26
b.
Replaces the sender MAC address in the request with the MAC address of VSI-interface 20
on GW 2, and then sends the reply to GW 1.
8.
GW 1 de-encapsulates the ARP request and creates an ARP entry for Terminal 5. The entry
contains Terminal 5's IP address 20.1.1.12, the MAC address of VSI-interface 20 on GW 2, and
the incoming tunnel interface.
9.
For subsequent traffic between Terminal 1 and Terminal 5, GW 1 and GW 2 use their
respective ARP tables to make the forwarding decision.
VXLAN-to-external network traffic forwarding
As shown in
, the network uses the following process to forward traffic from a VXLAN to the
Layer 3 network (for example, from Terminal 1 to the host at 50.1.1.1):
1.
Terminal 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 Terminal 1 and replies with the MAC address of VSI-interface
10 (the gateway interface for VXLAN 10).
3.
Terminal 1 sends a packet destined for the host to GW 1.
4.
GW 1 performs the following operations:
a.
Searches the routing table for the next hop. In this example, the next hop for the packet is
10.1.1.2 (the border gateway).
b.
Floods an ARP request to the local and remote sites in VXLAN 10 to obtain the MAC
address of 10.1.1.2.
5.
The border gateway de-encapsulates the ARP request, creates an ARP entry for GW 1, and
tunnels a reply to GW 1.
6.
GW 1 de-encapsulates the ARP reply and creates an ARP entry for 10.1.1.2.
7.
GW 1 sends the packet destined for the host to the border gateway.
8.
The border gateway de-encapsulates the packet and forwards it to the host.
Configuration prerequisites
Before you configure a centralized or distributed VXLAN IP gateway, you must perform the following
tasks on VTEPs:
•
Enable Layer 3 forwarding for VXLANs.
•
Create VSIs and VXLANs.
•
Configure VXLAN tunnels and assign them to VXLANs.
Configuring a centralized VXLAN IP gateway
Step Command
Remarks
1.
Enter system view.
system-view
N/A
2.
Create a VSI interface and
enter VSI interface view.
interface vsi-interface
vsi-interface-id
By default, no VSI interfaces exist.
3.
Assign an IPv4 address to
the VSI interface.
ip
address
ip-address
{
mask
|
mask-length
}
By default, no IPv4 address is
assigned to a VSI interface.
4.
Return to system view.
quit
N/A
5.
Enter VSI view.
vsi
vsi-name
N/A
6.
Specify a gateway interface
for the VSI.
gateway vsi-interface
vsi-interface-id
By default, no gateway interface is
specified for a VSI.
