Dedicated Citrix ICA Master Browser

Dedicated Citrix ICA Master Browser

Advantages and Setup

By Elvin Sosa

Citrix Systems, Inc

Notice
The information in this publication is subject to change without notice.
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Copyright © 2000 Citrix Systems, Inc., 6400 NW 6th Way, Ft. Lauderdale, Florida 33309 U.S.A. All rights reserved.
Version History
February 9, 2000 / Elvin Sosa / Version 1.0
February 29, 2000 / Elvin Sosa / Version 1.1

TABLE OF CONTENTS

Overview

Advantages of the dedicated Master ICA Browser

Isolated Critical Functionality

Isolated Master Browser Processing

Faster Connection Times and Directed Client Requests

Lower Rate of Random Browser Elections

Increased License Availability

Increased License Manageability

Increased Cross-Subnet License Availability

Turnkey backup Master ICA Browser

Dedicated Master ICA Browser Set-Up

Requirements

Licensing your ICA Master Browser

Standard Licensing Plans

Volume Purchase Licensing Agreements

Considerations

Configuration

Creating a dedicated WinFrame 1.7 Master ICA Browser

Creating a dedicated WinFrame 1.8 Master ICA Browser

Creating a dedicated MetaFrame 1.0 Master ICA Browser

Creating a dedicated MetaFrame 1.8 Master ICA Browser

Advantages of creating a dedicated Backup ICA Browser

Lower the Rate of Random Browser Elections

Increased License Availability

Backup ICA Browser Set-Up

Requirements

Considerations

Configuration

Creating a WinFrame 1.8 or MetaFrame 1.8 Backup ICA Browser

1

Dedicated Citrix ICA Master Browser

Overview

This white paper provides guidelines to help you optimize a Citrix implementation by deploying a dedicated Master ICA Browser. It also discusses how setting a Backup ICA Browser and/or a backup Master ICA Browser can help you manage your Citrix Implementation throughout the Enterprise.

Advantages of the dedicated Master ICA Browser

Isolated Critical Functionality

Use of dedicated Master Browsers provides for increased stability, when compared to the use of production Citrix servers as a Master Browser, because their only function is to house the Master ICA database. When the Master Browser is also a production application server, it must share resources with applications that may have adverse effects on a servers’ available memory, CPU usage, bandwidth utilization, etc. This type of scenario can occur for many reasons – poorly written custom applications, applications with memory leaks, improperly tuned applications, high resource usage or spike resource usage applications, etc.

It is therefore logical to separate the Master Browser function from the Application server , thus ensuring that this critical function of your ICA network is unhampered by contact with unpredictable or unsupported applications.

Isolated Master Browser Processing

In keeping with the separation of critical functionality from a resource intensive environment, in large networks with servers that are providing applications to a large numbers of users simultaneously, it is also advisable to separate Master ICA Browser functionality to a dedicated server.

When users connect to a Citrix server or published application, they first request the availability of servers, applications, licenses, and load balanced application availability, from the Master Browser. In typical Citrix implementations, with many servers where many users are requesting connections at the same time, this type of activity can severely limit a servers’ ability to effectively process existing connections. By separating the Master ICA Browser from the application server, you can ensure that your applications and user sessions will be processed more efficiently.

Faster Connection Times and Directed Client Requests

If you have a dedicated Master ICA Browser you can assign a static IP address to this machine and pre-configure Citrix clients to request information directly from the Master Browser. By default, Citrix clients broadcast a request to all MetaFrame servers on the local subnet asking for the Master Browser. The replying server sends the name of the Master Browser, and the client directly contacts the named server for connection information. When connecting from a different subnet, the client's Server Location setting must be used to direct users to the Master ICA Browser, if there is no ICA Gateway present.

By creating a dedicated Master Browser with a static IP address, you can create a pre-configured client that would allow you to direct all connection requests to your Master ICA Browser. You can use the IP address or DNS name of the Master ICA Browser to configure this in the Server Location utility on the client side. This client can thereafter be deployed using the Auto Client Update Utility, or a modified set of installation disks. Connections initialize faster by directing the client to the Master ICA Browser.

Additionally, you may want to use DNS names for 'Server Locations' where possible. Since DNS gives you the flexibility of centrally managing the actual IP addresses of your ICA servers, it is much better to deploy the clients with the Server Location using DNS names. DNS is cross platform, so even most Windows Based Terminals can get DNS name resolution. This enables you to maintain/manage those entries in a single location for all client types. This does create a dependency on DNS name resolution, so consider the pros and cons before implementing this as a part of your solution.

Lower Rate of Random Browser Elections

The ICA Browser service forces an election under the following conditions:

• Current Master Browser does not respond to another ICA Browser
• Current Master Browser does not respond to an ICA client
• New Citrix Server is added
• Two Master Browsers are detected on the same subnet

When an election takes place, the ICA Browser database needs to be recreated through network broadcasts on the newly elected Master. With large numbers of servers, these requests and broadcasts can degrade network performance temporarily. By implementing a dedicated Master ICA Browser and Backups, you ensure a higher rate of response to client requests and to other ICA Browsers, effectively decreasing the number of elections that are likely to take place on your network.

Increased License Availability

By default, a Master ICA Browser that is MetaFrame version 1.8 and above, stores license information for 48 hours after a licensed machine has been removed from your network. This means that if a server goes down, or if you remove a server from your network, the licenses that were pooled from that server are still available for client connections for the next 48 hours. This facility allows you sufficient time to replace the machine with a respective license.

However, if a browser election takes place and there is no Backup ICA Browser (MetaFrame and WinFrame 1.8 and above), the ICA database needs to be rebuilt from scratch. If this happens within the 48-hour period, the pooled licenses are no longer available. Since creating a dedicated Master ICA Browser is more dependable and decreases the number of elections that are likely to take place on your network, you decrease the chances of the ICA database being recreated and losing any pooled licenses whose donating servers are no longer available.

Increased License Manageability

By creating a dedicated Master ICA Browser, your implementation will open itself to a dedicated License server as well. Now, you can install all user bump packs onto the Master ICA Browser, pool them from there and manage all licenses from that server. If a MetaFrame machine goes down in your network, you will not have to reinstall bump packs on that machine. The only things you will have to install are the Citrix Base License and any Management Services licenses such as Load Balancing, Secure ICA, and RMS. If this machine is out of commission for more than 48 hours, you still have access to all of the pooled licenses from the bump packs. Without this, after the 48-hour license retention limit, you would lose not only the pooled base license, but also any bump pack licenses. In this way, you can limit your losses.

Increased Cross-Subnet License Availability

With the introduction of MetaFrame 1.8a for Microsoft Windows NT 2000, Citrix has introduced Dual Subnet License Pooling. Dual Subnet License Pooling is poised to play an integral role in the Business and Disaster Recovery of applications deployed with Citrix.

This solution entails creating 2 Dedicated ICA Master Browsers, one at each site, with a two-way gateway across the two subnets. Install 50% of licenses on each subnet. The result is a stable, centrally manageable, enterprise class solution for the Citrix implementation.

Turnkey backup Master ICA Browser

It is possible to configure a clone machine to take over as the Master Browser should your dedicated machine fail. You don’t need to take the time to troubleshoot problems on your Master ICA Browser. Just turn on the cloned machine, and it will assume its new role. It would act in the same capacity as the dedicated machine, and you would effectively have a business recovery solution for your Master ICA Browser.

Whenever a change is made or licenses added to the Master ICA Browser, make sure that you create a drive image or backup of the new configuration. In the event of a drive or machine failure, replace the failed device with your backup. In this way, your implementation can approach a 100% availability threshold.

Dedicated Master ICA Browser Set-Up

Requirements

• Microsoft Windows NT 2000 with Terminal Services
• Citrix MetaFrame 1.8a
• Supported MetaFrame license from “Licensing your ICA Master Browser” section
• 200 Mhz and above Pentium Class Machine (Single Processor)
• 128 MB RAM
• Minimum 10 Mb Ethernet Card

-OR-

• Microsoft Windows NT 4.0 Terminal Server Edition
• Citrix MetaFrame 1.0 or above
• Supported MetaFrame license from “Licensing your ICA Master Browser” section
• 200 Mhz and above Pentium Class Machine (Single Processor)
• 64 MB RAM
• Minimum 10 Mb Ethernet Card

-OR-

• Citrix WinFrame 1.7 or above
• Supported WinFrame license from “Licensing your ICA Master Browser” section
• 200 Mhz and above Pentium Class Machine (Single Processor)
• 64 MB RAM Minimum
• Minimum 10 Mb Ethernet Card

Note

Many present implementations of Dedicated Master ICA Browsers use a Pentium-class fat client which can be replaced by a thin client. The main guideline is to implement a machine that satisfies your performance requirements. However, you should not need a machine more powerful than the recommended machine configurations described above.

Licensing your ICA Master Browser

Standard Licensing Plans

In order for your dedicated ICA Master Browser to work, it must be licensed properly. If a dedicated ICA Master Browser does not have an activated server license, it will cease to function after 35 days. Also, whenever implementing a solution like this, it is important to remain compliant with Citrix Licensing policies. Supported licensing methods for the ICA Master Browser are as follows:

License Type / Limitations
WinFrame or MetaFrame Base License (15 user included) / None
WinFrame or MetaFrame for Terminals License / Clients, including the administrator, can only connect with a Citrix Client Terminal License.
WinFrame or MetaFrame for Workgroups (5 user included) / Cannot pool licenses. Does not allow addition of User Bump Packs or Load Management Services Option Pack.

From the preceding license group, the WinFrame or MetaFrame for Terminals License is the most cost effective way to license your Dedicated ICA Master Browser. This license also serves as a way to control access to your ICA Master Browser. Each user that accesses a server licensed in this manner requires a client side Citrix Terminal License. Only users with this Client side Terminal License can connect to your Dedicated ICA Master Browser. This effectively reduces the number of administrators that can connect to your server and acts as another layer of security for server access.

The Citrix for Terminals License and the Standard WinFrame or MetaFrame Base License are the only two licenses that allow you to manage user bump packs from one server. With these two licenses, you will add user bump packs only on your Dedicated ICA Master Browser and then pool those licenses for use on your local subnet. Please see the section titled “Advantages of Creating a Dedicated ICA Master Browser - Increased License Manageability” for more information on license manageability.

Furthermore, MetaFrame 1.8a for Microsoft Windows 2000 allows dual-subnet license pooling. This allows you to control more of your user licenses from a single server. Please see the section titled “Advantages of Creating a Dedicated ICA Master Browser – Increase Cross-Subnet License Availability” for more information.

Volume Purchase Licensing Agreements

The following license programs contain unlimited user base licenses. Licenses are audited every month and either leased or purchased. If purchased, monthly audits are performed in which the difference between owned license usage and actual license usage is computed. The result is the number of licenses used, but not purchased. Customers then purchase these licenses in order to remain in compliance with Citrix Licensing. The Corporate Licensing Plan and the Enterprise License Agreement require that a specific volume purchase be met in order to both join these plans and receive the discounts provided by them. For more information on the CLP, ELA, and ASP license plans, please visit our website.

Corporations, Enterprises, and the ASP’s are ideal candidates for ICA Master Browsers and the licensing plans noted below are well suited to accept this type of design. However, all servers must be included in the same licensing model in order for your setup to work properly. You should not have a mixed environment that contains both standard and volume purchase license types as this will have unpredictable results.

License Plans / Description
Corporate Licensing Plan / This licensing plan provides a discount for Corporate volume user license orders. Each server has a zero user license and the number of licenses purchased is determined every month by Citrix. This is a pay as you go license purchasing program.
Enterprise Licensing Plan / This licensing plan provides a discount for Enterprise volume user license orders. Each server has a zero user license and the number of licenses to be purchased is determined every month through Citrix. This is a pay as you go license purchasing program.
Level E Program / This licensing plan provides a discount for Educational volume user license orders. Each server has a zero user license and the number of licenses to be purchased is determined every month through Citrix. This is a pay as you go license purchasing program.
ASP Licensee / License Program specific for certified Citrix Application Service Providers. Each server has a zero user license and licenses are leased on an average usage per month basis.

For pricing information, please refer to our website at

Considerations

As a general rule of thumb, the highest common denominator of Citrix WinFrame or MetaFrame should be implemented as the Master ICA Browser. By default, the Citrix MetaFrame or WinFrame server with the newest version of the ICA Browser will become the Master ICA Browser. This also includes any machine that has had a hotfix (which includes a newer ICA Browser than any version currently installed on another Citrix Server) installed. This means that if you have a mixed Citrix environment, you have no choice but to implement the newest version of MetaFrame or WinFrame as the Master ICA Browser. Furthermore, if you plan on implementing a solution that includes Backup ICA Browsers, your Master ICA Browsers should be Citrix MetaFrame or WinFrame version 1.8 and above.

When implementing a solution of this kind, it is imperative that all machines be kept at the same service pack and hotfix level. This ensures proper communication between servers. When updating servers with new hotfixes, install on the Master ICA Browser first. This will provide a production test bed as well as allow you to quickly recover from hotfixes that have adverse effects on your particular network. You should also implement a quick recovery backup solution for the Master ICA Browser.

Using a dedicated Master ICA Browser is recommended for implementations as small as 2 or 3 Citrix servers. It is recommended that you test this type of network topology to determine whether it adds value to your specific implementation. You will find, however, that adopting the idea of a dedicated Master ICA Browser per network subnet will make your Citrix Solution even more scalable, stable, and manageable.