There are literally hundreds of different types of client devices that can be used to access MetaFrame XP environments via ICA sessions. While that list is always changing and it's not practical to discuss all of them here, these client devices can be broadly broken down into four groups:
- Traditional computer workstations, including standard Windows PCs, Macintosh computers, and UNIX workstations.
- Traditional computers, managed as generic dumb terminals. These are usually standard computers, complete with local operating systems and hard drives, that are created with disk "images." If one stops working properly, it's replaced with a new computer, or it is "re-imaged." Significant troubleshooting time is not wasted.
- Thin client devices and "dumb" appliances. This includes devices that are usually based on Windows CE, Windows XP Embedded, or Linux on-a-chip. These devices have no local hard drives and typically boot off of servers or have chip-based operating systems. While some of these devices may have local web browsers or terminal emulators, they usually run most applications from backend servers.
- Mobile wireless devices, including dedicated wireless ICA devices and palm-sized computers.
Let's take a look at each of the four families of client devices in greater detail.
Option 1. Traditional Computer Workstations
Traditional computer workstations are currently deployed in almost every organization throughout the world. From a MetaFrame XP standpoint, if traditional computers are out there and they're paid for, then why not use them? MetaFrame XP works very well when accessed from standard computers, whether users access their MetaFrame XP applications through the locally installed Program Neighborhood or through a web portal.
Additionally, because traditional computers have local processors and hard drives, the Citrix ICA protocol can cache certain information and graphics locally, increasing performance, especially over high latency connections.
However, as more applications become server-based and as more companies use MetaFrame XP, traditional computers quickly become overkill for many users. They are expensive to maintain and users often break them through "trial and error" misconfiguration.
Advantages of Traditional Computer Workstations
- Already deployed in most locations.
- Users are comfortable with them.
- Local processor and storage allows for better ICA session performance.
- No perception of "IT is taking this away from us."
- Local, non-MetaFrame XP applications can also be used.
- Many peripherals are available and compatible.
Disadvantages of Traditional Computer Workstations
- Expensive to purchase and maintain.
- Proprietary for each user.
- Difficult to troubleshoot.
- Must be manually configured or complex scripts and policies must be created.
- Require local IT staff for support.
- Prone to being broken by "curious" users.
- Increased risk of "accidental" local data storage, which is not secure and not backed up.
- Target for thieves in unsecured environment.
- Many more options and models make it harder to enforce standards.
- High power consumption.
- Many moving parts that can break or get dirty.
Option 2. Thin Client Devices and Appliances
Thin client devices and appliances are purpose-built machines used primarily for accessing server based computing environments, including web browsing, terminal emulation, and Citrix ICA sessions. These devices usually have no local hard drives or moving parts.
There are several flavors of thin client devices, most easily categorized by their local operating system. Most of these devices run some form of chip-based Windows (Windows CE.NET or XP embedded), Linux, or Java. In order to connect into the MetaFrame XP environment, they therefore need to have the appropriate local ICA client software installed.
There are several advantages to using thin client devices. Because they don't have any in-depth local configuration, users are not able to break them as easily. They have few (if any) moving parts, which means that there is less to break. If something does break, it's usually cheaper and easier to replace the entire terminal.
For example, one company headquartered in Euclid, Ohio has manufacturing facilities in Ontario, Canada. Their entire shop floor is run off of applications on MetaFrame XP servers located in Euclid. All application access in Canada is done via thin client devices. Due to the harshness of the manufacturing environment, traditional PCs were always breaking. The thin client devices they chose had no moving parts-not even cooling fans-so they don't break nearly as often. This is especially nice because there is no IT staff in Canada. When a thin client device does break, the shop foreman goes to the closet and grabs a replacement terminal. The user connects back into his session right where he left off with only a few minutes of total downtime.
However, be careful that you're not fooled by the seemingly endless advantages of thin client devices, because there are several major drawbacks.
First and foremost is the fact that with thin client devices, all major processing must be done somewhere else. With full-blown PCs, you have the option of running applications centrally. With thin clients, all applications must be run centrally. Do you, as an administrator, really want your clients surfing the web or writing email to their kids with valuable server processing time? Of course, many thin clients now have local browsers and local email programs, but you get the idea.
Advantages of Thin Client Devices
- Low maintenance costs. If one breaks, throw it away, plug in a replacement, connect back into MetaFrame XP, done.
- No local user troubleshooting.
- No local IT staff is needed.
- Little-to-no local user configuration, so users can't break them (as easily).
- Low power consumption.
- No black market value, so they're less likely to be stolen.
Disadvantages of Thin Client Devices
- Less flexibility than PCs.
- Essentially, all applications must run through host server.
- If they are purchased to replace PCs, people will be upset. ("We just spent $2500 on new PCs, and now they're replacing them?")
- In politically charged environments, users perceive that their full PC's are being "taken" from them.
Thin client devices are great, but unless you have a compelling reason not to use PCs, be careful of the "nothing" approach (as in "all or nothing") that you get with thin clients.
Option 3. Traditional Workstations, Managed as Thin Devices
It is possible to combine the traditional computer workstation hardware with the management style of thin client devices to create a solution that has some of the advantages of each.
This entails keeping full computer workstations for every user, but building a standard workstation image that is deployed to all users. All of the applications (except maybe a web browser) are server-based. The idea is that if a computer workstation breaks, a new hard drive or new workstation can be brought in to replace it.
One company that did this created a "five minute rule." Basically, the desktop computer technicians would visit an end user whenever they had a problem and called the helpdesk. If it was something simple, they fixed it. However, if the desktop technician could not fix the problem within five minutes, the user's computer was wiped clean and a new image was put on.
This worked well because all of their applications were delivered via MetaFrame XP and NFuse, and all of the users' data was stored on the network. All of the users' computers in the entire company had the same image, which was just a base operating system, a web browser, and the ICA client software.
A very popular trend right now for accessing MetaFrame XP applications is to use your current user workstations with a Linux image and the "five minute rule."
Advantages of Traditional Workstations Managed Like Thin Clients
- Current hardware can be utilized.
- Efficient use of time for IT staff.
Disadvantages of Traditional Workstations Managed Like Thin Clients
- The hardware still breaks.
Option 4. Mobile Wireless Devices
"Mobile wireless devices" are actually a legitimate option when deciding how your users will access MetaFrame XP applications. As with all mobile wireless devices, the primary drawback is still battery life. There are really two classes of wireless devices, LAN devices and public WAN devices.
LAN devices are usually laptop computers or Windows CE / Pocket PC devices with 802.11 wireless network cards. Although there are some companies with wireless devices purpose-built for Citrix ICA sessions, (similar to wireless thin client devices), they are not widely used because they are expensive and generally geared towards specific vertical markets. (Hermetically sealed for healthcare, built in barcode readers for warehouses, etc.) Most people just buy full-blown laptops with wireless LAN cards.
The public wireless WAN is where the real fun begins (for true geeks). The wireless public WAN is the system that you pay a monthly access fee to use. There are many networks throughout the world, and most are based on CDPD, CDMA, PCS, GPRS, or similar networks. There are millions of palm-sized computers out there today, and most of them can run the Citrix ICA client. They can be used for wireless, go-anywhere access to the Internet.
Advantages of Mobile Wireless Devices
- Access to critical applications from anywhere.
- Very, very cool.
Disadvantages of Mobile Wireless Devices
- Expensive service (US $30-$100 per user per month).
- Tiny screens on devices.
- Do we really need to access our applications on the golf course?
- Battery life.