SDK Resources > Redirection Library > Functionality Overview

Functionality Overview

This section provides an overview of the Redirection Library functionality.

 Note:

   If there is an active redirection session (SOL, Storage Redirection, or KVM), then an Intel AMT power cycle reset or a power off command will be rejected as invalid. See Intel AMT Power State Transitions.

   If power is shut down (e.g., via the operating system) during an active redirection session, it may result in unexpected behavior of the network card ( for example, it may be set to a low link speed).

 

Client Management

The Redirection Library maintains an internal list of managed clients. Clients should be explicitly added to and deleted from the list by using the appropriate API functions. Any operation on a client that does not exist in the list will fail. When adding a new client, the library user must specify the client type: TCP (non-secure client) or TLS (secure client). Once a new client has been added to the library list, its type cannot be changed.

Client Storage

The internal client list maintained by the library can be stored in a file. This allows the library to save information about the clients even after the library (or the application using it) has shut down.

The library’s client storage feature is configurable by the user through the library ini file.  If the client storage feature is disabled, the application using the Redirection Library can still save any desired client information in a storage repository of its choice (for example, in a file or in an external database). When the application restarts at a later time (and initializes the Redirection Library) it can use the repository it chose to restore the client information and add those clients to the library using the library API functions.

SOL

The library allows the user to open an SOL session with a client. Opening a session causes the client to redirect its serial I/O over the wired or wireless LAN. The user can use the library to send keyboard input and receive text output through the SOL protocol, over a TCP connection.

AMT SOL implements a COM port. Sending data over a COM port involves many layers of data transfer complexity, most of which has nothing to do with SOL. OS tools and configurations can change the sent text in many ways, including reformatting Unicode as ASCII, replacing new line characters, and truncating very long lines. This is typically seen when text is moved between different OS types that use different conventions to represent text, but can be also be seen on same-OS configurations. These effects are not related to AMT SOL implementation.

 Note:

The SOL mechanism in Release 6.0 and later releases is somewhat faster than in previous releases. Applications running under the OS (not, for example, the BIOS) that receive traffic sent over SOL may potentially lose data because of buffer overflow. Such applications should enable flow control on the client port associated with the SOL connection. To see which port is used for SOL on a platform running Windows, examine the COM ports in the Device Manager.

To enable flow control, enter the following command in a command window:

Mode COMx DTR=HS   RTS=HS
(where “x” is the identified COM port)

For applications that do not have flow control, or those that run during the period when an OS is loading (for example, Windows BitLocker*) that do not have a flow control option on host side, the console side should manually control the data flow speed. For example, manually type the input instead of pasting a block of text into the console window.

 

Storage Redirection

The Redirection Library allows the user to open a Storage Redirection (USB-R or IDE-R) session with the client, which causes the client to redirect its read & write operations over the wired or wireless LAN.

 Note:

The USB-R protocol replaced the IDE-R protocol in Intel AMT 11.0.

The library implements the USB-R or IDE-R protocol and provides the client with the ability to read and write from a floppy or CD/DVD drive on the Management Console (MC) platform (DVD transfer is supported only on consoles running a version of Windows). The Windows version of the Redirection Library allows the user to specify a CD or DVD image file (*.iso) or a floppy image file (*.img) instead of a physical disk. This functionality is performed automatically by the library, without user intervention. The transferred file can be as large as a DVD or dual-layer DVD image.

If you use an image file, make sure that it is available to the library for the entirety of the Storage Redirection session. If the media containing the image (e.g. a disk-on-key or a CD or DVD containing the file) is removed during the session, unexpected behavior will occur.

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