Huawei AR1200 series Configuration Manual page 253

Huawei AR1200 Series Enterprise Routers
Configuration Guide - VPN
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Configuration Files
l
Issue 01 (2012-04-20)
NOTE
In this example, both PE2 and PE3 advertise the route 10.3.1.0/24 with the same BGP attribute to PE1.
The router ID of PE2 is smaller than that of PE3 so that PE1 preferentially selects the route advertised by
PE2, that is, Link_A. If the router ID of PE2 is greater than that of PE3 in a real-world situation, PE1
preferentially selects the route advertised by PE2, that is, Link_B. In this case, VPN FRR fails if the
preceding configurations are followed. To prevent the problem from occurring, you can modify VPNv4
route attributes in the BGP-VPNv4 address family view, ensuring that PE1 preferentially selecting Link_A.
There are many methods to modify VPNv4 route attributes. The following part shows the most common
two methods:
l In the BGP-VPNv4 address family view of PE1, set a higher PrefVal for the routes learnt from PE2.
The relevant configuration is as follows:
route-policy policy1 permit node 10
apply preferred-value 100
#
bgp 100
#
ipv4-family vpnv4
peer 2.2.2.2 route-policy policy1 import
l In the BGP-VPNv4 address family view of PE2, set a higher Local_Pref for the advertised routes. The
relevant configuration is as follows:
route-policy policy2 permit node 10
apply local-preference 200
#
bgp 100
#
ipv4-family vpnv4
peer 1.1.1.1 route-policy policy2 export
Configuration file of the PE1
#
sysname PE1
#
bfd
#
ip vpn-instance vpn1
ipv4-family
route-distinguisher 100:1
vpn frr route-policy vpn_frr_rp
vpn-target 111:1 export-extcommunity
vpn-target 111:1 import-extcommunity
#
mpls lsr-id 1.1.1.1
mpls
#
mpls ldp
#
interface Pos2/0/0
link-protocol ppp
ip address 100.1.1.1 255.255.255.252
mpls
mpls ldp
#
interface Pos3/0/0
link-protocol ppp
ip address 100.2.1.1 255.255.255.252
mpls
mpls ldp
#
interface LoopBack1
ip address 1.1.1.1 255.255.255.255
#
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3 BGP MPLS IP VPN Configuration
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