What are two reasons to select OTV as the DCI solution to connect multisite topologies? (Choose two.)

Overlay Transport Virtualization (OTV) is a Cisco-proprietary DCI technology designed to extend Layer 2 domains while maintaining network stability and isolation between sites. A key benefit is that it isolates Layer 3 failure domains; issues in the transport network between sites do not affect the Layer 2 environment within a site. Additionally, OTV provides built-in First-Hop Redundancy Protocol (FHRP) localization, which automatically filters protocols like HSRP and VRRP. This prevents them from crossing the DCI link, ensuring each data center maintains its own active default gateway and avoiding potential conflicts or instability.

A. OTV uses a control plane (IS-IS) to reduce unknown unicast flooding, but it does not eliminate all flooding; BUM (Broadcast, Unknown Unicast, Multicast) traffic is still forwarded.
C. OTV is specifically designed to prevent the extension of Spanning Tree Protocol (STP) between data centers by filtering BPDUs, thus isolating STP domains.
D. OTV is a Cisco-proprietary technology. The open-standard alternative for Layer 2 DCI is VXLAN with an EVPN control plane.

1. Cisco, Overlay Transport Virtualization (OTV) Technology Guide, Section: "Failure Isolation," states, "OTV provides a clear demarcation between the remote data centers and the transport network... Failures that occur in the transport network do not impact the data centers."

2. Cisco, Overlay Transport Virtualization (OTV) Technology Guide, Section: "First-Hop Redundancy Protocol Localization," explains, "OTV provides built-in filtering for selected FHRPs... This filtering is enabled by default and does not require any specific configuration."

3. Cisco Press, Data Center Interconnect: Design and Deployment, Chapter 4, "Overlay Transport Virtualization," Section "OTV Benefits," details how OTV provides transport independence, failure isolation, and optimized operations for FHRPs.