IPv4-Only and IPv6-Only PE Design DESIGN ALL SAFI

IPv4-Only and IPv6-Only PE Design DESIGN ALL SAFI Verizon Inc.

gyan.s.mishra@verizon.com

Juniper Networks, Inc.

smadhavi@juniper.net

Nokia

adam.1.simpson@nokia.com

Cisco Systems

821 Alder Drive, MILPITAS CALIFORNIA 95035 mankamis@cisco.com

Microsoft, Inc.

jefftant.ietf@gmail.com

Huawei Technologies

chenshuanglong@huawei.com

BESS Working Group As Enterprises and Service Providers upgrade their brown field or green field MPLS/SR core to an IPv6 transport, Multiprotocol BGP (MP-BGP)now plays an important role in the transition of their Provider (P) core network as well as Provider Edge (PE) Inter-AS peering network from IPv4 to IPv6. Operators must have flexiblity to continue to support IPv4 customers when both the Core and Edge networks migrate to IPv6. As well as must be able to support IPv6 networks in cases where operators decide to remain on an IPv4 network or during transition. This document details the External BGP (eBGP) PE-PE Inter-AS and PE-CE Edge peering IPv4-Only PE design where both IPv4 and IPv6 all supported SAFI NLRI can be advertised over a single IPv4 peer and IPv6-Only PE Design where all supported SAFI NLRI can be advertised over a single IPv6 peer. This document also defines a new IPv4 BGP next hop encoding standard that uses an IPv4 address as the next hop and not an IPv4 mapped IPv6 address. This document also provides vendor specific test cases for the IPv4-Only peering design and IPv6-Only PE design as well as test results for the four major vendors stakeholders in the routing and switching indusrty, Cisco, Juniper, Nokia and Huawei. With the test results provided for the IPv6-Only Edge peering design, the goal is that all other vendors around the world that have not been tested will begin to adopt and implement the design.

As Enterprises and Service Providers upgrade their brown field or green field MPLS/SR core to an IPv6 transport such as MPLS LDPv6, SR-MPLSv6 or SRv6, Multiprotocol BGP (MP-BGP) now plays an important role in the transition of the Provider (P) core networks and Provider Edge (PE) edge networks from IPv4 to IPv6. IXP are also facing IPv4 address depletion at their peering points, which are large Layer 2 transit backbones that service providers peer and exchange IPv4 and IPv6 Network Layer Reachability Information (NLRI). Today, these transit exchange points are Dual Stacked. With this IPv6-only BGP peering design, only IPv6 MUST be configured on the PE-PE inter-as peering interface, the Inter-AS Provider Edge (PE) - Provider Edge (PE), the IPv6 BGP peer is now used to carry IPv4 (Network Layer Reachability Information) NLRI over an IPv6 next hop using IPv6 next hop encoding defined in , while continuing to forward both IPv4 and IPv6 packets. With this IPv6-Only PE Design, ASBRs providing Inter-AS options peering PE to PE extending L3 VPN services is now no longer Dual Stacked and as well can support ALL AFI/SAFI. This document also provides a solution for use cases where operators are not yet ready to migrate to IPv6 or SRv6 core and would like to stay on IPv4-Only Core short to long term and maybe even indefinitely. With this design, operators can now remain with an IPv4-Only Core and do not have to migrate to an IPv6-Only Core. From a technical standpoint the underlay can remain IPv4 and still transport IPv6 NLRI to support IPv6 customers, and so does not need to be migrated to IPv6-Only underlay. With this IPv4-Only PE Design solution , IPv4 addressing only needs to be provisioned for the IPv4-Only PE-CE eBGP Edge peering design, thereby eliminating IPv6 provisioning at the Edge. This core and edge IPv4-Only peering design can apply to any eBGP peering, public internet or private, which can be either Core networks, Data Center networks, Access networks or can be any eBGP peering scenario. MP-BGP specifies that the set of usable next-hop address families is determined by the Address Family Identifier (AFI) and the Subsequent Address Family Identifier (SAFI). Historically the AFI/SAFI definitions for the IPv4 address family only have provisions for advertising a Next Hop address that belongs to the IPv4 protocol when advertising IPv4 or VPN-IPv4. specifies the extensions necessary to allow advertising IPv4 NLRI, Virtual Private Network Unicast (VPN-IPv4) NLRI, Multicast Virtual Private Network (MVPN-IPv4) NLRI with a Next Hop address that belongs to the IPv6 protocol. This comprises of an extended next hop encoding MP-REACH BGP capability exchange to allow the address of the Next Hop for IPv4 NLRI, VPN-IPv4 NLRI and MVPN-IPv4 NLRI to also belong to the IPv6 Protocol. defines the encoding of the Next Hop to determine which of the protocols the address actually belongs to, and a new BGP Capability allowing MP-BGP Peers to discover dynamically whether they can exchange IPv4 NLRI and VPN-IPv4 NLRI with an IPv6 Next Hop. With the new extensions defined in supporting NLRI and next hop address family mismatch, the BGP peer session can now be treated as a pure TCP transport and carry both IPv4 and IPv6 NLRI at the Provider Edge (PE) - Customer Edge (CE) over a single IPv6 TCP session. This allows for the elimination of dual stack from the PE-PE Inter-AS peering point, and now enable the Inter-AS peering to be IPv6-ONLY. The elimination of IPv4 Inter Provider ASBR tie point, PE-PE Inter-AS peering points translates into OPEX expenditure savings of point-to-point infrastructure links as well as /31 address space savings and administration and network management of both IPv4 and IPv6 BGP peers. This reduction decreases the number of PE-PE Inter-AS options BGP peers by fifty percent, which is a tremendous cost savings for operators. This document details an important External BGP (eBGP) PE-CE Edge and PE-PE Inter-AS IPv4-Only PE Design and IPv6-Only PE Peering Design that leverages the MP-BGP capability exchange by using single IPv4 peering or IPv6 peering as pure transport, allowing all IPv4 Network Layer Reachability Information (NLRI) and IPv6 Network Layer Reachability Information (NLRI)to be carried over the same (Border Gateway Protocol) BGP TCP session for all supported Subsequent Address Family Identifiers(SAFI). The design change provides two new alternative to traditional Dual Stacking implemnted today while providing the same Dual Stacking functionality and capabilities that exists today with separate IPv4 and IPv6 BGP sessions, but now with this paradigm shift now only requires a single IPv4 transport peer "IPv4-Only PE Design" or single IPv6 transport peer "IPv6-Only PE Design". IPv6-Only PE Design entails that an IPv4 address MUST not be configured on the PE-CE or PE-PE interface and with the IPv6-Only PE Design an IPv4 address must not be configured on the PE-CE or PE-PE interface. IPv4-Only PE Design entails that an IPv6 address MUST not be configured on the PE-CE or PE-PE interface and with the IPv4-Only PE Design an IPv6 address must not be configured on the PE-CE or PE-PE interface. From a control plane perspective with the IPv6-Only PE design a single IPv6-Only peer is required for both IPv4 and IPv6 routing updates and from a data plane forwarindg perspective an IPv6 address need only be configured on the PE-CE Edge or PE-PE Inter-AS peering interface for both IPv4 and IPv6 packet forwarding. From a control plane perspective with the IPv4-Only PE design a single IPv4-Only peer is required for both IPv4 and IPv6 routing updates and from a data plane forwarindg perspective an IPv4 address need only be configured on the PE-CE Edge or PE-PE Inter-AS peering interface for both IPv4 and IPv6 packet forwarding. This document defines the IPv6-Only PE Design and IPv4-Only PE Design as a new PE-CE Edge and ASBR-ASBR PE-PE Inter-AS BGP peering Standard to support all IPv4 and IPv6 AFI AFI and corresponding SAFI ubiquitously. As service providers migrate to Segment Routing architecture SR-MPLS and SRv6, VPN overlay exsits as well, and thus Inter-AS options Option-A, Option-B, Option-AB and Option-C are still applicable and thus this pardigm shift to IPv4-Only or IPv6-Only peering architecure is still very relevant to Segment Routing architecture both SR-MPLS and SRv6. With both the IPv4-Only PE Design and IPv6-Only PE Design, while the savings exists at the Edge eBGP PE-PE Inter-AS peering, on the core side iBGP PE to Route Reflector (RR) peering carrying <AFI/SAFI> IPv4 <1/1>, VPN-IPV4 <1/128>, and Multicasat VPN <1/129>, there is no savings as the Provider (P) Core is IPv6 Only or IPv4-Only, thus can only have an IPv6 peer and must use extended next hop encoding to carrying IPv4 NLRI IPV4 <2/1>, VPN-IPV4 <2/128>, and Multicast VPN <2/129> over an IPv4 or IPv6 next hop. The IPv4-Only PE Design and IPv6-Only PE ALL SAFI Design supports the following IPv4 and IPv6 AFI and their corresponding SAFI below: <AFI/SAFI>, NLRI Multi-Segment Pseudowires <1/6>, BGP Tunnel Encapsulation SAFI <1/7>, Tunnel SAFI <1/6>, BGP MDT SAFI <1/66>, BGP 4to6 SAFI <1/67>, BGP 6to4 SAFI draft xx <1/8>, Layer 1 VPN Auto-Discovery <1/69>, SR-TE Policy SAFI draft <1/73>, BGP 6to4 SAFI draft <1/8>, SDN WAN Capabilities draft <1/74>, Classful-Transport SAFI draftxx <1/76>, Tunneled Traffic FlowSpec draftxx <1/77>, MCAST-TREE SAFI draft xx <1/78>, Route Target Constraints <1/132>, Dissemination of Flow Specification Rules <1/133>, L3 VPN Dissemination of Flow Specification Rules <1/1344>, VPN Auto-Discovery SAFI draftxx <1/140> This document provides proof of concept test results for the IPv4-Only PE Design and IPv6-Only PE design for 12 of the most common use cases with 3 of the most commonly used SAFI <AFI/SAFI> IPv4 <1/1>, VPN-IPV4 <1/128>, and Multicasat VPN <1/129>, with four major vendors stakeholders in the routing and switching indusrty, Cisco, Juniper, Nokia and Huawei. With the test results provided for the IPv6-Only Edge peering design, the goal is that all other vendors around the world that have not been tested will begin to adopt and implement this new best practice for eBGP IPv6-Only Edge peering. This will give confidence to operators to start the proliferation of the IPv4-Only PE Design and IPv6-Only PE design worldwide. This document provides a detalied analysis of all IPv4 and IPv6 address family and related SAFI that is supported with the IPv4-Only PE Design and IPv6-Only PE Design in Section 4. Thus this draft provides a test use case basis with the three SAFI tested, giving extensibility to all of the other SAFI that are supported for future testing and deployment by operators. This document also defines a new IPv4 next hop encoding for IPv6 NLRI over IPv4 Next Hop to uses 4 byte IPv4 address for the next hop and not a IPv4 mapped IPv6 address as the new standard. Today the IPv4 next hop encoding has mix of 4 octet IPv4 address for the next hop as well as IPv4 mapped IPv6 address. This is discussed in detail in section 10. The Major benefit from the IPv4-Only PE design is IPv6 address space savings and the ability to support IPv6 NLRI without configuring an IPv6 address at the PE-CE edge and PE-PE inter-as boundary and avoid having to upgrade to support IPv6 as well elimination of provisioning of IPv6 addressing and Network Operations and monitoring costs of tradditional Dual Stacked interfaces with IPv4 and IPv6 BGP peering which now translating into CAPEX and OPEX Savings. The Major benefit from the IPv6-Only PE design is IPv4 address space savings solving IPv4 address depletion issues and the ability to support IPv4 NLRI without configuring an IPv4 address at the PE-CE edge and PE-PE inter-as boundary, as well elimination of provisioning of IPv4 address and Network Operations and monitoring costs of traditional Dual Stacked interfaces with IPv4 and IPv6 BGP peering which now translates into CAPEX and OPEX Savings.

The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in BCP 14 when, and only when, they appear in all capitals, as shown here.

Terminolgoy used in defining the IPv6-Only Edge specification. AFBR: Address Family Border Router Provider Edge (PE). Edge: PE-CE Edge Network Provider Edge - Customer Edge Core: P Core Network Provider (P) 4to6 Softwire : IPv4 edge over an IPv6-Only core 6to4 Softwire: IPv6 edge over an IPv4-Only core E2E: End to End

This specification addresses a real issue that has been discussed at many operator with extremely large core networks around the world related migration to IPv6 underlay transport which can now be put off indefinitely. Operators around the world are clamoring for a solution as well that can help solve issues related to IPv4 address depletion at these large IXP peering points.

Problem Statement Dual Stacked Dual Stacked CE PE +-------+ IPv4 BGP Peer +-------+ | |---------------| | | CE | IPv6 BGP Peer | PE | | |---------------| | +-------+ +-------+ IPv4 forwarding IPv4 forwarding IPv6 forwarding IPv6 forwarding

________ Dual Stacked _____ / \ Dual Stacked PE / CE / \__/ \___ PE / CE +----+ +----+ / \ +------+ +-----+ | | | | |0====VPN Overlay Tunnel ==0| | | | | | | | | | \ | | | | | CE |--| PE |--\ IPv6-Only Core |----| PE |---| CE | | | | | \0=========Underlay =======0| | | | | +----+ +----+ \ __/ +------+ +-----+ IPv4 IPv6 BGP peer \ IP / MPLS / SR domain / IPv4 and IPv6 BGP peer IPv4 forwarding \__ __ / IPv4 forwarding IPv6 forwarding \_______/ \_____/ IPv6 forwarding

The IPv6-Only Edge design solution applies to ALL IPv4 Network Layer Reachability Information (NLRI) and IPv6 Network Layer Reachability Information (NLRI) over an IPv6-Only BGP Peering session. IPv6-Only PE Design is applicable to infrastructure networks such as Core networks, DC networks, Access networks as well as any PE-CE public or private network can now utilize this IPv6-Only Edge solution and reap the benefits immediately on IPv6 address space saving and CAPEX and OPEX savings. Six Groupings of AFI/SAFI Use Case Scenario for the IPv6-Only PE Design ALL SAFI Group-1 PE-CE Group-2 PE-PE Inter-AS Group-3 L1 and L2 VPN Group-4 Multicast Group-5 Tunnel Group-6 BGP, BGP Flowspec, BGP Misc Policy Group-1 Edge Customer IPv4/IPv6 NLRI PE-CE AFI / SAFI grouping (CP-DP) - "UNICAST" AFI/SAFI 1/1 IPv4 Unicast 2/1 IPv6 Unicast Group-1 Edge Customer IPv4/IPv6 NLRI PE-CE AFI / SAFI grouping (CP-DP) - "MULTICAST" AFI/SAFI 1/2 IPv4 Multicast 2/2 IPv6 Multicast AFI/SAFI 1/78 IPv4 MCAST-TREE SAFI 2/78 MCAST-TREE SAFI Group-2 ASBR-ASBR Inter-AS Customer IPv4/IPv6 NLRI AFI/SAFI grouping (CP-DP) - "UNICAST" Global Table AFI/SAFI 1/4 4PE L3 VPN AFI/SAFI 1/128 IPv4 VPN 2/128 IPv6 VPN AFI/SAFI 1/132 IPv4 RTC 2/132 IPv6 RTC AFI/SAFI 1/140 IPv4 VPN Auto Discovery 2/140 IPv6 VPN Auto Discovery Group-2 ASBR-ASBR Inter-AS Customer IPv4/IPv6 NLRI AFI/SAFI grouping (CP-DP) - "MULTICAST" Global Table AFI/SAFI 1/2 IPv4 Multicast 2/2 IPv6 Multicast L3 VPN AFI/SAFI 1/5 IPv4 MCAST-VPN 2/5 IPv6 MCAST-VPN AFI/SAFI 1/66 IPv4 BGP MDT SAFI 2/66 IPv6 BGP MDT SAFI AFI/SAFI 1/78 IPv4 MCAST-TREE SAFI 2/78 MCAST-TREE SAFI Group-3 - L1 and L2 VPN L2 VPN related NLRI control plane in BGP AFI/SAFI 1/6 IPv4 Multi Segment PW 2/6 IPv6 Multi Segment PW AFI/SAFI 1/69 L1 VPN Auto Discovery 2/69 L1 VPN Auto Discovery Group-4 - Tunnel AFI/SAFI 1/64 Tunnel-SAFI 2/64 Tunnel-SAFI AFI/SAFI 1/67 BGP 4over6 Tunnel SAFI 2/67 BGP 4over6 Tunnel SAFI AFI/SAFI 1/68 BGP 6over4 Tunnel SAFI 2/68 BGP 6over4 Tunnel SAFI Group-5 - BGP, BGP Flowspec, BGP Misc Policy AFI/SAFI 1/73 SR-TE Policy SAFI 2/73 SR-TE Policy SAFI AFI/SAFI 1/74 SD-WAN Capabilities 2/74 SD-WAN Capabilities AFI/SAFI 1/77 Tunneled Traffic Flowspec 2/77 Tunneled Traffic Flowspec AFI/SAFI 1/133 Dissemination of Flowspec Rules 2/133 133 Dissemination of Flowspec Rules AFI/SAFI 1/134 L3 VPN 133 Dissemination of Flowspec Rules 2/134 L3VPN Dissemination of Flowspec Rules AFI/SAFI 1/85 BGP MUP SAFI 2/85 BGP MUP SAFI

Solution applicable to all AFI/SAFI AFI/SAFI 1/X 2/X Where X = ALL SAFI +-------+ +-------+ | AS1 | IPv6 Only | AS2 | | PE1 |----------------| PE2 | | (ASBR)| IPv6 BGP Peer |(ASBR) | +-------+ +-------+ IPv4 forwarding IPv4 forwarding IPv6 forwarding IPv6 forwarding

The IPv4-Only Edge design solution applies to ALL IPv4 Network Layer Reachability Information (NLRI) and IPv6 Network Layer Reachability Information (NLRI) over an IPv4-Only BGP Peering session. IPv4-Only PE Design is applicable to infrastructure networks such as Core networks, DC networks, Access networks as well as any PE-CE public or private network can now utilize this IPv4-Only Edge solution and reap the benefits immeditately of CAPEX and OPEX savings. Six Groupings of AFI/SAFI Use Case Scenario for the IPv6-Only PE Design ALL SAFI Group-1 PE-CE Group-2 PE-PE Inter-AS Group-3 L1 and L2 VPN Group-4 Multicast Group-5 Tunnel Group-6 BGP, BGP Flowspec, BGP Misc Policy Group-1 Edge Customer IPv4/IPv6 NLRI PE-CE AFI / SAFI grouping (CP-DP) - "UNICAST" AFI/SAFI 1/1 IPv4 Unicast 2/1 IPv6 Unicast Group-1 Edge Customer IPv4/IPv6 NLRI PE-CE AFI / SAFI grouping (CP-DP) - "MULTICAST" AFI/SAFI 1/2 IPv4 Multicast 2/2 IPv6 Multicast AFI/SAFI 1/78 IPv4 MCAST-TREE SAFI 2/78 MCAST-TREE SAFI Group-2 ASBR-ASBR Inter-AS Customer IPv4/IPv6 NLRI AFI/SAFI grouping (CP-DP) - "UNICAST" Global Table AFI/SAFI 1/4 4PE L3 VPN AFI/SAFI 1/128 IPv4 VPN 2/128 IPv6 VPN AFI/SAFI 1/132 IPv4 RTC 2/132 IPv6 RTC AFI/SAFI 1/140 IPv4 VPN Auto Discovery 2/140 IPv6 VPN Auto Discovery Group-2 ASBR-ASBR Inter-AS Customer IPv4/IPv6 NLRI AFI/SAFI grouping (CP-DP) - "MULTICAST" Global Table AFI/SAFI 1/2 IPv4 Multicast 2/2 IPv6 Multicast L3 VPN AFI/SAFI 1/129 IPv4 MVPN 2/129 IPv6 MVPN AFI/SAFI 1/5 IPv4 MCAST-VPN 2/5 IPv6 MCAST-VPN AFI/SAFI 1/66 IPv4 BGP MDT SAFI 2/66 IPv6 BGP MDT SAFI AFI/SAFI 1/78 IPv4 MCAST-TREE SAFI 2/78 MCAST-TREE SAFI Group-3 - L1 and L2 VPN L2 VPN related NLRI control plane in BGP AFI/SAFI 1/6 IPv4 Multi Segment PW 2/6 IPv6 Multi Segment PW AFI/SAFI 1/69 L1 VPN Auto Discovery 2/69 L1 VPN Auto Discovery Group-4 - Multicast AFI/SAFI 1/8 IPv4 MCAST-VPLS 2/8 IPv6 MCAST-VPLS Group-5 - Tunnel AFI/SAFI 1/64 Tunnel-SAFI 2/64 Tunnel-SAFI AFI/SAFI 1/67 BGP 4over6 Tunnel SAFI 2/67 BGP 4over6 Tunnel SAFI AFI/SAFI 1/68 BGP 6over4 Tunnel SAFI 2/68 BGP 6over4 Tunnel SAFI Group-6 - BGP, BGP Flowspec, BGP Misc Policy AFI/SAFI 1/73 SR-TE Policy SAFI 2/73 SR-TE Policy SAFI AFI/SAFI 1/74 SD-WAN Capabilities 2/74 SD-WAN Capabilities AFI/SAFI 1/77 Tunneled Traffic Flowspec 2/77 Tunneled Traffic Flowspec AFI/SAFI 1/133 Dissemination of Flowspec Rules 2/133 133 Dissemination of Flowspec Rules AFI/SAFI 1/134 L3 VPN 133 Dissemination of Flowspec Rules 2/134 L3VPN Dissemination of Flowspec Rules AFI/SAFI 1/79 BGP-DPS Arista 2/79 BGP-DPS Arista AFI/SAFI 1/83 BGP CAR 2/83 BGP CAR AFI/SAFI 1/84 BGP VPN CAR 2/84 BGP VPN CAR AFI/SAFI 1/85 BGP MUP SAFI 2/85 BGP MUP SAFI

________ IPv4-Only _____ / \ IPv4-Only PE / CE / \__/ \___ PE / CE +----+ +----+ / \ +------+ +-----+ | | | | |0====VPN Overlay Tunnel ==0| | | | | | | | | | \ | | | | | CE |--| PE |--\ IPv4-Only Core |----| PE |---| CE | | | | | \0=========Underlay ===== ==0 | | | | +----+ +----+ \ __/ +------+ +-----+ IPv6 BGP peer \IP / MPLS / SR domain / IPv6 BGP peer IPv4 forwarding \__ __ / IPv4 forwarding IPv6 forwarding \_______/ \_____/ IPv6 forwarding

The IPv6-Only Edge Peering design utilizes two key E2E Softwire Mesh Framework scenario's, 4to6 softwire and 6to4 softwire. The Softwire mesh framework concept is based on the overlay and underlay MPLS or SR based technology framework, where the underlay is the transport layer and the overlay is a Virtual Private Network (VPN) layer, and is the the tunneled virtualization layer containing the customer payload. The concept of a 6to4 Softwire is based on transmission of IPv6 packets at the edge of the network by tunneling the IPv6 packets over an IPv4-Only Core. The concept of a 4to6 Softwire is also based on transmission of IPv4 packets at the edge of the network by tunneling the IPv4 packets over an IPv6-Only Core. This document describes End to End (E2E) test scenarios that follow a packet flow from IPv6-Only attachment circuit from ingress PE-CE to egress PE-CE tracing the routing protocol control plane and data plane forwarding of IPv4 packets in a 4to6 softwire or 6to4 softwire within the IPv4-Only or IPv6-Only Core network. In both secneario we are focusing on IPv4 packets and the control plane and data plane forwarding aspects of IPv4 packets from the PE-CE Edge network over an IPv6-Only P (Provider) core network or IPv4-Only P (Provider) core network. With this IPv6-Only Edge peering design, the Softwire Mesh Framework is not extended beyond the Provider Edge (PE) and continues to terminate on the PE router.

6to4 softwire where IPv6-Edge eBGP IPv6 peering where IPv4 packets at network Edge traverse a IPv4-Only Core In the scenario where IPv4 packets originating from a PE-CE edge are tunneled over an MPLS or Segment Routing IPv4 underlay core network, the PE and CE only have an IPv6 address configured on the interface. In this scenario the IPv4 packets that ingress the CE from within the CE AS are over an IPv6-Only interface and are forwarded to an IPv4 NLRI destination prefix learned from the Pure Transport Single IPv6 BGP Peer. In the IPv6-Only Edge peering architecture the PE is IPv6-Only as all PE-CE interfaces are IPv6-Only. However, on the CE, the PE-CE interface is the only interface that is IPv6-Only and all other interfaces may or may not be IPv6-Only. Following the data plane packet flow, IPv4 packets are forwarded from the ingress CE to the IPv6-Only ingress PE where the VPN label imposition push per prefix, per-vrf, per-CE occurs and the labeled packet is forwarded over a 6to4 softwire IPv4-Only core, to the egress PE where the VPN label disposition pop occurs and the native IPv4 packet is forwarded to the egress CE. In the reverse direction IPv4 packets are forwarded from the egress CE to egress PE where the VPN label imposition per prefix, per-vrf, per-CE push occurs and the labeled packet is forwarded back over the 6to4 softwire IPv4-Only core, to the ingress PE where the VPN label disposition pop occurs and the native IPv4 packet is forwarded to the ingress CE. . The functionality of the IPv4 forwarding plane in this scenario is identical from a data plane forwarding perspective to Dual Stack IPv4 forwarding scenario.

+--------+ +--------+ | IPv4 | | IPv4 | | Client | | Client | | Network| | Network| +--------+ +--------+ | \ / | | \ / | | \ / | | X | | / \ | | / \ | | / \ | +--------+ +--------+ | AFBR | | AFBR | +--| IPv4/6 |---| IPv4/6 |--+ | +--------+ +--------+ | +--------+ | | +--------+ | IPv4 | | | | IPv4 | | Client | | | | Client | | Network|------| IPv4 |-------| Network| +--------+ | only | +--------+ | | | +--------+ +--------+ | +--| AFBR |---| AFBR |--+ | IPv4/6 | | IPv4/6 | +--------+ +--------+ | \ / | | \ / | | \ / | | X | | / \ | | / \ | | / \ | +--------+ +--------+ | IPv6 | | IPv4 | | Client | | Client | | Network| | Network| +--------+ +--------+

4to6 softwire where IPv6-Edge eBGP IPv6 peering where IPv4 packets at network Edge traverse a IPv6-Only Core In the scenario where IPv4 packets originating from a PE-CE edge are tunneled over an MPLS or Segment Routing IPv4 underlay core network, the PE and CE only have an IPv6 address configured on the interface. In this scenario the IPv4 packets that ingress the CE from within the CE AS are over an IPv6-Only interface and are forwarded to an IPv4 NLRI destination prefix learned from the Pure Transport Single IPv6 BGP Peer. In the IPv6-Only Edge peering architecture the PE is IPv6-Only as all PE-CE interfaces are IPv6-Only. However, on the CE, the PE-CE interface is the only interface that is IPv6-Only and all other interfaces may or may not be IPv6-Only. Following the data plane packet flow, IPv4 packets are forwarded from the ingress CE to the IPv6-Only ingress PE where the VPN label imposition push per prefix, per-vrf, per-CE occurs and the labeled packet is forwarded over a 4to6 softwire IPv6-Only core, to the egress PE where the VPN label disposition pop occurs and the native IPv4 packet is forwarded to the egress CE. In the reverse direction IPv4 packets are forwarded from the egress CE to egress PE where the VPN label imposition per prefix, per-vrf, per-CE push occurs and the labeled packet is forwarded back over the 4to6 softwire IPv6-Only core, to the ingress PE where the VPN label disposition pop occurs and the native IPv4 packet is forwarded to the ingress CE. . The functionality of the IPv4 forwarding plane in this scenario is identical from a data plane forwarding perspective to Dual Stack IPv4 forwarding scenario.

+--------+ +--------+ | IPv4 | | IPv4 | | Client | | Client | | Network| | Network| +--------+ +--------+ | \ / | | \ / | | \ / | | X | | / \ | | / \ | | / \ | +--------+ +--------+ | AFBR | | AFBR | +--| IPv4/6 |---| IPv4/6 |--+ | +--------+ +--------+ | +--------+ | | +--------+ | IPv6 | | | | IPv6 | | Client | | | | Client | | Network|------| IPv6 |-------| Network| +--------+ | only | +--------+ | | | +--------+ +--------+ | +--| AFBR |---| AFBR |--+ | IPv4/6 | | IPv4/6 | +--------+ +--------+ | \ / | | \ / | | \ / | | X | | / \ | | / \ | | / \ | +--------+ +--------+ | IPv4 | | IPv4 | | Client | | Client | | Network| | Network| +--------+ +--------+

The IPv4-Only Edge Peering design utilizes two key E2E Softwire Mesh Framework scenario's, 4to6 softwire and 6to4 softwire. The Softwire mesh framework concept is based on the overlay and underlay MPLS or SR based technology framework, where the underlay is the transport layer and the overlay is a Virtual Private Network (VPN) layer, and is the the tunneled virtualization layer containing the customer payload. The concept of a 6to4 Softwire is based on transmission of IPv6 packets at the edge of the network by tunneling the IPv6 packets over an IPv4-Only Core. The concept of a 4to6 Softwire is also based on transmission of IPv4 packets at the edge of the network by tunneling the IPv4 packets over an IPv6-Only Core. This document describes End to End (E2E) test scenarios that follow a packet flow from IPv4-Only attachment circuit from ingress PE-CE to egress PE-CE tracing the routing protocol control plane and data plane forwarding of IPv4 packets in a 4to6 softwire or 6to4 softwire within the IPv4-Only or IPv6-Only Core network. In both secneario we are focusing on IPv4 packets and the control plane and data plane forwarding aspects of IPv4 packets from the PE-CE Edge network over an IPv4-Only P (Provider) core network or IPv6-Only P (Provider) core network. With this IPv4-Only Edge peering design, the Softwire Mesh Framework is not extended beyond the Provider Edge (PE) and continues to terminate on the PE router.

6to4 softwire where IPv4-Edge eBGP IPv4 peering where IPv6 packets at network Edge traverse a IPv4-Only Core In the scenario where IPv6 packets originating from a PE-CE edge are tunneled over an MPLS or Segment Routing IPv4 underlay core network, the PE and CE only have an IPv6 address configured on the interface. In this scenario the IPv6 packets that ingress the CE from within the CE AS are over an IPv4-Only interface and are forwarded to an IPv6 NLRI destination prefix learned from the Pure Transport Single IPv4 BGP Peer. In the IPv4-Only Edge peering architecture the PE is IPv4-Only as all PE-CE interfaces are IPv4-Only. However, on the CE, the PE-CE interface is the only interface that is IPv4-Only and all other interfaces may or may not be IPv4-Only. Following the data plane packet flow, IPv4 packets are forwarded from the ingress CE to the IPv4-Only ingress PE where the VPN label imposition push per prefix, per-vrf, per-CE occurs and the labeled packet is forwarded over a 6to4 softwire IPv4-Only core, to the egress PE where the VPN label disposition pop occurs and the native IPv4 packet is forwarded to the egress CE. In the reverse direction IPv4 packets are forwarded from the egress CE to egress PE where the VPN label imposition per prefix, per-vrf, per-CE push occurs and the labeled packet is forwarded back over the 6to4 softwire IPv4-Only core, to the ingress PE where the VPN label disposition pop occurs and the native IPv4 packet is forwarded to the ingress CE. . The functionality of the IPv4 forwarding plane in this scenario is identical from a data plane forwarding perspective to Dual Stack IPv4 forwarding scenario.

4to6 softwire where IPv4-Edge eBGP IPv4 peering where IPv6 packets at network Edge traverse a IPv6-Only Core In the scenario where IPv6 packets originating from a PE-CE edge are tunneled over an MPLS or Segment Routing IPv4 underlay core network, the PE and CE only have an IPv4 address configured on the interface. In this scenario the IPv6 packets that ingress the CE from within the CE AS are over an IPv4-Only interface and are forwarded to an IPv6 NLRI destination prefix learned from the Pure Transport Single IPv4 BGP Peer. In the IPv4-Only Edge peering architecture the PE is IPv4-Only as all PE-CE interfaces are IPv4-Only. However, on the CE, the PE-CE interface is the only interface that is IPv4-Only and all other interfaces may or may not be IPv4-Only. Following the data plane packet flow, IPv6 packets are forwarded from the ingress CE to the IPv4-Only ingress PE where the VPN label imposition push per prefix, per-vrf, per-CE occurs and the labeled packet is forwarded over a 4to6 softwire IPv6-Only core, to the egress PE where the VPN label disposition pop occurs and the native IPv6 packet is forwarded to the egress CE. In the reverse direction IPv6 packets are forwarded from the egress CE to egress PE where the VPN label imposition per prefix, per-vrf, per-CE push occurs and the labeled packet is forwarded back over the 4to6 softwire IPv6-Only core, to the ingress PE where the VPN label disposition pop occurs and the native IPv6 packet is forwarded to the ingress CE. . The functionality of the IPv4 forwarding plane in this scenario is identical from a data plane forwarding perspective to Dual Stack IPv4 / IPv6 forwarding scenario.

+--------+ +--------+ | IPv4 | | IPv4 | | Client | | Client | | Network| | Network| +--------+ +--------+ | \ / | | \ / | | \ / | | X | | / \ | | / \ | | / \ | +--------+ +--------+ | AFBR | | AFBR | +--| IPv4/6 |---| IPv4/6 |--+ | +--------+ +--------+ | +--------+ | | +--------+ | IPv6 | | | | IPv6 | | Client | | | | Client | | Network|------| IPv6 |-------| Network| +--------+ | only | +--------+ | | | +--------+ +--------+ | +--| AFBR |---| AFBR |--+ | IPv4/6 | | IPv4/6 | +--------+ +--------+ | \ / | | \ / | | \ / | | X | | / \ | | / \ | | / \ | +--------+ +--------+ | IPv4 | | IPv4 | | Client | | Client | | Network| | Network| +--------+ +--------+

RFC 4798 (6PE) section 2 defines how the next hop should be encoded for IPv6 NLRI over an IPv4 next hop using IPv4 mapped IPv6 address ::FFFF:192.168.1.1. RFC 4659 BGP MPLS VPNs section 3.2.1.2 defines VPN SAFI next hop encoding of IPv4 mapped IPv6 address ::FFFF:192.168.1.1. RFC 5549 and now updated by RFC 8950 defines the IPv6 next hop encoding to carry IPv4 NLRI over an IPv6 next hop. The IPv6 next hop encoding defined is not an IPv6 mapped IPv4 address. The IPv6 next hop encoding is 16/32 byte for Unicast SAFI 1, Multicast SAFI 2 and BGP-LU SAFI 4, and 24/48 byte for VPN SAFI 128, MVPN SAFI 129. The IANA BGP Capability codepoint defined with RFC 5549 is value 5 for Extended Next hop encoding. The industry implementation uses a mix of IPv4 mapped IPv6 address for IPv6 NLRI carried over an IPv4 address next hop and uses 4 byte field for IPv4 next hop address for Unicast SAFI 1, Multicast SAFI2 and BGP-LU SAFI 4, and 12 byte next hop field, 4 byte IPv4 address plus 8 byte RD (Route Distinguisher) set to 0 for VPN SAFI 128, MVPN SAFI 129. This draft standardizes the encoding to use an IPv4 address next hop and uses 4 byte field for IPv4 next hop address for Unicast SAFI 1, Multicast SAFI2 and BGP-LU SAFI 4, and 12 byte next hop field, 4 byte IPv4 address plus 8 byte RD (Route Distinguisher) set to 0 for VPN SAFI 128, MVPN SAFI 129. This draft standardizes that encoding to ensure interoperability with IANA BGP Capability codepoint allocation thus providing parity between the RFC 5549/RFC 8950 IPv6 next hop encoding where the next hop address follows the underlay core protocol which is an IPv6 core and how the next hop here being an IPv6 address and not following the NLRI protocol with IPv6 mapped IPv4 address. Now with this draft the next hop encoding follows the underlay core which is an IPv4 core and so now the next hop being an IPv4 address and not following the NLRI with an IPv4 mapped IPv6 address. So this parity between IPv4 next encoding and IPv6 next hop encoding savings in OPEX and operations troubleshooting as well as interoperability that all vendor implementations now use the same IPv4 next hop encoding is the reason the encoding must be standardized. This IPv4 next hop encoding is applicable for IPv6 NLRI for both iBGP control plane (CP) peering as well as eBGP PE-CE, PE-PE in-line control / data plane (CP-DP) peering which is used for IPv4-Only PE design as well as any IPv4 peering. The IPv4 Next hop encoding updates both RFC 4271 next hop path attribute and RFC MP-BGP RFC 4760 NLRI path attribute. Some of the major vendors across platforms even support a variety of different encodings as well in some cases on the same platform the control plane BGP encoding and hardware programming is even differnet and does not match up. For interoperability if a vendor does not support the new next hop encoding, it would continue to use the IPv4 mapped IPv6 address format until the P2P send / receive neighbors MP-BGP MP_REACH BGP capability exchange is for the new IPv4 Next hop encoding codepoint.

Listed below are the following IPv6-Only PE Design, design scenario's that have been tested with test results related to the two of the Most Common SAFIs used today listed below: <AFI/SAFI>, IPv4 Unicast <1/1>, IPv6 Unicast <2/1>, VPN-IPV4 <1/128>, VPN-IPV6 <2/128>, IPv6-Only PE Design Proof of conept interoperability testing of the 2 most common SAFI with 12 of the most common design use cases between the 4 vendors Cisco, Juniper, Nokia and Huawei. Cisco, Juniper, Nokia, Huawei, platform, code revision and test results for all use cases Cisco: Edge Router- XR ASR 9910 IOS XR 7.4.1, Core Router- NCS 6000 7.2.2, CRS-X 6.7.4, XRd (XR Docker) Cisco: All testing completed tests 1-12 on XRd 7.10.11 Global table and VRF and IPv4 MPLS core and IPv6 SRv6 core Juniper: Edge Router- MX platform MX480, MX960, Core Router- PTX Platform PTX5000, PTC10K8 (JUNOS and EVO) Release 20.4R2 All Testing 1-4 completed for Unicast SAFI 1/1 IPv4-Unicast, 2/1 IPv6-Unicast All Testing 5-12 completed for IP VPN SAFI 1/128 IPv4-VPN, 2/128 IPv6-VPN Tested v4 edge over v6 core in a virtual setup using vMX platforrm and 20.4R2 and LDPv6 as underlay, but there were some data plane forwarding issues. Tested same setup on latest release 21.4 and it worked. Investigating what the minimum version is for this setup to work. Tested on above Juniper platforms. Completed IPv6-Only PE design functionality test with PE-CE IPv6 peer carrying IPv4 and IPv6 prefixes control plane validation and data plane forwarding plane validation and verified end to end reachability CE to CE forwarding plane with Default Per-CE label allocation mode. Tested with IPv4-Only Core and IPv6-Only Core and proved that the IPv6-Only PE design solution works. Both IPv4 and IPv6 packets were forwarded identical functionality of Dual Stack without having IPv4 address configured. Nokia: Edge and Core-7750 Service Router, Release R21 All Testing 1-4 completed for Unicast SAFI 1/1 IPv4-Unicast, 2/1 IPv6-Unicast All Testing 5-12 completed for IP VPN SAFI 1/128 IPv4-VPN, 2/128 IPv6-VPN Huawei: Edge and Core-VRPv8, Release VRP-V800R020C10 Not Completed Juniper Mx960 24.2R1-S1.10 and Nokia IXR-X3 25.7.R1 interoperability testing completed over IPv4 MPLS core and IPv6 SRv6 Core, tests 1-12 completed successfully. No issues. IPv4 Only PE Design, IPv6-Only PE Design Test Cases 1-12 Intra-AS tests PE-CE Edge Peering IPv4-Only Core, IPv6-Only Core, Global Table (GRT) and IP VPN Test Cases 1-4 AFI/SAFI IPv4-Unicast SAFI 1/1 IPv6-Unicast SAFI 2/1 Test-1 Global table (6PE) Test-2 IP VPN AFI/SAFI IPv4-Unicast 1/1 SAFI IPv6-Unicast SAFI 2/1 Test-3 Global table (4PE) Test-4 IP VPN Inter-AS Options tests IPv4-Only Core, IPv6-Only Core, Global Table (GRT) and IP VPN Test Cases 5-12 AFI/SAFI IPv4-VPN SAFI 1/128 IPv6-VPN SAFI 2/128 Test-5 Global table 6PE Option-B Test-6 Global table 6PE Option-C Test-7 IP VPN Inter AS Option-B Test-8 IP VPN Inter AS Option-C AFI/SAFI IPv4-Unicast SAFI IPv6-Unicast SAFI Test-9 Global table Option-B Test-10 Global table Option-C Test-11 IP VPN Inter AS Option-B Test-12 IP VPN Inter AS Option-C

Listed below are the following IPv6-Only PE Design, design scenario's that have been tested with test results related to the 3 of the Most Common SAFIs used today listed below: <AFI/SAFI> IPv4 Unicast <1/1>, IPv6 Unicast <2/1>, VPN-IPV4 <1/128>, VPN-IPV6 <2/128>, Multicasat VPN <1/129>, Multicasat VPN <2/129>,BGP-LU IPV4 (GRT) <1/4>

________ IPv6-Only _____ / \ IPv6-Only PE / CE / \__/ \___ PE / CE +----+ +----+ / \ +------+ +-----+ | | | | | |_ | | | | | | | | | \ | | | | | CE |--| PE |--\ IPv4-Only Core |----| PE |---| CE | | | | | \0=========Underlay =======0| | | | | +----+ +----+ \ __/ +------+ +-----+ IPv6 BGP peer \ MPLS / SR domain / IPv6 BGP peer IPv4 forwarding \__ __ / IPv4 forwarding IPv6 forwarding \_______/ \_____/ IPv6 forwarding

________ IPv6-Only _____ / \ IPv6-Only PE / CE / \__/ \___ PE / CE +----+ +----+ / \ +------+ +-----+ | | | | | 0====VPN Overlay Tunnel ==0| | | | | | | | | | \ | | | | | CE |--| PE |--\ IPv4-Only Core |----| PE |---| CE | | | | | \0=========Underlay =======0| | | | | +----+ +----+ \ __/ +------+ +-----+ IPv6 BGP peer \ MPLS / SR domain / IPv6 BGP peer IPv4 forwarding \__ __ / IPv4 forwarding IPv6 forwarding \_______/ \_____/ IPv6 forwarding

________ IPv6-Only _____ / \ IPv6-Only PE / CE / \__/ \___ PE / CE +----+ +----+ / \ +------+ +-----+ | | | | | |_ | | | | | | | | | \ | | | | | CE |--| PE |--\ IPv6-Only Core |----| PE |---| CE | | | | | \0=========Underlay =======0| | | | | +----+ +----+ \ __/ +------+ +-----+ IPv6 BGP peer \ MPLS / SR domain / IPv6 BGP peer IPv4 forwarding \__ __ / IPv4 forwarding IPv6 forwarding \_______/ \_____/ IPv6 forwarding

________ IPv6-Only _____ / \ IPv6-Only PE / CE / \__/ \___ PE / CE +----+ +----+ / \ +------+ +-----+ | | | | | 0====VPN Overlay Tunnel ==0| | | | | | | | | | \ | | | | | CE |--| PE |--\ IPv6-Only Core |----| PE |---| CE | | | | | \0=========Underlay =======0| | | | | +----+ +----+ \ __/ +------+ +-----+ IPv6 BGP peer \ MPLS / SR domain / IPv6 BGP peer IPv4 forwarding \__ __ / IPv4 forwarding IPv6 forwarding \_______/ \_____/ IPv6 forwarding

Inter-AS ASBR-ASBR link is IPv6-Only PE IPv6-Only __________ __________ IPv6-Only PE / CE / \ / \ PE / CE +--+ +----+ / \ / \ +--+ +--+ | | | | | AS 1 \ | AS 2 \ | | | | | | | | | \IPv6| \ | | | | |CE|-| PE |--| IPv4-Only Core|----|IPv4-Only Core|--|PE|-|CE| | | | | |0=Underlay==0 | |0==Underlay==0| | | | | +--+ +----+ \ / \ / +--+ +--+ IPv6 BGP peer \ MPLS/SR / \ MPLS/SR / IPv6 BGP peer IPv4 forwarding \_________/ \_________/ IPv4 forwarding IPv6 forwarding IPv6 forwarding

Inter-AS ASBR-ASBR link is IPv6-Only PE IPv6-Only __________ __________ IPv6-Only PE / CE / \ / \ PE / CE +--+ +----+ / \ / \ +--+ +--+ | | | | | AS 1 \ | AS 2 \ | | | | | | | | | \IPv6| \ | | | | |CE|-| PE |--| IPv4-Only Core|----|IPv4-Only Core|--|PE|-|CE| | | | | |0=Overlay===0 | |0==Overlay===0| | | | | +--+ +----+ \ / \ / +--+ +--+ IPv6 BGP peer \ MPLS/SR / \ MPLS/SR / IPv6 BGP peer IPv4 forwarding \_________/ \_________/ IPv4 forwarding IPv6 forwarding IPv6 forwarding

Inter-AS ASBR-ASBR link is IPv6-Only PE IPv6-Only __________ __________ IPv6-Only PE / CE / \ / \ PE / CE +--+ +----+ / \ / \ +--+ +--+ | | | | | AS 1 \ | AS 2 \ | | | | | | | | | \IPv6| \ | | | | |CE|-| PE |--| IPv6-Only Core|----|IPv6-Only Core|--|PE|-|CE| | | | | |0=Underlay==0 | |0==Underlay==0| | | | | +--+ +----+ \ / \ / +--+ +--+ IPv6 BGP peer \ MPLS/SR / \ MPLS/SR / IPv6 BGP peer IPv4 forwarding \_________/ \_________/ IPv4 forwarding IPv6 forwarding IPv6 forwarding

Inter-AS ASBR-ASBR link is IPv6-Only PE IPv6-Only __________ __________ IPv6-Only PE / CE / \ / \ PE / CE +--+ +----+ / \ / \ +--+ +--+ | | | | | AS 1 \ | AS 2 \ | | | | | | | | | \IPv6| \ | | | | |CE|-| PE |--| IPv6-Only Core|--- |IPv6-Only Core|--|PE|-|CE| | | | | |0=Underlay==0 | |0==Underlay==0| | | | | +--+ +----+ \ / \ / +--+ +--+ IPv6 BGP peer \ MPLS/SR / \ MPLS/SR / IPv6 BGP peer IPv4 forwarding \_________/ \_________/ IPv4 forwarding IPv6 forwarding IPv6 forwarding

Inter-AS ASBR-ASBR link is IPv6-Only PE IPv6-Only __________ __________ IPv6-Only PE / CE / \ / \ PE / CE +--+ +----+ / \ / \ +--+ +--+ | | | | | AS 1 \ | AS 2 \ | | | | | | | | | \IPv6| \ | | | | |CE|-| PE |--| IPv6-Only Core|--- |IPv6-Only Core|--|PE|-|CE| | | | | |0=Overlay===0 | |0==Overlay===0| | | | | +--+ +----+ \ / \ / +--+ +--+ IPv6 BGP peer \ MPLS/SR / \ MPLS/SR / IPv6 BGP peer IPv4 forwarding \_________/ \_________/ IPv4 forwarding IPv6 forwarding IPv6 forwarding

Ping CE to PE when destination prefix is withdrawn Traceroute CE to PE and test all ICMPv4 and ICMPv6 type codes +-------+ +-------+ | | IPv6 Only | | | CE |----------------| PE | | | IPv6 BGP Peer | | +-------+ +-------+ IPv4 forwarding IPv4 forwarding IPv6 forwarding IPv6 forwarding

Listed below are the following IPv4-Only PE Design, design scenario's that have been tested with test results related to the 3 of the Most Common SAFIs used today listed below: <AFI/SAFI> IPv4 Unicast <1/1>, IPv6 Unicast <2/1>, VPN-IPV4 <1/128>, VPN-IPV6 <2/128>, Multicasat VPN <1/129>, Multicasat VPN <2/129>,BGP-LU IPV4 (GRT) <1/4>

________ IPv4-Only _____ / \ IPv4-Only PE / CE / \__/ \___ PE / CE +----+ +----+ / \ +------+ +-----+ | | | | | |_ | | | | | | | | | \ | | | | | CE |--| PE |--\ IPv4-Only Core |----| PE |---| CE | | | | | \0=========Underlay =======0| | | | | +----+ +----+ \ __/ +------+ +-----+ IPv4 BGP peer \ MPLS / SR domain / IPv4 BGP peer IPv4 forwarding \__ __ / IPv4 forwarding IPv6 forwarding \_______/ \_____/ IPv6 forwarding

________ IPv4-Only _____ / \ IPv4-Only PE / CE / \__/ \___ PE / CE +----+ +----+ / \ +------+ +-----+ | | | | | 0====VPN Overlay Tunnel ==0| | | | | | | | | | \ | | | | | CE |--| PE |--\ IPv4-Only Core |----| PE |---| CE | | | | | \0=========Underlay =======0| | | | | +----+ +----+ \ __/ +------+ +-----+ IPv4 BGP peer \ MPLS / SR domain / IPv4 BGP peer IPv4 forwarding \__ __ / IPv4 forwarding IPv6 forwarding \_______/ \_____/ IPv6 forwarding Huawei: Edge and Core-VRPv8, Release VRP-V800R020C10

________ IPv4-Only _____ / \ IPv4-Only PE / CE / \__/ \___ PE / CE +----+ +----+ / \ +------+ +-----+ | | | | | 0====VPN Overlay Tunnel ==0| | | | | | | | | | \ | | | | | CE |--| PE |--\ IPv4-Only Core |----| PE |---| CE | | | | | \0=========Underlay =======0| | | | | +----+ +----+ \ __/ +------+ +-----+ IPv4 BGP peer \ MPLS / SR domain / IPv4 BGP peer IPv4 forwarding \__ __ / IPv4 forwarding IPv6 forwarding \_______/ \_____/ IPv6 forwarding

Inter-AS ASBR-ASBR link is IPv6-Only PE IPv6-Only __________ __________ IPv6-Only PE / CE / \ / \ PE / CE +--+ +----+ / \ / \ +--+ +--+ | | | | | AS 1 \ | AS 2 \ | | | | | | | | | \IPv6| \ | | | | |CE|-| PE |--| IPv4-Only Core|----|IPv4-Only Core|--|PE|-|CE| | | | | |0=Overlay===0 | |0==Overlay===0| | | | | +--+ +----+ \ / \ / +--+ +--+ IPv6 BGP peer \ MPLS/SR / \ MPLS/SR / IPv6 BGP peer IPv4 forwarding \_________/ \_________/ IPv4 forwarding IPv6 forwarding IPv6 forwarding

Inter-AS ASBR-ASBR link is IPv6-Only PE IPv6-Only __________ __________ IPv6-Only PE / CE / \ / \ PE / CE +--+ +----+ / \ / \ +--+ +--+ | | | | | AS 1 \ | AS 2 \ | | | | | | | | | \IPv6| \ | | | | |CE|-| PE |--| IPv6-Only Core|----|IPv6-Only Core|--|PE|-|CE| | | | | |0=Underlay==0 | |0==Underlay==0| | | | | +--+ +----+ \ / \ / +--+ +--+ IPv6 BGP peer \ MPLS/SR / \ MPLS/SR / IPv6 BGP peer IPv4 forwarding \_________/ \_________/ IPv4 forwarding IPv6 forwarding IPv6 forwarding

Inter-AS ASBR-ASBR link is IPv6-Only PE IPv6-Only __________ __________ IPv6-Only PE / CE / \ / \ PE / CE +--+ +----+ / \ / \ +--+ +--+ | | | | | AS 1 \ | AS 2 \ | | | | | | | | | \IPv6| \ | | | | |CE|-| PE |--| IPv6-Only Core|--- |IPv6-Only Core|--|PE|-|CE| | | | | |0=Underlay==0 | |0==Underlay==0| | | | | +--+ +----+ \ / \ / +--+ +--+ IPv6 BGP peer \ MPLS/SR / \ MPLS/SR / IPv6 BGP peer IPv4 forwarding \_________/ \_________/ IPv4 forwarding IPv6 forwarding IPv6 forwarding

Inter-AS ASBR-ASBR link is IPv6-Only PE IPv6-Only __________ __________ IPv6-Only PE / CE / \ / \ PE / CE +--+ +----+ / \ / \ +--+ +--+ | | | | | AS 1 \ | AS 2 \ | | | | | | | | | \IPv6| \ | | | | |CE|-| PE |--| IPv6-Only Core|--- |IPv6-Only Core|--|PE|-|CE| | | | | |0=Overlay===0 | |0==Overlay===0| | | | | +--+ +----+ \ / \ / +--+ +--+ IPv6 BGP peer \ MPLS/SR / \ MPLS/SR / IPv6 BGP peer IPv4 forwarding \_________/ \_________/ IPv4 forwarding IPv6 forwarding IPv6 forwarding

Ping CE to PE when destination prefix is withdrawn Traceroute CE to PE and test all ICMPv4 and ICMPv6 type codes +-------+ +-------+ | | IPv4 Only | | | CE |----------------| PE | | | IPv4 BGP Peer | | +-------+ +-------+ IPv4 forwarding IPv4 forwarding IPv6 forwarding IPv6 forwarding

SRv6 applicability to IPv6-Only PE design SRv6 Full 128 bit SID and SRv6 Compression C-SID Next C-SID (uSID) endpoint flavor and Replace SID C-SID (G-SID) endpoint flavor is fully supported for all 12 IPv6-Only PE Design use cases. SRv6 Next SID utilizes a Next C-SID uSID carrier for the micro sid for up to 5 hops of steering without requiring an SRH. SRv6 Next SID uN Node sid endpoint function for uSID F3216 format shift 16 bits and forward to the next node allows the vanilla IPv6 data plane to be used to seamlessly stitch. across inter-as inter domain hops. The following SRv6 Compression C-SID Next C-SID (uSID) endpoint flavor 4 use cases will be fully tested by Cisco, Juniper, Nokia. 1. Global Table 4PE Test Scenario Global Table IPv6 Only PE Design where Inter-AS PE-PE core boundary AFI/SAFI 1/1 IPv4 Unicast 2/1 IPv6 Unicast (4PE) and are carried over a single IPv6 peering. In this use case the Inter-AS PE-PE nodes are SRv6 Next SID endpoint behavior capable and perform the steering function Un endpoint behavior shift 16 bits and forward function. This SRv6 compression use case is applicable to IPv6 Only PE Design Test-9 - IPv6 Core 4PE Global table BGP overlay stitching in SRv6 terms is Next Hop Unchanged Global BGP overlay stitching. Use case where Inter-AS PE-PE Edge boundary AFI/SAFI 1/1 IPv4 Unicast 2/1 IPv6 Unicast are carried over a single IPv6 peer the peering. SRv6 Test Scenarios (Global) 1. SRv6 enabled on inter-as PE-PE nodes (SRv6 aware inter domain SRv6 fabric stitching and active traffic steering) 2. SRv6 disabled on inter-as PE-PE nodes (SRv6 unaware inter domain IPv6 Data plane stitching without traffic steering) 2. VPN Overlay Test Scenario VPN Overlay IPv6 Only PE Design where Inter-AS PE-PE core boundary AFI/SAFI 1/128 IPv4 VPN 2/128 IPv6 VPN and are carried over a single IPv6 peering. In this use case the Inter-AS PE-PE nodes are SRv6 Next SID endpoint behavior capable and perform the steering function Un endpoint behavior shift 16 bits and forward function. This SRv6 compression use case is applicable to IPv6 Only PE Design Test-11 - IPv6 Core L3 VPN Inter-AS Option B which in SRv6 terms is Next Hop Unchanged VPN overlay stitching. Use case where Inter-AS PE-PE Edge boundary AFI/SAFI 1/128 IPv4 VPN 2/128 IPv6 VPN are carried over a single IPv6 peering. SRv6 Test Scenarios (IP VPN) 1. SRv6 enabled on inter-as PE-PE nodes (SRv6 aware inter domain SRv6 fabric stitching and active traffic steering) 2. SRv6 disabled on inter-as PE-PE nodes (SRv6 unaware inter domain IPv6 Data plane stitching without traffic steering)

Typed SAFI are Not Applicable to this specification Typed SAFI are SAFI where the SAFI uses the Route Types in which case their is a NLRI "Route Type" field followd by NLRI Data field containing the IPv4 and IPv6 NLRI With Non Typed SAFI the IPv4 and IPv6 NLRI is encoded directly within the NLRI making it directly data plane dependent with CP-DP control plane RIB programming followed by data plane FIB programming. This Typed SAFI case exists where the control plane procedures exist in which case the data plane is instantiated making the IPv4 and IPv6 NLRI for the Typed SAFI data plane agnostic. IPv4 Only PE deisgn has a single IPv4 Peer that carries the IPv4 and IPv6 NLRI and the interface only has an IPv4 address and requires a vendor specific knob for ipv6 forwarding. IPv6 Only PE deisgn has a single IPv6 Peer that carries the IPv4 and IPv6 NLRI and the interface only has an IPv6 address and requires a vendor specific knob for ipv4 forwarding. Since typed routes are data plane agnostic and so are not directly correlated to the IPv4 and IPv6 protocol forwarding makes the Typed SAFI listed below not applicable to this specification. The following AFI/SAFI are not applicable (N/A) to this specification 1. MCAST-VPN 2. MCAST-VPLS 3. EVPN 4. BGP-LS

With a single IPv4 Peer or IPv6 Peer carrying both IPv4 and IPv6 NLRI there are some operational considerations in terms of what changes and what does not change. What does not change with a single IPv6 transport peer carrying IPv4 NLRI and IPv6 NLRI below: Routing Policy configuration is still separate for IPv4 and IPv6 configured by capability as previously. Layer 1, Layer 2 issues such as one-way fiber or fiber cut will impact both IPv4 and IPv6 as previously. If the interface is in the Admin Down state, the IPv6 peer would go down, and IPv4 NLRI and IPv6 NLRI would be withdrawn as previously. Changes resulting from a single IPv6 transport peer carrying IPv4 NLRI and IPv6 NLRI below: Physical interface is no longer dual stacked. Any change in IPv6 address or DAD state will impact both IPv4 and IPv6 NLRI exchange. Single BFD session for both IPv4 and IPv6 NLRI fate sharing as the session is now tied to the transport, which now is only IPv6 address family. Both IPv4 and IPv6 peer now exists under the IPv6 address family configuration. Fate sharing of IPv4 and IPv6 address family from a logical perspective now carried over a single physical IPv6 peer. From an operations perspective, prior to elimination of IPv4 peers, an audit is recommended to identify and IPv4 and IPv6 peering incongruencies that may exist and to rectify them. No operational impacts or issues are expected with this change. With MPLS VPN overlay, per-CE next-hop label allcoation mode where both IPv4 and IPv6 prefixes have the same label in no table lookup pop-n-forward mode should be taken into consideration.

New IANA capability codepoint is requested for next hop encoding for IPv4 next hop applicable to all SAFI for IPv4-Only PE design Inter-AS scenarios PE-PE, PE-CE as well as existing Intra-AS PE-RR peering Scenarios.

The extensions defined in this document allow BGP to propagate reachability information about IPv4 prefixes over an MPLS or SR IPv6-Only core network. As such, no new security issues are raised beyond those that already exist in BGP-4 and the use of MP-BGP for IPv6. Both IPv4 and IPv6 peers exist under the IPv6 address family configuration. The security features of BGP and corresponding security policy defined in the ISP domain are applicable. For the inter-AS distribution of IPv6 routes according to case (a) of Section 4 of this document, no new security issues are raised beyond those that already exist in the use of eBGP for IPv6 .

Thanks to Kaliraj Vairavakkalai, Linda Dunbar, Aijun Wang, Eduardfor Vasilenko, Joel Harlpern, Michael McBride, Ketan Talaulikar for review comments.

The following people contributed substantive text to this document:

&RFC2119; &RFC2545; &RFC4291; &RFC4364; &RFC4760; &RFC5492; &RFC8174; &RFC8277; &RFC7267; &RFC9012; &RFC7117; &RFC9015; &RFC4761; &RFC6037; &RFC5747; &RFC5195; &RFC7432; &RFC7752; &RFC8955; &RFC8986; &I-D.ietf-bess-ipv6-only-pe-design; &I-D.nalawade-kapoor-tunnel-safi; &I-D.ietf-l3vpn-bgpvpn-auto; &I-D.ietf-idr-bgp-car; &I-D.mpmz-bess-mup-safi; &I-D.ietf-bess-bgp-multicast; &I-D.ietf-idr-flowspec-nvo3; &I-D.ietf-idr-sdwan-edge-discovery; &I-D.ietf-idr-segment-routing-te-policy; &I-D.ietf-lsvr-bgp-spf; &I-D.ietf-idr-rpd; &I-D.ietf-spring-srv6-srh-compression; &I-D.ietf-idr-dynamic-cap; &RFC4659; &RFC4684; &RFC4798; &RFC4925; &RFC8126; &RFC5549; &RFC5565; &RFC6074; &RFC6513; &RFC6514; &RFC8950;

IPv4-Only PE Design and IPv6-Only PE Design listing of PE-CE Edge ALL applicable SAFI. Here we showing the catagorization grouping by columns of the SAFI into 2 use case categories. Unicst Multicast IPv4-Only PE DESIGN and IPv6-Only PE DESIGN ALL SAFI's PE-CE Edge Scenario

SAFI Value	Description	Unicast	Multicast
1	Unicast	Yes	No
2	Multicast	No	Yes
78	MCAST-TREE SAFI	No	Yes

IPv4-Only PE design supports 25 / 32 IANA SAFI's of which the 7 not supported do not use AFI=1 IPv4 or AFI=2 IPv6.

IPv4-Only PE Design and IPv6-Only PE Design listing of Inter-AS PE-PE ALL applicable SAFI. All Typed SAFI are listed as Not Applicable (N/A) Here we show the catagorization grouping by columns of the SAFI into 5 use case categories. Unicst Multicast L1-L2 VPN Tunnel BGP Policy IPv4-Only PE DESIGN and IPv6-Only PE Design ALL SAFI's Inter-AS PE-PE Scenario

SAFI Value	Description	Unicast	Multicast	L1-L2 VPN	Tunnel	BGP Policy
1	NLRI Unicast	Yes	No	No	No	No
2	NLRI Multicast	No	Yes	No	No	No
4	NLRI MPLS Laels	Yes	No	No	No	No
5	MCAST-VPN	No	Yes	No	No	No
6	Dynamic Multi Segment PW	No	No	Yes	No	No
8	MCAST-VPLS	N/A	N/A	N/A	N/A	N/A
9	BGP-SFC	No	No	No	No	No
64	Tunnel SAFI	No	No	No	Yes	No
65	VPLS	No	No	No	No	No
66	BGP MDT SAFI	NO	Yes	No	No	No
67	BGP 4to6 SAFI	No	No	No	Yes	No
68	BGP 6to4 SAFI	No	No	No	Yes	No
69	L1 VPN Auto Discovery	No	No	Yes	No	No
70	BGP EVPN	N/A	N/A	N/A	N/A	N/A
71	BGP-LS	N/A	N/A	N/A	N/A	N/A
72	BGP-LS-VPN	N/A	N/A	N/A	N/A	N/A
73	SR-TE Policy SAFI	No	No	No	No	Yes
74	SD-WAN Capabilities	No	No	No	No	Yes
75	Routing Policy SAFI	No	No	No	No	No
77	Tunneled Traffic Flowspec	No	No	No	Yes	No
78	MCAST-TREE SAFI	No	Yes	No	No	No
80	BGP-LS-SPF	No	No	No	No	No
83	BGP CAR	N/A	N/A	N/A	N/A	N/A
84	BGP CAR VPN	N/A	N/A	N/A	N/A	N/A
85	BGP MUP SAFI	No	No	No	No	Yes
128	MPLS VPN	Yes	No	No	No	No
129	MPLS Multicast VPN	N/A	N/A	N/A	N/A	N/A
132	Route Target Constrains	Yes	No	No	No	No
133	Dissemination of Flowspec Rules	No	No	No	No	Yes
134	L3VPN Dissemination of Flowspec Rules	No	No	No	No	Yes
140	VPN Auto Discovery	No	No	No	No	Yes

IPv4-Only PE Design and IPv6-Only PE design supports 20 / 32 IANA SAFI's of which the 7 not supported do not use AFI=1 IPv4 or AFI=2 IPv6 and 5 are N/A.