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Data collectors

Data collectors in MetaFrame XP are analogous to an ICA master browser. Each zone contains one MetaFrame XP server that is configured as the data collector. The data collector receives information from each of the other XP servers in the zone. Like the master browser in previous versions, the data collector maintains a list of all servers and the applications they serve, along with the TCP/IP addresses of each server. Data collectors are chosen via elections much like NT domain controllers and MetaFrame 1.x ICA master browsers.

Data store

The data store is another critical component that must be properly planned. Available in several different flavors, the data store allows administrators to customize their environment to meet the business needs. Based upon ODBC compliant database engines, MetaFrame XP currently supports three database formats and two connection methodologies.

Diffie-Hellman key algorithm

The Diffie-Hellman key agreement algorithm was designed to allow to computers to exchange information that would allow both computers to arrive at the same exact symmetric key with out ever transmitting data in the communication that would compromise the symmetric key used in that session.

Diffie-Hellman parameters

These are used during key negotiation. When a secure ICA client establishes an encrypted session, the MetaFrame server and client use a public key algorithm to pass public keys and these parameters over the communication path. Using these parameters, the client and server's Private Keys and Public keys both the client and the server arrive at the same unique Symmetric Key.

Digital Independence

This is the marketing term Citrix uses to describe the concept of being able to run any application, on any device, over any network connection, wireless to Web. Attaining Digital Independence means being freed from the traditional restrictions and intricacies of technology so everything can compute.

Digital Subscriber Line (DSL)

There are many variants of digital subscriber line (xDSL). All versions utilize the existing copper loop between a home and the local telco's Central Office (CO). Doing so allows them to be deployed rapidly and inexpensively. However, all DSL variants suffer from attenuation, and speeds drop as the loop length increases. Asymmetrical DSL (ADSL) and Symmetrical DSL (SDSL) may be deployed only within 17,500 feet of a CO, and Integrated Services Digital Network emulation over DSL (IDSL) will work only up to 30,500 feet. All DSL variants use Asynchronous Transfer Mode (ATM) as the data-link layer.

Direct Memory Access (DMA)

These channels are rare these days, but you may see them used by audio devices. As you might recall, DMAs have the ability to move data from the device to RAM without involving the processor.

Direct mode

Direct mode allows servers to communicate directly with the data store database to maximize performance, however this requires more sophisticated database engines such as MS SQL or Oracle.

Disconnect

Allows the administrator to disconnect a user from their current session. The session remains open on the server, and the user is able to reconnect to the disconnected session the next time they log on, provided that the server has not been rebooted.

Disk caching/compression

This allows the Win32 client to work well over low speed links, whether they are asynchronous or WAN links. The amount of drive space given over to caching can be modified (the default is one percent), the cache directory can be chosen, and the minimum size bitmap to be cached can be configured.

Disk data I/O

Monitors disk I/O per second in kilobytes. This rule by default will report full load when the total disk I/O in kilobytes per second is greater than 32,767 and will report no load when the disk I/O in kilobytes per second is equal to zero.

DNS:

See Domain Name System

Domain Name System (DNS)

Because the actual unique Internet Protocol (IP) address of a web server is in the form of a number difficult for humans to work with, text labels separated by dots (domain names) are used instead. DNS is responsible for mapping these domain names to the actual IP numbers in a process called resolution. Sometimes called a Domain Name Server.

Driver

This field associates a server side driver with the client printer. This driver name can be entered manually, or you can select from one of two menus.

DSL:

See Digital Subscriber Line



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CCA Citrix MetaFrame XP for Windows Administrator Study Guide Exam 70-220
CCA Citrix MetaFrame XP for Windows Administrator Study Guide (Exam 70-220)
ISBN: 0072193190
EAN: 2147483647
Year: 2001
Pages: 169

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