Combining separate infiniband subnets into virtual subnets

A method of connecting a first Infiniband subnet to a second Infiniband subnet, wherein the method comprises configuring a router for:

• receiving globally-routed packets from the first Infiniband subnet;
• processing the globally-routed packets to provide local route headers suitable for the second Infiniband subnet;
• receiving locally-routed packets from the first Infiniband subnet that are directed to an end node in the second Infiniband subnet;
• and
• delivering the locally-routed packets to the second Infiniband subnet.

A method of connecting a first Infiniband subnet to a second Infiniband subnet, wherein the method comprises:

• receiving locally-routed packets from the first Infiniband subnet that are directed to an end node in the second Infiniband subnet;
• encapsulating the locally-routed packets in raw datagrams;
• communicating the raw datagrams across a third Infiniband subnet;
• de-encapsulating the locally-routed packets;
• and
• providing the locally-routed packets to the second Infiniband subnet.

A router that comprises:

• multiple port interface circuits coupled to corresponding Infiniband subnets;
• and
• an internal Infiniband subnet that couples the multiple port interface circuits together,
• wherein a first port interface circuit is configured to receive locally-routed packets from a first Infiniband subnet that are directed to an end node in a second Infiniband subnet,
• wherein the first port interface circuit is configured to encapsulate the locally-routed packets in raw datagrams that the internal Infiniband subnet transports to a second port interface circuit, and
• wherein the second port interface circuit is configured to de-encapsulate the locally-routed packets and provide them to the second Infiniband subnet.