Virtually speaking: Smart architectures for smart home gateways
However, the plethora of IoT devices now being introduced to our homes already looks to be unsustainable. This is creating a formidable challenge for operators and service providers wishing to manage and deploy IoT services, with additional hardware necessary to support an array of differing communication mechanisms.
In this article I will discuss the impact of IoT on the home gateway and consider how a new approach using virtualization not only helps solve those challenges but also enables all companies in the delivery chain access to advanced gateway architectures that drive new business opportunity.
The challenge in the evolution of the smart home
Consider a typical home network topology today. Invariably there’s a home router or gateway as the central hub of the network, whose primary task is to manage connection to the broadband service. Almost certainly the gateway also creates one or more Wi-Fi networks for devices to access Internet services. This is sufficient for home multimedia products such as tablets, smart TVs, PCs and so on, and we’ll no doubt see a steady transition to 802.11ax as the new standard is rolled out, promising even faster data transfer.
But Wi-Fi is not the only radio standard. It is usually considered too heavyweight for smart home devices comprising sensors and controllers that do not require the high bandwidth that Wi-Fi offers. Likewise, it’s often unsuitable for products that demand connectivity over larger distances than Wi-Fi can typically cover via a single access point.
So, IoT and smart home products employ more appropriate standards such as ZigBee, Z-Wave, Thread and Bluetooth, chosen to provide the ideal balance between power consumption, bandwidth and coverage for specific applications. While some of the more advanced home gateways are now integrating additional radio standards, this isn’t commonplace and instead service operators supply small form-factor IoT hubs to provide the necessary connectivity, which are often little more than an Ethernet bridge to their chosen radio technology.
This is an easy solution but it inevitably leads to several IoT hubs connected to the existing home router, usually one for each service. This increases the amount of hardware in the home, which is potentially confusing for the consumer, and is also environmentally unfriendly. Furthermore, it also creates potential for unreliable connectivity due to overlapping networks: after all, there’s no guarantee that two different IoT hubs won’t be using the same radio frequencies and networking protocols.
A solution to this would be to absorb that hardware into the existing home gateway, however, doing so is not without challenges.
The integration challenge
Adding IoT hubs to deliver smart home services has been the favoured mechanism because those hubs offer a highly-targeted, cost-effective solution, with dedicated processing resource. Furthermore, a reasonable level of security is afforded by the fact that the hardware is typically designed for a single purpose.
Relocating that hardware – specifically the radio technology – into the home gateway is relatively straightforward. More challenging however is the massive software integration exercise this creates. Diverse IoT ecosystems, such as home security, smart lighting and e-healthcare, must now be combined within the gateway, each requiring multiple standards, each with their own resource requirements, and possibly even using different operating systems. And this doesn’t even begin to factor in the extended development time due to quality assurance and testing. In summary, it’s complicated!
But this assumes a single software environment that maintains essential core gateway functions alongside smart home services such as home security, smart lighting, and e-healthcare solutions. The challenge is providing a secure environment in which all these applications can coexist and run independently within the home gateway. In essence, we need a new architecture: one that is flexible enough to enable all use-cases, easy to develop software for, simple to test and validate, extensible so as to offer new services, and one which also provides enhanced security. We need virtualization.
Enter the virtualized world
Virtualization has been employed in the enterprise server market for many years with the notion that a single server can run multiple software environments and services simultaneously, and by doing so reduce the associated running costs and capital expenditure on the hardware. Imagination has uniquely integrated the same technology into its entire line-up of MIPS processors, from the entry-level to the high end of embedded systems. MIPS CPUs offer full hardware virtualization, where the chip itself provides all elements necessary to securely boot the system and maintain several virtualized environments, each completely isolated from one another, backed by supremely fast context-switching – all of which are essential in the embedded environment.
In a virtualized system a privileged piece of code called the hypervisor is run in place of the native operating system. This is established through the usual mechanisms of secure boot managed by hardware-enforced root-of-trust, which guarantees that the hypervisor is the first trusted code to execute on the processor. The hypervisor manages access to all processor cores and resources in the system including peripherals, the radio communications and external memory; it enables the creation of virtual machines, or “containers”, each running an independent software environment. With such a system based on the MIPS architecture, it is possible to create up to 31 virtual environments on the I-Class cores designed to target this application. Through the hypervisor, multiple operating systems can run concurrently, each in its own isolated virtual environment; each behaving as if it had direct access to the underlying hardware and memory subsystem.
In the context of a home gateway, this architecture allows for the essential core gateway software to run in its own container. The system can then introduce additional containers for smart home services, each of which is secure and isolated from every other service, all of which believe they are running natively on the hardware. This means that services can use disparate operating systems, whichever are appropriate. They no longer have to use a common kernel or driver set, so can be running different versions of Linux if necessary; alternatively one or more services might employ a real-time operating system (RTOS). These can each run alongside the existing services unaltered with no requirement to port them to a common operating system.
In our example, we have the core gateway software running securely in its own virtualized environment. Another container is running concurrently, managing a home security system based upon a RTOS. The third container provides a home control service such as smart lighting and heating. Access to the radio resources on the gateway (be this Wi-Fi, ZigBee, Bluetooth, etc.) is multiplexed by the hypervisor. This allows services to use single unified radio frequencies and improves utilization of the existing radio spectrum.
The architecture is flexible and extensible, allowing up to 31 containers to be created or destroyed as services as added or removed. Imagination already has companies building a solution whereby the broadband side of the gateway is maintained separately from the home Wi-Fi and ZigBee networks. This brings an opportunity for firmware updates on either side while the gateway remains operational. New IoT services may be introduced without detriment to existing services already running on the gateway; likewise service updates can be achieved on a per-container basis without necessity to reboot the entire system as a whole, so operators can maintain service continuity during upgrade.
Virtualization doesn’t just benefit engineering; operators win too!
The transition to a virtualized architecture brings with it many benefits, not just for those tasked with manufacturing home gateways but also tangible revenue generating opportunities for operators that embrace the technology.
Virtualization enables, and indeed encourages, software to be modularized. This significantly reduces engineering development costs while minimizing quality assurance and testing, both of which deliver a time-to-market advantage. More advantageous, the massive software integration challenge presented by assimilating smart home services into the home gateway is largely avoided: software that would ordinarily be deployed on the IoT hub can instead be executed on the home gateway in its own container, secure and isolated from all other elements in the system, and with access to the radio communication technology, just as if running on dedicated hardware. And, of course, those essential core functions of the gateway remain in their own protected domain, isolated from all other software running on the system, so in the unfortunate instance where a service is compromised through hacking, there’s no mechanism available to pivot across into other domains to disrupt operation of the gateway or other services running on it.
From the operator perspective, a virtualized gateway affords a wider choice of IoT services. No longer do they need to select preferred IoT vendor solutions ahead of time and then embark on a lengthy integration effort with their gateway partners; instead they may choose third-party service providers throughout the lifetime of their consumer premises equipment, offering those providers option to integrate their software container into the existing home gateway rather than purchasing and deploying additional IoT hubs.
This further benefits the consumer, who often does not understand the technology and prefers not to have yet more equipment hanging off the back of their router, consuming power and requiring maintenance. True, the gateway must have all popular radio communications networking technology pre-integrated, adding to the bill of materials. However, the benefits of an operator being able to effectively manage those networks, multiplexing radio frequencies to improve spectrum utilization and deliver highly reliable smart home services, quickly outweighs the cost of integration.
This is especially true when factoring in the associated costs of running help desks because the customer misconnected something, or recovering the costs of all consumer premises equipment throughout the customer’s contract.
In summary, virtualization of the home gateway is an advantage from both engineering and commercial standpoints. Virtualized architectures ultimately lead to simpler deployments with faster time-to-market, an associated reduction in costs, a broader selection of third-party services with capability for an operator to deploy dynamically, plus a single gateway that is managed exclusively by the operator leading to increased customer satisfaction.
Imagination is working with several partners to deliver these benefits using MIPS processors, and we expect to see a new generation of home gateways harnessing the power and potential of virtualized architectures.
Further information
Want to know more? You’ll find further information on MIPS Processors on Imagination’s website at https://www.imgtec.com. A detailed appraisal of virtualized architectures for home gateways can be found at www.imgtec.com/event/smart-architectures-smart-home-gateways-new-challenges-new-thinking. Additionally, visit prpl for more information on virtualization and security here https://prplfoundation.org/virtualization-security
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