Cisco Cisco Packet Data Interworking Function (PDIF) Guía De Administador
BGP MPLS VPNs
▀ IPv6 Support for BGP MPLS VPNs
▄ Cisco ASR 5000 System Administration Guide
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IPv6 Support for BGP MPLS VPNs
Overview
The ASR 5x00 supports VPNv6 as described in RFC 4659 – BGP-MPLS IP Virtual Private Network (VPN) Extension
for IPv6 VPN.
for IPv6 VPN.
An IPv6 VPN is connected over an IPv6 interface or sub-interface to the Service Provider (SP) backbone via a PE
router. The site can be both IPv4 and IPv6 capable. Each VPNv6 has its own address space which means a given
address denotes different systems in different VPNs. This is achieved via a VPNv6 address-family which prepends a
Route Distinguisher (RD) to the IP address.
router. The site can be both IPv4 and IPv6 capable. Each VPNv6 has its own address space which means a given
address denotes different systems in different VPNs. This is achieved via a VPNv6 address-family which prepends a
Route Distinguisher (RD) to the IP address.
A VPNv6 address is a 24-byte quantity beginning with an 8-byte RD and ending with a 16-byte IPv6 address. When a
site is IPv4 and IPv6 capable, the same RD can be used for the advertisement of both IPv4 and IPv6 addresses.
site is IPv4 and IPv6 capable, the same RD can be used for the advertisement of both IPv4 and IPv6 addresses.
The system appends RD to IPv6 routes and exchanges the labeled IPv6-RD using the VPNv6 address-family. The
Address Family Identifier (AFI) and Subsequent Address Family Identifier (SAFI) fields for VPNv6 routes will be set to
2 and 128 respectively.
Address Family Identifier (AFI) and Subsequent Address Family Identifier (SAFI) fields for VPNv6 routes will be set to
2 and 128 respectively.
The IPv6 VPN traffic will be transported to the BGP speaker via IPv4 tunneling. The BGP speaker advertises to its peer
a Next Hop Network Address field containing a VPN-IPv6 address whose 8-octet RD is set to zero and whose 16-octet
IPv6 address is encoded as an IPv4-mapped IPv6 address (RFC 4291) containing the IPv4 address of the advertising
router. It is assumed that only EBGP peering will be used to exchange VPNv6 routes.
a Next Hop Network Address field containing a VPN-IPv6 address whose 8-octet RD is set to zero and whose 16-octet
IPv6 address is encoded as an IPv4-mapped IPv6 address (RFC 4291) containing the IPv4 address of the advertising
router. It is assumed that only EBGP peering will be used to exchange VPNv6 routes.
Support for VPN-IPv6 assumes the following:
Dual Stack (IPv4/IPv6) routing
IPv6 pools in VRFs
BGP peering over a directly connected IPv4 interface
See the figure below.
Figure 20. IPv6-RD Support for VPNv6