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As shown in
, the IPv6 MPLS L3VPN packet forwarding procedure is as follows:
1.
The PC at Site 1 sends an IPv6 packet destined for 2001:2::1, the PC at Site 2. CE 1 transmits the
packet to PE 1.
2.
Based on the inbound interface and destination address of the packet, PE 1 finds a matching entry
from the routing table of the VPN instance, labels the packet with both a private network label
(inner label) and a public network label (outer label), and forwards the packet out.
3.
The MPLS backbone transmits the packet to PE 2 by outer label. The outer label is removed from
the packet at the penultimate hop.
4.
According to the inner label and destination address of the packet, PE 2 searches the routing table
of the VPN instance to determine the outbound interface, and then forwards the packet out of the
interface to CE 2.
5.
CE 2 forwards the packet to the destination by IPv6 forwarding.
IPv6 MPLS L3VPN routing information advertisement
The routing information for a local CE is advertised to the remote CE by using the following process:
1.
From the local CE to the ingress PE.
The local CE advertises standard IPv6 routing information to the ingress PE over an IPv6 static route,
RIPng route, OSPFv3 route, IPv6 IS-IS route, IBGP route, or EBGP route.
2.
From the ingress PE to the egress PE.
After receiving the standard IPv6 routes from the CE, the ingress PE performs the following
operations:
a.
Adds RDs and route targets to create VPN-IPv6 routes.
b.
Saves the routes to the routing table of the VPN instance created for the CE.
c.
Assigns VPN labels for the routes.
d.
Advertises the VPN-IPv6 routes to the egress PE through MP-BGP.
The egress PE performs the following operations:
a.
Compares the export target attributes of the VPN-IPv6 routes with the import target attributes
that it maintains for the VPN instance.
b.
Adds the routes to the routing table of the VPN instance if the export and import target
attributes are the same.
The PEs use an IGP to ensure the connectivity between them.
3.
From the egress PE to the remote peer CE.
The egress PE restores the original IPv6 routes and advertises them to the remote CE over an IPv6
static route, RIPng route, OSPFv3 route, IPv6 IS-IS route, EBGP, or IBGP route.
IPv6 MPLS L3VPN network schemes and features
IPv6 MPLS L3VPN supports the following network schemes and features:
•
Basic VPN.
•
Inter-AS VPN option A.
•
Inter-AS VPN option C.
•
Carrier's carrier.
