Types of appliances
Consumer-grade versus enterprise equipment
Many home users are very familiar with appliances, if not with the term, in the form of wireless routers, small hardware firewalls, print sharing devices, network attached storage, etc. These devices are small and inexpensive but are not generally scalable, secure, reliable or flexible enough to meet the needs of medium to large organizations.
Commodity hardware versus specialized processors
Physical appliances intended for enterprise deployment have two basic types:
- Commodity server hardware, with pre-installed software.
This means they run a standard type of CPU (Intel/AMD), an off-the-shelf OS (Windows or Linux) and common applications (IIS, Apache, MySQL, MSSQL, etc.).
- Specialized hardware components.
This normally means inclusion of at least one application-specific integrated circuit (ASIC) to perform some specialized function at very high speeds. Commonly found on firewalls, load balancers, malware scanners, etc.
The commodity hardware approach serves mainly to reduce the initial setup and configuration effort for organizations deploying the product. "Inside the box" is just a traditional software server, assembled and supported by the vendor.
Specialized processing hardware is used mainly where the performance characteristics of the system cannot be easily reached with a conventional server. This is typically required in the context of specialized networking equipment, such as SSL processors, virus scanners, application firewalls and more, all of which must perform complex at "wire speeds" -- 1Gbps or more.
The main benefits promoted by vendors who sell solutions in the form of appliances are:
- Easy installation:
The operating system and application software are pre-installed, reducing initial installation effort. The application software is likewise pre-installed and to the extent possible also pre-configured.
This is only a significant advantage for applications that require minimal integrations with existing infrastructure and minimal process configuration. Where such integration or configuration is significant, removing a few hours' work to install the runtime platform is inconsequential.
- Fewer skills required:
The simplified installation and configuration lead to scenarios where fewer IT skills are required to implement the solution. This is particularly true where the application is quite simple and requires little or no further configuration beyond initial activation.
- Sole-source technical support:
Any questions about hardware compatibility or operating system patches are eliminated when a single vendor supports every "layer" of the solution, starting with hardware and ending with the application software.
- High performance specialized hardware:
In the case of specialized processing hardware, the additional and overriding benefit is increased performance. Note that this is not generally true for commodity hardware bundled as an appliance -- this advantage is only relevant where the appliance incorporates specialized hardware, most often to provide a specialized network infrastructure function.