H3C Technologies H3C S12500-X Series Switches - Manual (Page 13)

6
• Multicast mode—Also called tandem replication. The source VTEP sends the flood frame in a
multicast VXLAN packet destined for a multicast group address. Transport network devices replicate
and forward the packet to remote VTEPs based on their multicast forwarding entries. See
Figure 6 .
Each destination VTEP floods the inner Ethernet frame to all the site-facing interfaces in the VXLAN. To
avoid loops, the destination VTEPs do not flood the frame to VXLAN tunnels.
Figure 5 Unicast mode
Figure 6 Multicast mode
VTEP 1 VTEP 2
Transport network
P
Server 1
VM 1
VM 2
VM 3
Server 3
VM 7
VM 8
VM 9
Server 2
VM 4
VM 5
VM 6
FGE1/0/1
FGE1/0/2
FGE1/0/1
VX
LA
N tu
nne
l
VTEP 3
VXLAN tunnel
Server 4
VM 10
VM 11
VM 12
Replicate and
encapsulate
VTEP 1 VTEP 2
Transport network
P
Server 1
VM 1
VM 2
VM 3
Server 3
VM 7
VM 8
VM 9
Server 2
VM 4
VM 5
VM 6
FGE1/0/1
FGE1/0/2
FGE1/0/1
VX
LA
N tu
nne
l
VTEP 3
VXLAN tunnel
Server 4
VM 10
VM 11
VM 12
Replicate
Encapsulate
with multicast
address