User`s guide

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1: Introducing the L1 and L2 Controllers

The following are functions performed by the L2 controller. (For a list of functions

speciﬁc to a product or component, see your server or graphics system user’s guide.)

• Controls resource sharing.

• Controls the L1 controllers on the server or graphics system.

• Maintains controller conﬁguration and topology information between the L1 and

hardware L2 controllers.

• Routes data between upstream devices and downstream devices.

Upstream devices provide control for the system, initiate commands for the

downstream devices, and act on the messages that they receive from downstream

devices.

Downstream devices perform the actions that are speciﬁed by the L2 controller

commands, send responses to the L2 controller that indicate the status of the

commands, and send error messages to the L2 controller.

• Allows remote maintenance via a modem.

• Enables the entering of commands to toggle between L2, L1, and the console mode.

This means you can power on your server with L1 or L2 controller commands, and

monitor the power-on activity by changing to the console mode.

In a system with more than one hardware L2 controller, all hardware L2 controllers are

peers and each propagates conﬁguration information to the other L2 controllers. Each L2

controller monitors its associated L1 controllers and propagates this information to the

other L2 controllers.

Note: For more details about the L2 controller hardware and using the L2 controller

touch display to perform server functions such as powering on and powering off the

server or graphics system, see your user’s guide.