Accessing a WinFrame Server Through LANs and WANs

To attach to a WinFrame server across a LAN or a WAN, WinFrame requires that a network transport (such as IPX/SPX, TCP/IP, or NetBEUI) exist between the ICA client and the WinFrame server.

Once this transport is in place, the ICA protocol builds a list of available WinFrame servers. The ICA client then connects to the server via the transport specified in the ICA client configuration.

The ICA protocol stack is dynamically configured to meet the needs of each transport protocol. For example, the IPX protocol by itself does not guarantee packet delivery, so WinFrame adds a protocol driver to ensure that the data is reliably transmitted between the ICA connection and the host and that it is received by the client. However, because IPX is a frame-based protocol, a frame driver is not included in this particular ICA protocol stack. The Transmission Control Protocol (TCP), however, is a stream protocol; in this case, a frame driver is included. TCP is reliable; therefore, the Reliable protocol driver is not added to the stack. Figure 3-7 illustrates the ICA protocol stack and drivers.

FIGURE 3-7

The ICA protocol stack and drivers

The ICA protocol stack includes the following protocols:

• Compression The Compression protocol can encapsu-late an encrypted ICA packet. This protocol is system replaceable and is not strictly defined in the ICA protocol definition.
  
  
• Encryption The Encryption protocol can encapsulate an encrypted ICA packet. This protocol is system replaceable and is not strictly defined in the ICA protocol definition.
  
  
• Reliable The Reliable protocol is a transmission packaging protocol used to detect transmission errors and to request resends of data. This protocol is used in conjunction with any transport mechanism that does not provide guaranteed delivery. Two such mechanisms are Novell’s IPX protocol and standard asynchronous connections.
  
  
• Framing The Framing protocol is a transmission packaging protocol used to manage stream-oriented communications, such as asynchronous communications and TCP. It is used in conjunction with the Reliable protocol to provide error-free data transmission.
  
  
• Modem Control The Modem Control protocol allows for modem detection and initialization prior to connection.