H3C Technologies H3C S12500-X Series Switches - Manual (Page 68)

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Centralized VXLAN IP gateway deployment
As shown in Figure 13 , a VTEP acts as a gateway for VMs in the VXLANs. The VTEP both terminates the
VXLANs and performs Layer 3 forwarding for the VMs. In this solution, the VTEP provides gateway
services for VXLANs on virtual Layer 3 VSI interfaces.
Figure 13 Centralized VXLAN IP gateway deployment
As shown in Figure 14 , the network uses the following process to forward Layer 3 traffic from VM 10.1.1.11
to the Layer 3 network:
1. The VM sends an ARP request to obtain the MAC address of the gateway (VTEP 3) at 10.1.1.1.
2. VTEP 1 floods the ARP request to all remote VTEPs.
3. VTEP 3 de-encapsulates the ARP request, creates an ARP entry for the VM, and sends an ARP reply
to the VM.
4. VTEP 1 forwards the ARP reply to the VM.
5. The VM learns the MAC address of the gateway, and sends the Layer 3 traffic to the gateway.
6. VTEP 3 removes the VXLAN encapsulation and inner Ethernet header for the traffic, and forwards
the traffic to the destination node.
Inter-VXLAN forwarding is the same as this process except for the last step. At the last step of inter-VLAN
forwarding, the gateway replaces the source-VXLAN encapsulation with the destination-VXLAN
encapsulation, and then forwards the traffic.