H3C Technologies H3C S12500-X Series Switches - Manual (Page 71)

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Intra-VXLAN traffic forwarding between sites
As shown in Figure 16 , the network uses the following process to forward traffic in a VXLAN between
sites (for example, from VM 1 to VM 4 in VXLAN 10):
1. VM 1 sends an ARP request to obtain the MAC address of VM 4.
2. GW 1 performs the following operations:
a. Creates an ARP entry for VM 1 and replies with the MAC address of VSI-interface 10 (the
gateway interface for VXLAN 10).
b. Replaces the sender MAC address of the ARP request with the MAC address of VSI-interface
10, and then floods the request to all remote VTEPs.
3. VM 1 creates an ARP entry for VM 4. The MAC address in the entry is the MAC address of
VSI-interface 10 on GW 1.
4. GW 2 (the VTEP for VM 4) performs the following operations:
a. De-encapsulates the ARP request and creates an ARP entry for VM 1. The entry contains VM 1's
IP address (10.1.1.11), the MAC address of VSI-interface 10 on GW 1, and the incoming
tunnel interface.
b. Replaces the sender MAC address of the request with the MAC address of VSI-interface 10 on
GW 2, and then floods the request to the local site in VXLAN 10.
5. VM 4 creates an ARP entry for VM 1, and then sends a reply to GW 2. The MAC address in the
ARP entry is the MAC address of VSI-interface 10 on GW 2.
6. GW 2 performs the following operations:
a. Creates an ARP entry for VM 4.
b. Replaces the sender MAC address of the request with the MAC address of VSI-interface 10 on
GW 2, and sends the reply to GW 1.
7. GW 1 de-encapsulates the ARP request and creates an ARP entry for VM 4. The entry contains VM
4's IP address (10.1.1.12), the MAC address of VSI-interface 10 on GW 2, and the incoming
tunnel interface.
8. For subsequent traffic between VM 1 and VM 4, GW 1 and GW 2 use their respective ARP tables
to make the forwarding decision.
Inter-VXLAN traffic forwarding between sites
As shown in Figure 16 , the network uses the following process to forward traffic between VXLANs (for
example, from VM 1 in VXLAN 10 to VM 5 in VXLAN 20):
1. VM 1 sends an ARP request to obtain the MAC address of the gateway at 10.1.1.1.
2. GW 1 creates an ARP entry for VM 1 and replies with the MAC address of VSI-interface 10 (the
gateway interface for VXLAN 10).
3. VM 1 sends the packet destined for VM 5 to GW 1.
4. GW 1 sends an ARP request to the local site and remote sites to obtain the MAC address of VM
5.
5. GW 2 performs the following operations:
a. De-encapsulates the ARP request and creates an ARP entry for VM 1. The entry contains VM 1's
IP address (10.1.1.11), the MAC address of VSI-interface 10 on GW 1, and the incoming
tunnel interface.
b. Replaces the sender MAC address of the request with the MAC address of VSI-interface 20 on
GW 2, and then floods the request to the local site in VXLAN 20.