Arp Flood Suppression - H3C S10500 Series Configuration Manual

7. The source VM sends an ARP request to obtain the MAC address of the destination VM.
8. The gateway replies to the source VM with the MAC address of the VSI interface associated
with the source VM's VSI.
9. The source VM sends a Layer 3 packet to the gateway.
10. The gateway looks up the FIB table of the VPN instance associated with the source VM's VSI
and finds the matching outgoing VSI interface.
11. The gateway processes the Ethernet header of the Layer 3 packet as follows:
Replaces the destination MAC address with the destination gateway's router MAC address.
Replaces the source MAC address with its own router MAC address.
12. The gateway adds VXLAN encapsulation to the Layer 3 packet and forwards the packet to the
destination gateway. The encapsulated VXLAN ID is the L3 VXLAN ID of the corresponding
VPN instance.
13. The destination gateway identifies the VPN instance of the packet based on the L3 VXLAN ID
and removes the VXLAN encapsulation. Then the gateway forwards the packet based on the
matching ARP entry.
Figure 11 Inter-site Layer 3 forwarding
VM 1
Server 1
DMAC: GW MAC
SMAC: MAC 1
DIP: IP 2
SIP: IP 1
DATA

ARP flood suppression

ARP flood suppression reduces ARP request broadcasts by enabling the VTEP to reply to ARP
requests on behalf of VMs.
As shown in
populate the ARP flood suppression table with local and remote MAC addresses. If an ARP request
has a matching entry, the VTEP replies to the request on behalf of the VM. If no match is found, the
VTEP floods the request to both local and remote sites.
GW IP
GW MAC (VSI interface MAC)
GW MAC 1 (Router MAC of GW 1)
VTEP IP 1
L3VNI 100
IP 1
MAC 1
GW 1
DIP: VTEP IP 2
SIP: VTEP IP 1
DMAC: GW MAC 2
SMAC: GW MAC 1
Figure 12, this feature snoops ARP requests, ARP responses, and BGP EVPN routes to
P
Transport
network
VNI: 100
DIP: IP 2
SIP: IP 1
DATA
10
GW IP
GW MAC (VSI interface MAC)
GW MAC 2 (Router MAC of GW 2)
VTEP IP 2
L3VNI 100
IP 2
MAC 2
VM 2
Server 2
GW 2
DMAC: MAC 2
SMAC: GW MAC
DIP: IP 2
SIP: IP 1
DATA