This section, which explores the inner workings of a MetaFrame XP server farm operating in native mode, is considerably shorter than the previous section covering mixed mode. This is because native mode acts as MetaFrame XP was designed. Basically the remainder of this book deals with native mode. However, there are some technical aspects to be aware of when native mode MetaFrame XP servers are operating in environments that also contain MetaFrame 1.8 servers.
Native mode is the default configuration for MetaFrame XP server farms. In native mode, MetaFrame XP server farms do not run any of the MetaFrame 1.8 legacy services, such as the ICA browser. In native mode:
- No communication is conducted between the MetaFrame XP and the MetaFrame 1.8 servers.
- The ICA browser and Program Neighborhood services are not used in the MetaFrame XP server farm.
- MetaFrame XP licenses are not pooled with MetaFrame 1.8 licenses.
- Published applications cannot be load balanced across MetaFrame 1.8 and MetaFrame XP servers.
Client Communication with Native XP and 1.8 Farms
For the most part, MetaFrame XP servers operating in native mode will work in the exact same manner regardless of whether or not any MetaFrame 1.8 servers are present. There is only one small difference that you should be aware of.
MetaFrame XP servers operating in native mode will detect if there are any MetaFrame 1.8 servers on the same subnet as any XP servers in the farm. If there are, then the MetaFrame XP servers will not respond to ICA client broadcasts (when clients are trying to "auto-locate" MetaFrame servers). If the MetaFrame XP servers do not detect any MetaFrame 1.8 servers, then the XP servers will respond to ICA client broadcast requests. This behavior is so that native mode MetaFrame XP servers do not intercept client "auto-locate" broadcasts that are meant for MetaFrame 1.8 servers. (After all, new ICA clients that are looking for MetaFrame XP servers do not use the "auto-locate" broadcast behavior anymore.)
This default behavior of MetaFrame XP can be changed. In the MetaFrame settings of the farm (CMC | Farm Properties | MetaFrame Settings Tab | Broadcast Response), you can configure the zone data collectors or the RAS servers to respond to ICA client broadcasts. If you had a mixed mode farm that you have since migrated to a native XP farm after eliminating all of your MetaFrame 1.8 servers, you will need to manually configure your XP farm servers to respond to ICA client broadcasts.
On subnets with MetaFrame XP servers in native mode and unrelated MetaFrame 1.8 servers:
- ICA clients that find MetaFrame servers via the "auto-locate" method will get a server list of only MetaFrame 1.8 servers. This occurs because the XP servers will not respond to the client's "auto-locate" UDP broadcast, and the 1.8 servers do not know anything about the XP servers since the XP servers are in native mode and not running the ICA browser.
- If an ICA client is configured to "auto-locate" a server via the TCP/IP+HTTP protocol, whichever MetaFrame server is configured for the "ica" DNS hostname will determine the platform of the servers that are returned to the client.
- To view MetaFrame XP servers, ICA clients must specify the address of an XP server in the "Default Server Location" field. When this occurs, only MetaFrame XP servers are listed.
- If the ICA client's "Default Server Location" list is made up of both MetaFrame 1.8 and XP servers, whichever platform responds first will determine the resources that are shown to the client.
As you can see, in native mode there is no communication between the MetaFrame XP and the MetaFrame 1.8 servers. If you have both of these servers on the same subnet with your MetaFrame XP servers operating in native mode, you can avoid this potential confusion by doing one of the following:
- Set your MetaFrame XP server farm to mixed mode.
- Put the MetaFrame XP and MetaFrame 1.8 servers on separate subnets.
- Ensure that ICA clients are explicitly pointed towards the correct servers.
On subnets with only MetaFrame XP servers that are part of a farm running in native mode:
- By default, ICA clients using the "auto-locate" discovery method will not find anything, because the XP servers do not respond to the clients' auto locate UDP broadcast, and that broadcast will not travel across subnets to find other MetaFrame 1.8 servers.
- You can configure the XP servers to respond to ICA clients' UDP broadcast requests through the CMC (as outlined previously).
- If the servers are not configured to respond to UDP requests, the "default server location" must be configured to connect to MetaFrame XP servers.
- The DNS hostname "ica" can be used to point to a MetaFrame XP server that will be discovered via "auto-locate" if the ICA client uses the TCP/IP+HTTP protocol.