System and method for on-demand unicast forwarding in a high performance computing environment

A method for on-demand unicast forwarding in a high performance computing, comprising:

• providing, at a computer, the computer comprising one or more microprocessors,
• a plurality of switches;
• a plurality of host channel adapters;
• and
• a plurality of hosts;
• providing, at two rails, redundant connectivity between the plurality of hosts, wherein each rail comprises a set of the plurality of switches;
• detecting a disruption i connectivity between two hosts of the plurality of hosts;
• re-establishing communication between the two hosts of the plurality of hosts via unicast packets on an inter-rail link, the inter-rail link being provided between the two rails.

A non-transitory computer readable storage medium having instructions for on-demand unicast forwarding in a high performance computing, which when read and executed cause a computer to perform steps comprising:

• providing, at a computer, the computer comprising one or more microprocessors,
• a plurality of switches;
• a plurality of host channel adapters;
• and
• a plurality of hosts;
• providing, at two rails, redundant connectivity between the plurality of hosts, wherein each rail comprises a set of the plurality of switches;
• detecting a disruption i connectivity between two hosts of the plurality of hosts;
• re-establishing communication between the two hosts of the plurality of hosts via unicast packets on an inter-rail link, the inter-rail link being provided between the two rails.