Attention: The Supervisor Fallback Mode is an experimental feature and only available for testing purpose.

Introduction

The Supervisor Fallback Mode is responsible to force the network into the state "NotAvailable.Fallback". This is a special network state which is supported by OS8121x INIC derivatives. It allows to establish network streams although the network state "Available" cannot be reached. This might be caused by a device or cable defect. Based on the local INIC the network can run in "Fallback Mode" by excluding the defective sections. There are certain restrictions when running the network in "Fallback Mode":

Application communication between different nodes are not possible.
The order of devices within the network is evident. It is only possible to stream in one direction. The order is reverse the usual order in network "Available.Regular" state.
If a stream can be established successfully depends on the position of the network defect.

INIC Configuration

It is required to define a certain fallback role for each network node. In addition it is required to define within the INIC Configuration String the resources which must be built automatically when entering the network state "NotAvailable.Fallback".

See also INIC API User's Guide, section Configuration String.

Definition of Routes

It is required to specify separate route structures for the UNICENS Management Library that will be loaded only when entering the network state "NotAvailable.Fallback". These route is required only when resources must be built on the local node which cannot be define within the INIC Configuration String.

See also Getting Started, section Static Connections.

Execution of Fallback Mode

The application may enter the Supervisor Fallback Mode by calling Ucs_Supv_SetMode() or by setting the Supervisor Fallback Mode as initial Supervisor Mode within the initialization structure. As soon as the Network Supervisor enters the network state "NotAvailable.Fallback" the Routing Management automatically starts to build the local resources of all active and fallback_enabled routes.

Leaving the Supervisor Fallback Mode

It is possible to return from Supervisor Fallback Mode to Supervisor Inactive Mode by calling Ucs_Supv_SetMode(). After successful execution the application may enter other Supervisor Modes. However, the application must consider once having entered the Supervisor Fallback Mode, the network nodes configured as Fallback Guard may remain active in the reverse direction. It is required to reset these network nodes before it is possible to startup the network in a regular way. The application shall consider this to be done by the network power management.