System and method for supporting inter-subnet control plane protocol for consistent multicast membership and connectivity in a high performance computing environment

A method for supporting multicast forwarding across multiple subnets in a high performance computing environment, comprising:

• providing, at one or more computers, including one or more microprocessors, a first subnet, the first subnet comprising
• a plurality of switches,
• a plurality of end nodes,
• a subnet manager, and
• an inter-subnet manager;
• configuring a switch port of a first switch of the plurality of switches as a first router port;
• configuring a switch port of a second switch of the plurality of switches as a second router port;
• interconnecting the first subnet with a second subnet via the first router port and the second router port;
• defining a multicast group within the first subnet;
• configuring, by the inter-subnet manager, the first router port to be a full member of the multicast group;
• receiving a multicast packet at the first router port from the second subnet, the received multicast packet belonging to the multicast group;
• and
• wherein, based upon the configuring the first router port as a full member of the multicast group, the multicast packet is prevented from being transmitted to the second subnet once received at the first router port.

A non-transitory computer readable storage medium, including instructions stored thereon for supporting multicast forwarding across multiple subnets in a high performance computing environment, which when read and executed by one or more computers cause the one or more computers to perform steps comprising:

• providing, at one or more computers, including one or more microprocessors, a first subnet, the first subnet comprising
• a plurality of switches,
• a plurality of end nodes,
• a subnet manager, and
• an inter-subnet manager;
• configuring a switch port of a first switch of the plurality of switches as a first router port;
• configuring a switch port of a second switch of the plurality of switches as a second router port;
• interconnecting the first subnet with a second subnet via the first router port and the second router port;
• defining a multicast group within the first subnet;
• configuring, by the inter-subnet manager, the first router port to be a full member of the multicast group;
• receiving a multicast packet at the first router port from the second subnet, the received multicast packet belonging to the multicast group;
• and
• wherein, based upon the configuring the first router port as a full member of the multicast group, the multicast packet is prevented from being transmitted to the second subnet once received at the first router port.