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The alternatives for Citrix Presentation Server Part One

Citrix Presentation Server is for many people still synonym with the Server Based Computing technique. Citrix is still market leader in this segment, with a very good product with lot of good features. However nowadays there are several competitors, which also have nice products that can be considered. In this article we will take a look into the SBC market and which products are out there competing with Citrix. 

Introduction




The Server Based Computing technique based on the Windows platform is invented by Citrix. In the early days they licensed Windows NT3.51 and rebuild it this Windows Operating System to the product called Citrix WinFrame. The technique was definitely sensational at that time and became very popular way to deliver applications to end-users.

Microsoft noticed the popularity and made an agreement with Citrix. This resulted in the release of Microsoft Windows NT4 Terminal Server Edition. Later on Microsoft integrated Terminal Services into the default Windows installation. The Microsoft Terminal Server platform was and still is not that rich feature supported that the Citrix Presentation Server product. Reason enough for manufacturers to create a kind of add-on product on top of the Microsoft implementation so it can compete with Citrix Presentation Server.
Let's take a look at these Citrix alternatives in arbitrary order.

Microsoft Terminal Server

I already just mentioned that mostly every SBC product is easing the Microsoft Implementation as the basis for their product, but offcourse the Terminal Server component only can also be used for your SBC environment. Within Windows 2003 only a Published Desktop can be given to the users. With the new Windows Server version (codename Longhorn) also Published Applications can be created. Also in Longhorn Microsoft will introduce a Web Portal and a SSL secured connection, which are not available right now in Windows 2003. In both versions there is no central management, so settings should be created on every server. Also Load Balancing is based on the Network Load Balancing protocol so this does not reckon on the actually load/usage on the server. Most Client mappings options like printer, audio, clipboard are present. Other features are not available in Microsoft Terminal Server.        

Advantages:

  • Easy installation
  • No additional costs (except the default TS Cal)
  • Suitable for smaller environment where only SBC will be used (using a published desktop)
  • Almost every thin client has the RDP client built-in

Disadvantage:

  • Limited set of features (also in Longhorn)
  • No central management console
  • No Published Applications (limited in Longhorn)
  • Very simple Load Balancing technique

HOBLink Enhanced Terminal Services (ETS)

HOB is one of the earliest manufacturers that entered the SBC market. HOB has several product related to communication to server systems. The first step they made, was adding Terminal Server support in their Java based client. With this client you can also connect to legacy host systems (terminal emulation). Because the client is JAVA based, they support lots of client types like MAC, much UNIX (like) versions, Solaris and Windows.

The real SBC product from HOB is called Enhanced Terminal Services.

From a central console you configure your HOB Farm. You should install the servers manually and also the server should be added manually to the farm. There are not many settings that can be configured within the HOB software it just adds the additional most wanted features.

The configuration is saved on a web server, network share or on a local disk (so no database support).

Load Balancing will be configured per server. HOB has eleven counters that can be used for load balancing. Active sessions, CPU, Memory, Load on NIC, Load on Hard disk are a few examples, all counters can be combined to one load calculation.

HOB enhanced the local drive mapping feature. Within the console you can specify which directories on the disk are not visible, read only or writable.  This feature enhances your security on the local drive mapping.

HOB supports Published Applications and also supports a Published Desktop. With other product/modules the connection can be secured for connection through the internet. The ETS product is not updated with new features for a while, HOB focused on other products like their Blade solution.

Advantages:

  • Many client types support
  • Client can also be used to connect legacy host systems
  • Enhanced Local Drive Mapping features

Disadvantages

  • Difficult to pick the products you need
  • No Full Seamless Support/No Session sharing
  • Relays for maintance and monitoring on default MS Tools

Propalms

The history of Propalms goes just like HOB back to one of the early players on the SBC market. Originally the product was called Canaveral, but was taken over by Tarantella (called Global Desktop at that time). Sun bought Tarantella, but was not interested in the Windows based product. The Widows product was bought by a British supplier and renamed it to Propalms.

The first thing is conspicuous about the product is the special list of prerequisites. For example the default COM+ (Network DTC access) object needs to be changed and the WMI installation provider is needed (for the remote installation). Also a web server is needed because the client will connect via a portal only. A nice feature is that after the initial installation other server can be installed with the software from the initial server.

Propalms uses a website as administration console where all the actions can be performed. If you change something to the configuration a task is created, which is carried out in the background. Users or groups should be added from the Active Directory into the Propalms database to assign settings or applications to those objects. Propalms uses client group for assigning applications, connection settings and/or printers.

Propalms only supports Published Applications. During configuration Propalms uses the start menu to select your application in stead of browsing over the hard disk. There is one load balancer available that apply to all server which can exists of a maximum of six (predefined) resource based counters (no user load counter available). Monitoring the environment is mainly possible from the console, which also have a nice reporting set. Also nice options are the possibility to add a back-up SQL server, which is synchronized by the Propalms software (so no need for a SQL cluster) and the (free) integration of the Uniprint Universal Printer driver.

There are clients available for the Windows, Windows CE, Linux, Mac and some thin client packages. The Windows client installation needs administrative privileges.  Characteristics are the option to add applications to a favorite component, the possibility to take over his active application from other workstations and reconnect to disconnected applications. Also an SSL secured connection possibility is provided by Propalms.

Advantages:

  • Uniprint universal printer product added to the Propalms software (as add-on)
  • Good monitoring and reporting functionality in comparison with the competitors
  • Supported clients and connection option to take over sessions from other client

Disadvantages:

  • Special prerequisite for the COM+ component
  • Way the session is initiated (windowed screen) at the client or the downside effect that Windows logon errors are not displayed
  • Only one load balancer for all servers.

Conclusion

In this first article we started how the SBC technique was developed and how Microsoft was involved. After this introduction we started with describing the Microsoft Terminal Server features and with the first alternatives. In the following articles I will describe more alternatives like Provision Networks VAS, Ericom PowerTerm WebConnect, 2 X Application server and more.

Article previous published at MSTerminalServices.org