Which OTV failure isolation feature maps a MAC address from a remote data center to that remote data center’s join interface IP address?
- unknown unicast handling
- broadcast policy control
- ARP optimization
- STP isolation
Overlay Transport Virtualization (OTV)’s unknown unicast handling feature maps a Media Access Control (MAC) address from a remote data center to that data center’s join interface Internet Protocol (IP) address. The join interface is the Open Systems Interconnection (OSI) networking model Layer 3 interface on which OTV is deployed and that is capable of discovering other OTV-enabled data centers. OTV’s unicast traffic handling feature advertises MAC addresses between data centers. Because of this, advertisement and mapping process, OTV is capable of suppressing the transmission of unknown unicast traffic across data centers.
OTV is a technology that extends Layer 2 networks across data centers. Similar to Ethernet over Multiprotocol Label Switching (EoMPLS), virtual private LAN services (VPLS), and dark fiber, OTV is intended to enable the extension of Layer 2 applications across large geographic distances. It is typically deployed on data center edge devices. OTV uses MAC address routing to ensure that Layer 2 reachability information can be transmitted between data centers. Unlike other Layer 2 extension technologies, OTV’s MAC address routing takes place at the control plane level. Other technologies rely on data plane forwarding and flooding.
OTV’s Spanning Tree Protocol (STP) isolation feature ensures that bridge protocol data units (BPDUs) are not forwarded across the overlay. This feature is enabled by default. Because BPDUs are suppressed, each data center’s STP domain remains independent of other data centers connected to the overlay. This prevents data centers from accidentally creating Layer 2 loops over OTV.
Broadcast policy control and Address Resolution Protocol (ARP) optimization are OTV features that reduce traffic between OTV-connected data centers. Each of these features reduces the amount of broadcast traffic that is flooded between data centers.