I'am familiar with Infiniband, GPFS and RDMA is a single switch environment. This is straightforward and you can define your IPoIB interfaces as bond to fail over when individual links fail. I have also seen configurations where two IB switches are used and bonding to fail over between the two, but in a active/passive arrangement. In both cases the resulting configuration is similar to an analogue Ethernet configuration.
I'm looking for a configuration similar to two Ethernet switches, stacked together, with the hosts using LACP to manage the links. This allows to use the full bandwidth of the links (link aggregation) and provides fail-over in case of switch failure.