Objectives
The network appliance concept can hardly be classified as new or revolutionary in these days. However, the concept itself hasn’t changed a lot since its inception – the currently available offer for SOHO markets can be reduced to three categories: thin clients, NAS (Network Attached Storage) devices and multi-purpose IP gateways. In fact, one of the first network appliances to gain wide acceptance was the Cobalt Qube – the system was itself little more than a clever mix of fancy aesthetics, standard hardware, a good management interface and Open-Source software brought together to provide IP-related services out-of-the box and with minimal user intervention. The Qube could be configured to act like an IP gateway (with routing and firewalling capabilities) or to perform as a SMTP, HTTP, HTTP or FTP server. When Cobalt was bought by Sun Microsystems, the Qube concept was abandoned after having paved the way for a myriad of derivatives from other players in the field, albeit doing essentially the same things and providing little or anything else new. However, the fact that the Qube was internally a x86 PC must not be understated since it was one of the critical factors that led to its success (because of the wide availability of tools and software for the platform), and was simultaneously one of the reasons of its demise (with competition from other manufacturers, Cobalt (and later Sun Microsystems) did not manage to keep its technical advantage, by making the product evolve in a way it was potentially capable of.
Another interesting fact about currently available network appliances is that they are designed with any or little dependability and availability concerns in mind. Even if the groundwork for implementing such mechanisms is already established, nothing has been done to integrate the results of such efforts in currently available products. PreOS technology can be taken as an example of such situation – despite of being an adequate solution for enabling remote-controlled automatic recovery procedures, no products resorting to such mechanisms are known, at least to present date.
Previously acquired experience of using and developing PreOS technologies has convinced us of its relevance in the context of network appliances and, among them, the Intel PXE (Preboot eXecution Environment) protocol should be considered as being of particular interest. Despite the fact of being originally developed as a means to allow the deployment of operating systems on computers across a LAN, we envisioned that it could also enable the possibility of Incorporating self-healing and recovery capabilities on regular desktop PC’s. Following the same line of thought, enabling PreOS (and particularly PXE-alike) capabilities on network appliances would constitute a giant leap towards better manageability and resilience of these devices.
Apart from the traditional role of being simple network interface and/or access point devices, new perspectives arise for network appliances as a result of the increasingly available bandwidth on SOHO environments (through ADSL, Wireless or Cable connections). Faster and better network connectivity with lower latency is an essential requirement to implement new services that will inevitably increase the need for a more evolved network appliance concept, capable of providing video streaming, IP telephony, and videoconference or telepresence capabilities, among others. Countries like Japan have already witnessed such revolution – DoCoMo was forced to create a new prefix (050) with 8-million associated telephone numbers to accommodate a giant wave of VoIP users. In this context, the SOHO network appliance should be on its way to evolve to some sort of media and communications hub providing a diversity of services to the user.
The global objective of the DOMUS Project is to study the suitability of PC-based platforms to build cost-effective multi-service gateways for the domestic/SOHO environment. The focus is on system manageability, comprising three different levels:
1. Definition of a simple but flexible hardware reference platform built around standard, manageable, low-cost, small form factor of-the-shelf PC components.
2. Introduction of robust preOS management in order to avoid the need for costly local interventions. PreOS management is the key to achieve the same stability of monolithic, embedded gateways without sacrificing the modularity and flexibility associated with the traditional PC architecture.
3. Design of a modular service architecture supporting runtime remote administration. This platform, based on a stripped-down Linux distribution, will support remote service installation/upgrade, remote service administration, unified authentication services and controlled access to hardware resources.