What are Zero Clients?
You maybe familiar with a thin client used in desktop virtualization. There is also something called as Zero Client, also used in desktop virtualized scenarios. In a Zero Client – unlike a thin client – there is no CPU, no local storage, no RAM, no moving parts, and no Operating System. A Zero Client just has a chip with built-in firmware.
In other words, zero clients act as Input/Output redirection units. They send the user input/strokes from keyboard, mouse, etc. to the server; receive data as images (pixels) and display them on the monitor. The processing is totally done on the server-side, but the zero client may employ hardware acceleration and integrate the VDI client into their chip, mainly for performance enhancement reasons.
Zero clients basically consist of a chip, monitor, keyboard & a mouse, but are available in multiple form factors. They depend totally on the back-end server (desktop virtualization set up) and hence cannot work independently. Let us look at important advantages and disadvantages of zero clients.
- Manufacturers say the cost of zero clients is lower than computers or thin clients.
- Zero Clients are easier to configure, deploy & manage. It boots-up quickly (takes just a few seconds). Desktop appears in the same state as left by the user previously.
- Contains no moving parts: more reliable, long-lasting, and runs cooler.
- Consumes only a fraction of energy/electricity when compared to desktops or even thin clients. Many zero clients can be powered by the Ethernet cable via PoE Switches (Power Over Ethernet).
- No data is stored on the zero client. The images received by it are mostly encrypted. So they are better in terms of centralizing security and compliance. Further, it is possible to prevent risk of data theft by disabling USB devices.
- Maintenance is minimum as firmware upgrades/patches are relatively infrequent. Maintenance costs, as a result, are lower.
- Many zero clients support 802.1x network authentication and integrate with card readers for physical token based authentication.
- Zero clients occupy (relatively) less space.
- Rapid deployment – plug and play.
- Many zero clients integrate the VDI client into their chip. Some may employ hardware acceleration on the chip that can manage heavy and specialized processing, if required.
- No sound, quiet operation.
- Some may support fiber connectivity, in addition to copper connectivity to the network.
- They come with many common interfaces like DVI, USB, etc.
- No risk of theft/tampering.
- In Desktop Virtualization, certain solutions use end-user terminal’s capability to render graphics, etc. This can only be done in a limited way, using zero clients.
- Availability and performance depends on network/Internet connection. Can a zero client support offline access when the network is down?
- OS and VDI licensing costs may still apply to zero clients, depending on which software(s) you choose.
- Unified Communications and other desktop-dependent applications maybe difficult to achieve with zero clients.
- Single vendor lock-in: User’s negotiating ability maybe diminished during expansion as they can approach only one vendor to buy more units.
- Unlike zero clients, with thin clients it maybe possible to change from one vendor to another. Zero clients are designed only for one of the three VDI protocols (mostly): PCoIP, HDX, Remote FX, right at the factory-level.
- Multiple monitor connections may not be possible with some solutions, even if possible, there maybe limitations on how many monitors can be attached to a single client.
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