This MIB module is for configuration & statistic query
of Overlay Transport Virtualization (OTV) functionality on Cisco
routers and switches.
        
Overlay Transport Virtualization is a Cisco's innovative LAN
extension technology.  It is an IP-based functionality that
provides Layer 2 extension capabilities over any transport
infrastructure: Layer 2 based, Layer 3 based, IP switched,
label switched, and so on.  OTV provides an overlay that enables
Layer 2 connectivity between separate Layer 2 domains while
keeping these domains independent and preserving the fault-
isolation, resiliency, and load-balancing benefits of an IP-
based interconnection.
        
OTV introduces the concept of MAC routing, which means a
control plane protocol is used to exchange MAC reachability
information between network devices providing LAN extension
functionality. This is a significant shift from Layer 2
switching that traditionally leverages data plane
learning, and it is justified by the need to limit flooding of
Layer 2 traffic across the transport infrastructure.
        
OTV also introduces the concept of dynamic encapsulation for
Layer 2 flows that need to be sent to remote locations.
Each Ethernet frame is individually encapsulated into an IP
packet and delivered across the transport network.
        
Finally, OTV provides a native built-in multi-homing capability
with automatic detection, critical to increasing high
availability of the overall solution. Two or more devices can be
leveraged in each data center to provide LAN extension
functionality without running the risk of creating an end-to-end
loop that would jeopardize the overall stability of the design.
        
The followings detail the OTV specific terminology:
        
Edge Device
        
The edge device performs OTV functions: it receives the Layer
2 traffic for all VLANs that need to be extended to remote
locations and dynamically encapsulates the Ethernet frames
into IP packets that are then sent across the transport
infrastructure.
        
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.
        
Join Interface
        
The Join interface is used to source the OTV encapsulated
traffic and send it to the Layer 3 domain of the data center
network.
        
Overlay Interface
        
The Overlay interface is a logical multi-access and multicast-
capable interface that must be explicitly defined by the user
and where the entire OTV configuration is applied.
        
The following terms are used throughout this MIB:
        
AED     Authoritative Edge Device
        
ARP     Address Resolution Protocol
        
DNS     Domain Name System
        
ISIS    Intermediate System to Intermediate System Routing
        Protocol 
        
LSPDB   Link State PDU Database
        
OTV     Overlay Transport Virtualization
        
VLAN    Virtual Local Area Network
        
VPN     Virtual Private Network