A VxBlock 1000 is running VMware vSphere 6.

In a VxBlock 1000 system running VMware vSphere 6.7, the Fabric Interconnect should be mapped to the access switch in a traditional data center architecture. The Fabric Interconnect is responsible for aggregating traffic from the servers before it is sent to the upstream network, functioning similarly to an access switch which connects end devices to the broader network infrastructure.

References:

Dell EMC VxBlock System architecture guides.

Cisco Unified Computing System (UCS) documentation, as Fabric Interconnects are commonly used in UCS environments.