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Configuring ADVPN 
Overview 
Auto Discovery Virtual Private Network (ADVPN) enables enterprise branches that use dynamic 
public addresses to establish a VPN network. ADVPN uses the VPN Address Management (VAM) 
protocol to collect, maintain, and distribute dynamic public addresses. 
VAM uses the client/server model. All VAM clients register their public addresses on the VAM server. 
A VAM client obtains the public addresses of other clients from the server to establish ADVPN 
tunnels. 
ADVPN structures 
ADVPN uses domains to identify VPNs. VAM clients in a VPN must be assigned to the same ADVPN 
domain. A VAM client can belong to only one ADVPN domain. A VAM server can serve multiple 
ADVPN domains and manage their clients. 
VAM clients include hubs and spokes. 
• Hub—A hub is the exchange center of routing information. A hub in a hub-spoke network is also 
a data forwarding center. 
• Spoke—A spoke is the gateway of a branch. It does not forward data received from other 
ADVPN nodes. 
ADVPN supports the following structures: 
• Full-mesh—In a full-mesh ADVPN, spokes can directly communicate with each other. The hub 
acts as the route exchange center. 
As shown in Figure 142, th
e spokes register with the VAM server and get hub information in the 
ADVPN domain. Then, they establish permanent tunnels to the hub. 
Any two spokes can establish a dynamic tunnel to directly exchange data. The tunnel is deleted 
if no data exists during the idle timeout time. 
Figure 142 Full-mesh ADVPN