OTV Data Traffic

OTV Data Traffic

In this section we will learn how Data traffic (Unicast traffic and Multicast traffic) is delivered over OTV overlay tunnel.

Unicast Traffic:

Let’s suppose that Host A in Site-A wants to talk to Host C in Site 2, and Control Plane MAC reachability information is already communicated and adjacency is from between OTV Sites.

• Host A sends the ethernet Layer-2 packet for destination Host C , This layer 2 frame is local switched and reaches to OTV edge device where it lookup for MAC table and finds that HOST C is reachable on IP-B.
• The Layer-2 Packet is sent to overlay interface where it is encapsulated to IP packet with Source IP is IP address of its Join Interface and Destination IP is IP address of Join interface of Site-2 OTV edge Device which is IP-B.
• Now Layer 3 packet is forwarded to join interface and which is further routed to layer-3 transport infrastructure.
• Site-2 receives the IP packet and Layer -3 packet is decapsulated and then layer-2 Lookup is done for destination MAC address MAC C.
• OTV edge device find the egress interface where MAC C is connected and forwards it to internal interface and finally HOST C receives the data traffic.

Now before going to understand how multicast traffic is sent over Transport lets understand the frame format of OTV.

OTV Frame Format: