
• Someone has to setup the forwarding tables and
give every port an LID
– “Subnet Manager” does this work
• Different routing algorithms give different paths
CCGrid '11
IB Switching/Routing: An Example
Leaf Blocks
Spine Blocks
P1P2
DLID Out-Port
2 1
4 4
Forwarding Table
LID: 2
LID: 4
1
2
3
4
59
An Example IB Switch Block Diagram (Mellanox 144-Port)
Switching: IB supports
Virtual Cut Through (VCT)
Routing: Unspecified by IB SPEC
Up*/Down*, Shift are popular
routing engines supported by OFED
• Fat-Tree is a popular
topology for IB Cluster
– Different over-subscription
ratio may be used
• Other topologies are also
being used
– 3D Torus (Sandia Red Sky)
and SGI Altix (Hypercube)
Komentarze do niniejszej Instrukcji