IDS/IPS), and Samba server, and make use of commercial networking stacks. For security, Linux provides complete IPsec and file system encryption support.
Finally, unlike with proprietary embedded operating systems, developers using Linux have free access to source code. Gaining access to another vendor’s source code is usually prohibitively expensive, if not impossible, simply because no vendor wants to give up control of its primary competitive secrets. With Linux, all developers gain access to the source code. That key distinction not only allows developers to easily debug and modify their system, but by allowing a large number of developers access to the source, it also ensures the bugs are quickly eliminated. The existence of this large, worldwide development community also leads to faster support of new protocols than any single proprietary embedded OS vendor can provide.
That doesn’t mean Linux is free. While the Linux kernel comes at little or no cost, developers must pay a runtime royalty fee per unit for thirdparty technology components and intellectual property. And the cost of development tools, while low, is still a consideration. But the support and tool environment for Linux has grown so dramatically over the past few years that overall development costs are rapidly shrinking.
The rapid convergence of communications and computing is placing a new premium on cost and development speed in the access market. While developers have relied on proprietary embedded operating systems in the past, these changing market conditions are forcing designers to seek out new ways to meet performance goals while reducing cost and development time. While Linux is not the panacea for the communications access software market, its highly customizable feature set and increasingly broad selection of open-source software and tools provides an exciting opportunity to address these new requirements.