Mpls L3Vpn Configuration Task List; Configuring Basic Mpls L3Vpn - HP 10500 SERIES Configuration Manual

With the BGP AS number substitution function, when a PE advertises a route to a CE of the specified peer,
if an AS number identical to that of the CE exist in the AS_PATH of the route, it is replaced with that of the
PE.
After you enable the BGP AS number substitution function, the PE re-advertises all routing information to
the connected CEs in the peer group, performing BGP AS number substitution based on the previous
principle.
Figure 30 Application of BGP AS number substitution and SoO
EBGP_Update: 10.1.0.0/16
AS_PATH: 800
AS 800
Site 1
In Figure 30, both Site and Site 2 use the AS number of 800. AS number substitution is enabled on PE
2 for CE 2. Before advertising updates received from CE 1 to CE 2, PE 2 finds that an AS number in the
AS_PATH is the same as that of CE 2 and hence substitutes its own AS number 100 for the AS number.
In this way, CE 2 can normally receive the routing information from CE 1.
However, the AS number substitution function also introduces a routing loop in Site 2 because route
updates originated from CE 3 can be advertised back to Site 2 through PE 2 and CE 2. To remove the
routing loop, you can configure a routing policy on PE 2 to add the SoO attribute to route updates
received from CE 2 and CE 3 so that PE 2 does not advertise route updates from CE 3 to CE 2.

MPLS L3VPN configuration task list

Task

Configuring basic MPLS L3VPN

Configuring inter-AS VPN
Configuring nested VPN
Configuring HoVPN
Configuring an OSPF sham link
Configuring BGP AS number substitution and SoO
Configuring basic MPLS L3VPN
The key task in MPLS L3VPN configuration is to manage the advertisement of VPN routes on the MPLS
backbone, including PE-CE route exchange and PE-PE route exchange.
To configure basic MPLS L3VPN:
AS 100
PE 1
MPLS backbone
VPNv4_Update: 10.1.0.0/16
RD: 100:1
AS_PATH: 800
CE 1
248
CE 3
PE 2
AS 800
Site 2
EBGP_Update: 10.1.0.0/16
AS_PATH: 100, 100
CE 2
Remarks
By configuring basic MPLS L3VPN, you can construct
simple VPN networks over an MPLS backbone.
To deploy special MPLS L3VPN networks, such as
inter-AS VPN, and nested VPN, you must also perform
some specific configurations in addition to the basic
MPLS L3VPN configuration. For more information, see
the related sections.