Cable only Point-to-Point connection Up to 1 Device Direct Routing
Edge Expander Device Set Up to 2 Edge Expanders Up to 128 Devices Table Routing
EDGE EXPANDER
Subtractive Port
Cable only
This is used for point-to-point connections where the initiator controller port connects directly to the target device port. Connectivity is limited to the number of physical ports on the controller. Direct routing allows a device to identify devices directly connected to it.
Edge Expander Device Set
This allows for connectivity with up to 128 SAS devices, allowing the SAS initiator to communicate with these additional devices. Table routing is for identifying devices connected to the expander connected to a device's own PHY, physical interface. Subtractive routing is used when you are not able to find the devices on the edge expander you are connected to. This will pass the request on to the next edge expander you are connected to through the subtractive port.