Configuring BGP AS number substitution and SoO attribute
Network requirements
CE 1, CE 2, and CE 3 belong to VPN 1, and are connected to PE1, PE 2, and PE 3. CE 1 and CE 2 reside in the same site. CE1, CE2, and CE 3 all use AS number 600.
To avoid route loss, configure BGP AS number substitution on PEs.
To avoid routing loops, configure the same SoO attribute on PE 1 and PE 2 for CE 1 and CE 2.
Figure 99: Network diagram
Table 37: Interface and IP address assignment
Device | Interface | IP address | Device | Interface | IP address |
|---|---|---|---|---|---|
CE 1 | Loop0 | 100::1/96 | CE 3 | Loop0 | 200::1/96 |
GE2/1/1 | 10:1::1/96 | GE2/1/1 | 10:3::1/96 | ||
CE 2 | GE2/1/1 | 10:2::1/96 | PE 2 | Loop0 | 2.2.2.9/32 |
PE 1 | Loop0 | 1.1.1.9/32 | GE2/1/1 | 10:2::2/96 | |
GE2/1/1 | 10:1::2/96 | GE2/1/2 | 40.1.1.1/24 | ||
GE2/1/2 | 20.1.1.1/24 | GE2/1/3 | 20.1.1.2/24 | ||
GE2/1/3 | 30.1.1.1/24 | P | Loop0 | 3.3.3.9/32 | |
PE 3 | Loop0 | 4.4.4.9/32 | GE2/1/1 | 30.1.1.2/24 | |
GE2/1/1 | 10:3::2/96 | GE2/1/2 | 40.1.1.2/24 | ||
GE2/1/2 | 50.1.1.2/24 | GE2/1/3 | 50.1.1.1/24 |
Configuration procedure
Configure basic IPv6 MPLS L3VPN:
Configure OSPF on the MPLS backbone to allow the PEs and P device to learn the routes of the loopback interfaces from each other.
Configure basic MPLS and MPLS LDP on the MPLS backbone to establish LDP LSPs.
Establish an MP-IBGP peer relationship between the PEs to advertise VPN IPv6 routes.
Configure the VPN instance of VPN 1 on PE 1 to allow CE 1 to access the network.
Configure the VPN instance of VPN 1 on PE 2 to allow CE 2 to access the network.
Configure the VPN instance of VPN 1 on PE 3 to allow CE 3 to access the network.
Configure BGP as the PE-CE routing protocol, and redistribute routes of the CEs into the PEs.
For more information about basic MPLS L3VPN configurations, see "Configuring IPv6 MPLS L3VPNs."
Configure BGP AS number substitution:
# Configure BGP AS number substitution on PE 1, PE 2, and PE 3. For more information about the configuration, see "Configuring BGP AS number substitution."
# Display routing information on CE 2. The output shows that CE 2 has learned the route 100::/96 from CE 1. A routing loop has occurred because CE 1 and CE 2 reside in the same site.
<CE2> display bgp routing-table ipv6 peer 10:2::2 received-routes Total number of routes: 2 BGP local router ID is 12.1.1.3 Status codes: * - valid, > - best, d - dampened, h - history, s - suppressed, S - stale, i - internal, e - external Origin: i - IGP, e - EGP, ? - incomplete * >e Network : 100:: PrefixLen : 96 NextHop : 10:2::2 LocPrf : PrefVal : 0 OutLabel : NULL MED : Path/Ogn: 100 100? * >e Network : 200:: PrefixLen : 96 NextHop : 10:2::2 LocPrf : PrefVal : 0 OutLabel : NULL MED : Path/Ogn: 100 100?Configure BGP SoO attribute:
# On PE 1, configure the SoO attribute as 1:100 for CE 1.
<PE1> system-view [PE1] bgp 100 [PE1-bgp-default] ip vpn-instance vpn1 [PE1-bgp-default-vpn1] address-family ipv6 [PE1-bgp-default-ipv6-vpn1] peer 10:1::1 soo 1:100
# On PE 2, configure the SoO attribute as 1:100 for CE 2.
[PE2] bgp 100 [PE2-bgp-default] ip vpn-instance vpn1 [PE2-bgp-default-vpn1] address-family ipv6 [PE2-bgp-default-ipv6-vpn1] peer 10:2::1 soo 1:100
Verifying the configuration
# PE 2 does not advertise routes received from CE 1 to CE 2 because the same SoO attribute has been configured. Display the routing table of CE 2. The output shows that the route 100::/96 has been removed.
<CE2> display ipv6 routing-table
Destinations : 4 Routes : 4
Destination: ::1/128 Protocol : Direct
NextHop : ::1 Preference: 0
Interface : InLoop0 Cost : 0
Destination: 10:2::/96 Protocol : Direct
NextHop : :: Preference: 0
Interface : GE2/1/1 Cost : 0
Destination: 10:2::1/128 Protocol : Direct
NextHop : ::1 Preference: 0
Interface : InLoop0 Cost : 0
Destination: 200::/96 Protocol : Static
NextHop : :: Preference: 60
Interface : NULL0 Cost : 0