3Com MSR 50 Series, Configuration Manual

Page: 1465 / 2443

MPLS L3VPN Overview 1465
Figure 408 Network diagram for basic VPN networking scheme
In Figure 408 , for example, the VPN target for VPN 1 is 100:1 on the PEs, while
that for VPN 2 is 200:1. The two VPN 1 sites can communicate with each other,
and the two VPN 2 sites can communicate with each other. However, the VPN 1
sites cannot communicate with the VPN 2 sites.
Hub and spoke networking scheme
For a VPN where a central access control device is required and all users must
communicate with each other through the access control device, the hub and
spoke networking scheme can be used to implement the monitoring and filtering
of user communications.
This networking scheme requires two VPN targets: one for the “hub” and the
other for the “spoke”.
The VPN target setting rules for VPN instances of all sites on PEs are as follows:
■
On spoke PEs (that is, the PEs connected with spoke sites), set the export target
attribute to Spoke and the import target attribute to Hub.
■
On the hub PE (that is, the PE connected to the hub site), specify two interfaces
or sub-interfaces, one for receiving routes from spoke PEs, and the other for
advertising routes to spoke PEs. Set the import target attribute of the VPN
instance for the former to Spoke, and the export target attribute of the VPN
instance for the latter to Hub.
CE
CE CE
CE
PE PE P
Site 2
Site 1 Site 3
Site 4
VPN 1
VPN 1
VPN 2
VPN 2
VPN 1:
Import:100:1
Export:100:1
VPN 2:
Import:200:1
Export:200:1
VPN 2:
Import:200:1
Export:200:1
VPN 1:
Import:100:1
Export:100:1