External SSDs operate via the USB Attached SCSI Protocol (UASP) or over Thunderbolt (TB), typically in an enclosures. Communication is handled by a bridge chip, which can for example bridge SATA/NVMe to USB, or via a hybrid ASIC.
- USB Attached SCSI Protocol (UASP)
- Thunderbolt (TB)
- Bridge Chips
- Hybrid Chips