Which technology prevents the flooding of unknown unicast traffic across an IP link between two data centers?

OTV specifically addresses Layer 2 extension across IP networks by encapsulating Layer 2 frames in IP packets and maintaining a MAC address table. This allows OTV to learn MAC addresses and avoid flooding unknown unicast, broadcast, and multicast traffic beyond the local data center or to remote sites where the MAC is known, thereby optimizing bandwidth and preventing loops.

VPLS (Virtual Private LAN Service) provides multipoint-to-multipoint Layer 2 VPNs over an MPLS network, but it can still flood unknown unicast traffic to all participating Provider Edges (PEs) until MAC addresses are learned.

MPLS (Multiprotocol Label Switching) is a forwarding mechanism that uses labels to route packets efficiently, primarily at Layer 2.5/3, but it does not inherently prevent Layer 2 unknown unicast flooding across extended Layer 2 links.

TRILL (Transparent Interconnection of Lots of Links) is a Layer 2 technology that uses IS-IS routing within a single data center to replace Spanning Tree Protocol, but it does not address unknown unicast flooding across inter-data center IP links.