Internet-Draft | MVPN in IPv6 Infrastructure | October 2021 |
Duan & Xie | Expires 26 April 2022 | [Page] |
MVPN deployment faces some problems while used in provider's IPv6 infrastructure networks. This document describes these problems, and the solutions to solve these problems.¶
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BGP MVPN procedure is defined in [RFC6514]. As a mature MVPN technology, it has been accepted by most operators and vendors. In [RFC6515] , BGP MVPN is updated for IPv6 infrastructure networks. However, the deployment of BGP MVPN in IPv6 network still faces some problems. This document describes these problems, and the solutions to solve these problems.¶
Readers of this document are assumed to be familiar with the terminology and concepts of the documents listed as Normative References.¶
In [RFC6514], the following processes are not suitable if IPv6 infrastructure addresses are used in provider's netwroks:¶
In [RFC7716], zero RD is introduced in BGP MVPN NLRIs to enable Global Table Multicast service in provider's netwroks. In IPv6 infrastructure networks, Leaf PEs cannot send two distinct C-multicast route to two individual upstream root PEs for selctive forwarding, because the RD of the two roots is the same.¶
In the process of evolution to IPv6, IPv4 and IPv6 infrastructure addresses will coexist in the provider's network. The following figure is an example of BGP MVPN evolution to IPv6.¶
During the evolution process, IPv4 and IPv6 parallel BGP sessions are established between Provider Edge routers and Reflctor routers, if the BGP MVPN route send to all IPv4 and IPv6 BGP peer without any control, the number of the PATHs of these routes will be doubled with each reflection while BGP [ADD-PATH] procedure is enabled on Reflctor routers.¶
To support non-segmented inter-AS tunnels in IPv6 infrastructure network, the C-Multicast route NLRI is redifined as following:¶
+-----------------------------------+ | RD (8 octets) | +-----------------------------------+ | Root Distinguisher (4 octets) | +-----------------------------------+ | Multicast Source Length (1 octet) | +-----------------------------------+ | Multicast Source (variable) | +-----------------------------------+ | Multicast Group Length (1 octet) | +-----------------------------------+ | Multicast Group (variable) | +-----------------------------------+¶
In the above figure, the Root Distinguisher field replaces the Source As field defined in [RFC6514]. When constructing a C-Multicast route, leaf PE follows the following specification:¶
When receiving a C-Multicast route from E-BGP neighbours, the ASBR checks whether an IPv6 VRF Route Import Extended Community is include in this route and takes following actions:¶
To reduce BGP MVPN routes in Parallel IPv4 and IPv6 BGP sessions networks, the following actions should be taken by sender PEs:¶
In the reflector routers, the part of routes which are received from IPv6 BGP neighbors will be reflected to other IPv6 BGP neighbors and the other part of routes which are received from IPv4 BGP neighbors will be reflected to other IPv4 BGP neighbors.¶
This document introduces no new security considerations beyond those already specified in [RFC6514] and [RFC6515].¶
This document contains no actions for IANA.¶
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