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Configuring nested VPN
For a network with many VPNs, nested VPN is a good solution to implement layered management of
VPNs and to conceal the deployment of internal VPNs.
To build a nested VPN network, perform the following configurations:
•
Configurations between customer PE and customer CE
—Configure VPN instances on the customer
PE and configure route exchange between customer PE and customer CE.
•
Configurations between customer PE and provider CE
—Configure BGP VPNv4 route exchange
between them. To make sure the provider CE can receive all BGP VPNv4 routes, configure the
undo
policy vpn-target
command on the provider CE to not filter VPNv4 routes by RTs.
•
Configurations between provider CE and provider PE
—Configure VPN instances and enable
nested VPN on the provider PE and configure BGP VPNv4 route exchange between the provider CE
and provider PE.
•
Configurations between provider PEs
—Configure BGP VPNv4 route exchange between them.
Nested VPN allows a customer PE to directly exchange VPNv4 routes with a provider PE, without
needing to deploy a provider CE. In this case, the customer PE also acts as the provider CE. Therefore,
you must configure provider CE settings on it.
Configurations on the customer CE, customer PE, and provider CE are similar to basic MPLS L3VPN
configurations. This task describes the configurations on the provider PE.
When you configure nested VPN, follow these guidelines:
•
The address spaces of sub-VPNs of a VPN cannot overlap.
•
Do not assign nested VPN peers addresses that public network peers use.
•
Nested VPN does not support multihop EBGP. A provider PE and a provider CE must use the
addresses of the directly connected interfaces to establish a neighbor relationship.
To configure nested VPN:
Step Command
Remarks
1.
Enter system view.
system-view
N/A
2.
Enter BGP view.
bgp
as-number
N/A
3.
Enter BGP VPNv4 address
family view.
address-family vpnv4
N/A
4.
Enable nested VPN.
nesting-vpn
By default, nested VPN is disabled.
5.
Return to BGP view.
quit
N/A
6.
Enter BGP-VPN instance view.
ip vpn-instance
vpn-instance-name
N/A
7.
Specify the peer CE or the
peer group of the peer CE.
peer
{
group-name
|
peer-address
[
mask-length
] }
as-number
as-number
By default, no peer is specified.
8.
Create the BGP-VPN VPNv4
address family and enter its
view.
address-family vpnv4
By default, the BGP-VPN VPNv4
address family is not created.
