H3C S12500 Series Configuration Manual page 13

The source edge device forwards the encapsulated packet out of the EVI link to the destination
3.
edge device across the IP transport network.
The destination edge device removes the headers of the original Ethernet frame, looks up the
4.
destination MAC address in the MAC address table, and sends the frame out of the matching
outgoing interface.
Figure 5 Layer 2 forwarding between sites
Multicast flow
Edge devices run IPv4 IGMP snooping or IPv6 MLD snooping on each extended VLAN and learn
multicast router port and multicast member port information on EVI-Link interfaces for Layer 2 multicast
forwarding as if they were Ethernet interfaces. In an extended VLAN, each edge device tunnels IGMP,
MLD, and PIM protocol packets to all its remote edge devices, and the remote edge devices flood the
packets in the VLAN.
For a site-to-site multicast data frame in an extended VLAN, the following process (see
place:
The DR in a site sends out a multicast frame.
1.
The source edge device copies the frame and encapsulates one copy on each multicast member
2.
EVI-Link interface.
The source edge device unicasts the encapsulated frames to the destination edge devices over the
3.
EVI links.
Each destination edge device removes the headers of the multicast frame and copies the multicast
4.
frame on each multicast member interface.
Each destination edge device sends the multicast frame out of all member interfaces to the
5.
destination hosts.
6
Figure 6) takes