The exhibit illustrates a Cascaded SRDF topology. In this configuration, data is replicated from a primary site (Site A, R1 device) to a secondary, intermediate site (Site B, R2 device), typically using synchronous replication for zero data loss. The intermediate site then acts as a source, replicating the data onward to a tertiary, remote site (Site C, R11 device), usually with asynchronous replication to accommodate longer distances. This chained, three-site configuration (A→B→C) is the defining characteristic of Cascaded SRDF, providing both local and remote disaster recovery capabilities.

B. SRDF/Star: This topology involves a central primary site replicating data concurrently to multiple, separate secondary sites in a "hub-and-spoke" model, not a chained or sequential one. C. SRDF/Metro: This is an active/active high-availability solution for disaster avoidance over metro distances, where a single virtual volume is presented to hosts from two separate arrays. D. Concurrent SRDF: This configuration allows a single source (R1) device to be the primary for two distinct SRDF pairs, replicating to two different target (R2) devices simultaneously.

1. Dell Technologies PowerMax: SRDF Family Technical Overview (August 2022):

Page 16, Section 3.2.2 "Cascaded SRDF": This section describes and provides a diagram for Cascaded SRDF, stating, "Cascaded SRDF is a three-site disaster recovery solution... The R2 device at the bunker site acts as a synchronous target for the production R1 device and as an asynchronous source device for the remote R2 device." This directly matches the topology shown in the exhibit.

Page 17, Section 3.2.3 "SRDF/Star": Describes SRDF/Star as a "hub and spoke" configuration where a primary site replicates to multiple remote sites.

Page 15, Section 3.2.1 "Concurrent SRDF": Explains that with Concurrent SRDF, "an R1 device can be a source for two separate SRDF pairs."

2. Dell EMC SRDF/Metro Overview and Best Practices Technical White Paper (April 2021):

Page 6, Section "What is SRDF/Metro": Defines SRDF/Metro as an active/active configuration that "allows for host access to the SRDF R1 and R2 devices simultaneously," which is fundamentally different from the A→B→C disaster recovery model shown.