In SAS topology, which device fans out a single SAS link to multiple devices?

• A. Expander
• B. HBA
• C. Disk drive
• D. JBOD

Answer: (A)

In SAS topology, the component that fans out a single SAS link to multiple devices is the expander. An expander sits between the host interface (the HBA) and the multiple disks or enclosures, taking one upstream SAS connection and distributing it across many downstream ports. This lets you attach many drives to a single host link without needing a separate direct connection from the HBA to each drive, enabling scalable growth in storage systems.

The other options don’t provide that fan-out role. The host bus adapter is what the host uses to connect to the SAS network, but it doesn’t multiply a single link into many; a disk drive is the endpoint device, not a routing or splitting device; and JBOD describes a chassis that holds multiple disks, often with its own internal wiring, but by itself it isn’t the device that fans out a single SAS link.