Which two technologies that can be used to connect data centers over an IP network and provide layer 2 LAN extension?

A.
IS-IS

B.
VXLAN

C.
TRILL

D.
Fabric Path

E.
OTV

Explanation:
Virtual Extensible LAN (VXLAN) is a proposed encapsulation protocol for running an overlay network on existing Layer 3 infrastructure. An overlay network is a
virtual network that is built on top of existing network Layer 2 and Layer 3 technologies to support elastic compute architectures.
Internal Interfaces:
To perform OTV functionality, the edge device must receive the Layer 2 traffic for all VLANs that need to be extended to remote locations. The Layer 2 interfaces,
where the Layer 2 traffic is usually received, are named internal interfaces

internal interfaces are regular Layer 2 interfaces configured as access or trunk ports. Trunk configuration is typical given the need to concurrently extend more than
one VLAN across the overlay. There is no need to apply OTV-specific configuration to these interfaces. Also, typical Layer 2 functions (like local switching,
spanning-tree operation, data plane learning, and flooding) are performed on the internal interfaces. Figure 1-2 shows Layer 2 trunks that are considered internal
interfaces which are usually deployed between the edge devices also.
Overlay Transport Virtualization (OTV) on the Nexus 7000 is an industry-first technology that significantly simplifies extending Layer 2 applications across distributed
data centers. You can now deploy Data Center Interconnect (DCI) between sites without changing or reconfiguring your existing network design.
https://www.cisco.com/c/en/us/td/docs/solutions/Enterprise/Data_Center/DCI/whitepaper/DCI3_OTV_Intro/DCI_1.html