A data center with over 4000 VLANs must be stretched to a disaster recovery site. The solution must support the migration of virtual machines to a disaster recovery site. To support the scalability of

LISP is primarily a host mobility and network virtualization technology, not the primary DCI solution for stretching entire VXLAN fabrics with BUM replication requirements.

VXLAN Multi-Site extends VXLAN EVPN fabrics across multiple data centers, offering excellent scalability for thousands of VLANs (VNIs) and supporting VM mobility. This solution also inherently supports head-end replication for broadcast, unknown unicast, and multicast (BUM) traffic, which aligns with the specified requirement for efficient DCI.

OTV (Overlay Transport Virtualization) is a DCI technology for Layer 2 stretching but has scalability limitations for thousands of VLANs and uses multicast for BUM traffic, conflicting with the head-end replication requirement.

MPLS over GRE is a generic tunneling approach that does not inherently provide the advanced Layer 2 stretching, scalability, or efficient BUM replication mechanisms required for VXLAN fabrics across data centers.