Deployment Guidelines for Edge Peering IPv4-NLRI with IPv6-NH
draft-ietf-bess-deployment-guide-ipv4nlri-ipv6nh-00
The information below is for an old version of the document.
| Document | Type |
This is an older version of an Internet-Draft whose latest revision state is "Replaced".
|
|
|---|---|---|---|
| Authors | Gyan Mishra , Mankamana Prasad Mishra , Jeff Tantsura , Lili Wang , Qing Yang , Adam Simpson , Shuanglong Chen | ||
| Last updated | 2021-05-10 | ||
| Replaced by | draft-ietf-bess-ipv6-only-pe-design | ||
| RFC stream | Internet Engineering Task Force (IETF) | ||
| Formats | |||
| Additional resources | Mailing list discussion | ||
| Stream | WG state | WG Document | |
| Document shepherd | (None) | ||
| IESG | IESG state | I-D Exists | |
| Consensus boilerplate | Unknown | ||
| Telechat date | (None) | ||
| Responsible AD | (None) | ||
| Send notices to | (None) |
draft-ietf-bess-deployment-guide-ipv4nlri-ipv6nh-00
BESS Working Group G. Mishra
Internet-Draft Verizon Inc.
Intended status: Best Current Practice M. Mishra
Expires: November 7, 2021 Cisco Systems
J. Tantsura
L. Wang
Juniper Networks, Inc.
Q. Yang
Arista Networks
A. Simpson
Nokia
S. Chen
Huawei Technologies
May 6, 2021
Deployment Guidelines for Edge Peering IPv4-NLRI with IPv6-NH
draft-ietf-bess-deployment-guide-ipv4nlri-ipv6nh-00
Abstract
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) Edge network from IPv4
to IPv6. Operators must be able to continue to support IPv4
customers when both the Core and Edge networks are IPv6-Only.
This document details an important External BGP (eBGP) PE-CE Edge
IPv6-Only peering design that leverages the MP-BGP capability
exchange by using IPv6 peering as pure transport, allowing both 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. The design change provides the
same Dual Stacking functionality that exists today with separate IPv4
and IPv6 BGP sessions as we have today. With this design change from
a control plane perspective a single IPv6 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 and CE interface
for both IPv4 and IPv6 packet forwarding.
This document provides a much needed solution for Internet Exchange
Point (IXP) that are facing IPv4 address depletion at large peering
points. With this design, IXP can now deploy PE-CE IPv6-Only eBGP
Edge peering design to eliminate IPv4 provisioning at the Edge. This
core and edge IPv6-Only peering design paradigm change 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
Mishra, et al. Expires November 7, 2021 [Page 1]
Internet-Draft IPv4 NLRI IPv6NH May 2021
eBGP peering scenario. This document provides interoperability test
cases for the IPv6-Only peering design as well as test results
between five major vendors stakeholders in the routing and switching
indusrty, Cisco, Juniper, Arista, 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 Current Practice for
eBGP IPv6-Only Edge peering.
As this issue with IXP IPv4 address depletion is a critical issue
around the world, it is imperative for an immediate solution that can
be implemented quickly. This Best Current Practice IPv6-only eBGP
peering design specification will help proliferate IPv6-Only
deployments at the eBGP Edge network peering points to starting
immediately at a minimum with operators around the world using Cisco,
Juniper, Arista, Nokia and Huawei. As other vendors start to
implement this Best Current Practice, the IXP IPv4 address depletion
gap will eventually be eliminated.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on November 7, 2021.
Copyright Notice
Copyright (c) 2021 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(https://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of
Mishra, et al. Expires November 7, 2021 [Page 2]
Internet-Draft IPv4 NLRI IPv6NH May 2021
the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Requirements Language . . . . . . . . . . . . . . . . . . . . 5
3. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 6
4. IPv6-Only Edge Peering Architecture . . . . . . . . . . . . . 6
4.1. Problem Statement . . . . . . . . . . . . . . . . . . . . 6
4.2. IPv6-Only PE-CE Design Solution . . . . . . . . . . . . . 7
4.3. IPv6-Only Edge Peering Design . . . . . . . . . . . . . . 8
4.3.1. IPv6-Only Edge Peering Packet Walk . . . . . . . . . 8
4.3.2. 6to4 Softwire IPv4-Only Core packet walk . . . . . . 9
4.3.3. 4to6 Softwire IPv6-Only Core packet walk . . . . . . 10
4.4. RFC5549 and RFC8950 Applicability . . . . . . . . . . . . 13
4.4.1. IPv6-Only Edge Peering design next-hop encoding . . . 13
4.4.2. RFC8950 updates to RFC5549 applicability . . . . . . 13
5. IPv6-Only Design Edge E2E Test Cases . . . . . . . . . . . . 14
5.1. Test-1 IPv6-Only PE-CE Global Table over IPv4-Only Core . 14
5.2. Test-2 E2E IPv6-Only PE-CE VPN over IPv4-Only Core . . . 15
5.3. Test-3 IPv6-Only PE-CE Global Table over IPv6-Only Core . 15
5.4. Test-4 IPv6-Only PE-CE VPN over IPv6-Only Core . . . . . 16
5.5. IPv6-Only PE-CE Operational Considerations Testing . . . 16
6. Operational Considerations . . . . . . . . . . . . . . . . . 17
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 18
8. Security Considerations . . . . . . . . . . . . . . . . . . . 18
9. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 18
10. References . . . . . . . . . . . . . . . . . . . . . . . . . 18
10.1. Normative References . . . . . . . . . . . . . . . . . . 18
10.2. Informative References . . . . . . . . . . . . . . . . . 19
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 20
1. Introduction
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. Operators have a
requirement to support IPv4 customers and must be able to support
IPv4 address family and Sub-Address-Family Virtual Private Network
(VPN)-IPv4, and Multicast VPN IPv4 customers.
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
Mishra, et al. Expires November 7, 2021 [Page 3]
Internet-Draft IPv4 NLRI IPv6NH May 2021
this IPv6-only BGP peering design, only IPv6 is configured on the PE-
CE interface, the Provider Edge (PE) - Customer Edge (CE), 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 [RFC8950], while continuing to forward both IPv4 and IPv6
packets. In the framework of this design the PE is no longer Dual
Stacked. However in the case of the CE, PE-CE link CE side of the
link is no longer Dual Stacked, however all other internal links
within the CE domain may or maynot be Dual stacked.
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. [RFC8950] 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. [RFC8950] 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.
The current specification for carrying IPv4 NLRI of a given address
family via a Next Hop of a different address family is now defined in
[RFC8950], and specifies the extended next hop encoding MP-REACH
capability extension necessary to do so. This comprises an extension
of the AFI/SAFI definitions to allow the address of the Next Hop for
IPv4 NLRI or VPN-IPv4 NLRI to belong to either the IPv4 or the IPv6
protocol, the encoding of the Next Hop information to determine which
of the protocols the address belongs to, and a new BGP Capability
allowing MP-BGP peers to dynamically discover whether they can
exchange IPv4 NLRI and VPN- IPv4 NLRI with an IPv6 Next Hop.
With the new extensions defined in [RFC8950] 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-
CE peering point, and now enable the peering to be IPv6-ONLY. The
elimination of IPv4 on the PE-CE 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
Mishra, et al. Expires November 7, 2021 [Page 4]
Internet-Draft IPv4 NLRI IPv6NH May 2021
of both IPv4 and IPv6 BGP peers. This reduction decreases the number
of PE-CE BGP peers by fifty percent, which is a tremendous cost
savings for operators.
While the savings exists at the Edge eBGP PE-CE peering, on the core
side 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 and thus can only have
an IPv6 peer and must use [RFC8950] extended next hop encoding to
carrying IPv4 NLRI IPV4 <2/1>, VPN-IPV4 <2/128>, and Multicasat VPN
<2/129> over an IPv6 next hop.
This document provides a much needed solution for Internet Exchange
Point (IXP) that are facing IPv4 address depletion at large peering
points. With this design, IXP can now use deploy PE-CE IPv6-Only
eBGP Edge peering design to eliminate IPv4 provisioning at the Edge.
This core and edge IPv6-Only peering design paradigm change 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. This document provides interoperability test
cases for the IPv6-Only peering design as well as successful test
results between five major vendors stakeholders in the routing and
switching indusrty, Cisco, Juniper, Arista, 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.
As this issue with IXP address depletion is a critical issue around
the world, it is imperative for an immediate solution that can be
implemented quickly. This best practice IPv6-only eBGP peering
design specification will help proliferate IPv6-Only deployments at
the eBGP Edge network peering points starting immediately at a
minimum with operators around the world using Cisco, Juniper, Arista,
Nokia and Huawei.
2. Requirements Language
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 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
Mishra, et al. Expires November 7, 2021 [Page 5]
Internet-Draft IPv4 NLRI IPv6NH May 2021
3. Terminology
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
4. IPv6-Only Edge Peering Architecture
4.1. Problem Statement
This specification addresses a real issue that has been discussed at
many operator groups around the world related to IXP major peering
points where hundreds of AS's have both IPv4 and IPv6 dual stacked
peering. IPv4 address depletion have been a major issue issue for
many years now. Operators around the world are clamoring for a
solution that can help solve issues related to IPv4 address depletion
at these large IXP peering points. With this solution IXPs as well
as all 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 IPv4 address space saving.
IXP Problem Statement
Dual Stacked Dual Stacked
CE PE
+-------+ IPv4 BGP Peer +-------+
| |---------------| |
| CE | IPv6 BGP Peer | PE |
| |---------------| |
+-------+ +-------+
IPv4 forwarding IPv4 forwarding
IPv6 forwarding IPv6 forwarding
Figure 1: Problem Statement - IXP Dual Stack Peering
Mishra, et al. Expires November 7, 2021 [Page 6]
Internet-Draft IPv4 NLRI IPv6NH May 2021
________
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
Figure 2: Problem Statement - E2E Dual Stack Edge
4.2. IPv6-Only PE-CE Design Solution
The IPv6-Only Edge design solution provides a means of E2E single
protocol design solution extension of [RFC5565] Softwire Mesh
framework from the PE-CE Edge to the Core from ingres so egress
through the entire operators domain. This solution eliminates all
IPv4 addressing from end to end while still providing the same Dual
Stack functionality of IPv4 and IPv6 packet forwarding from a data
plane perspective by leveraging the [RFC8950] extended next hop
encoding so that IPv4 NLRI can be advertised over a single IPv6 pure
transport TCP session. This IPv6-Only E2E architecture eliminates
all IPv4 peering and IPv4 addressing E2E from the ingress CE to
ingress PE to egress PE to egress CE and all hops along the operator
E2E path.
Solution applicable to
any Edge peering scenario - IXP, Core, DC, Access, etc
+-------+ +-------+
| | IPv6 Only | |
| CE |----------------| PE |
| | IPv6 BGP Peer | |
+-------+ +-------+
IPv4 forwarding IPv4 forwarding
IPv6 forwarding IPv6 forwarding
Figure 3: IPv6-Only Solution Applicability
Mishra, et al. Expires November 7, 2021 [Page 7]
Internet-Draft IPv4 NLRI IPv6NH May 2021
________
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 \IP / MPLS / SR domain / IPv6 BGP peer
IPv4 forwarding \__ __ / IPv4 forwarding
IPv6 forwarding \_______/ \_____/ IPv6 forwarding
Figure 4: E2E VPN Solution
4.3. IPv6-Only Edge Peering Design
4.3.1. IPv6-Only Edge Peering Packet Walk
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.
Mishra, et al. Expires November 7, 2021 [Page 8]
Internet-Draft IPv4 NLRI IPv6NH May 2021
4.3.2. 6to4 Softwire IPv4-Only Core packet walk
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.
Mishra, et al. Expires November 7, 2021 [Page 9]
Internet-Draft IPv4 NLRI IPv6NH May 2021
+--------+ +--------+
| 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|
+--------+ +--------+
Figure 5: 6to4 Softwire - IPv6 Edge over an IPv4-Only Core
4.3.3. 4to6 Softwire IPv6-Only Core packet walk
4to6 softwire where IPv6-Edge eBGP IPv6 peering where IPv4 packets at
network Edge traverse a IPv6-Only Core
Mishra, et al. Expires November 7, 2021 [Page 10]
Internet-Draft IPv4 NLRI IPv6NH May 2021
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.
Mishra, et al. Expires November 7, 2021 [Page 11]
Internet-Draft IPv4 NLRI IPv6NH May 2021
+--------+ +--------+
| 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|
+--------+ +--------+
Figure 6: 4to6 Softwire - IPv4 Edge over an IPv6-Only Core
Mishra, et al. Expires November 7, 2021 [Page 12]
Internet-Draft IPv4 NLRI IPv6NH May 2021
4.4. RFC5549 and RFC8950 Applicability
4.4.1. IPv6-Only Edge Peering design next-hop encoding
This section describes [RFC8950] next hop encoding updates to
[RFC5549] applicability to this specification. IPv6-only eBGP Edge
PE-CE peering to carry IPv4 Unicast NLRI <AFI/SAFI> IPv4 <1/1> over
an IPv6 next hop BGP capability extended hop encoding IANA capability
codepoint value 5 defined is applicable to both [RFC5549] and
[RFC8950] as IPv4 Unicast NLRI <AFI/SAFI> IPv4 <1/1> does not change
in the RFC updates.
IPv4 packets over an IPv6-Only core 4to6 Softwire E2E packet flow is
part of the IPv6-Only design vendor interoperaiblity test cases and
in that respect is applicable as [RFC8950] updates [RFC5549] for
<AFI/SAFI> VPN-IPV4 <1/128>, and Multicasat VPN <1/129>
4.4.2. RFC8950 updates to RFC5549 applicability
This section describes the [RFC8950] next hop encoding updates to
[RFC5549]
In [RFC5549] when AFI/SAFI 1/128 is used, the next-hop address is
encoded as an IPv6 address with a length of 16 or 32 bytes. This
document modifies how the next-hop address is encoded to accommodate
all existing implementations and bring consistency with VPNv4oIPv4
and VPNv6oIPv6. The next-hop address is now encoded as a VPN-IPv6
address with a length of 24 or 48 bytes [RFC8950] (see Sections 3 and
6.2 of this document). This change addresses Erratum ID 5253
(Err5253). As all known and deployed implementations are
interoperable today and use the new proposed encoding, the change
does not break existing interoperability. Updates to [RFC8950] is
applicable to the IPv6-Only PE-CE edge design for the IPv6 next hop
encoding E2E test case of IPv4 packets over and IPv6-Only core 4to6
Softwire. In this test case IPv4 Unicast NLRI <AFI/SAFI> IPv4 <1/1>
is advertised over the PE to RR core peering 4to6 softwire in <AFI/
SAFI> VPN-IPV4 <1/128>. In this test case label allocation mode
comes into play which is discussed in section 8.9.
[RFC5549] next hop encoding of MP_REACH_NLRI with:
o NLRI= NLRI as per current AFI/SAFI definition
Advertising with [RFC4760] MP_REACH_NLRI with:
o AFI = 1
o SAFI = 128 or 129
Mishra, et al. Expires November 7, 2021 [Page 13]
Internet-Draft IPv4 NLRI IPv6NH May 2021
o Length of Next Hop Address = 16 or 32
o NLRI= NLRI as per current AFI/SAFI definition
[RFC8950] next hop encoding of MP_REACH_NLRI with:
o NLRI= NLRI as per current AFI/SAFI definition
Advertising with [RFC4760] MP_REACH_NLRI with:
o AFI = 1
o SAFI = 128 or 129
o Length of Next Hop Address = 24 or 48
o Next Hop Address = VPN-IPv6 address of next hop with an 8-octet RD
set to zero (potentially followed by the link-local VPN-IPv6
address of the next hop with an 8-octet RD is set to zero).
o NLRI= NLRI as per current AFI/SAFI definition
5. IPv6-Only Design Edge E2E Test Cases
Proof of conept interoperability testing of the 4 test cases between
the 5 vendors Cisco, Juniper, Arista, Nokia and Huawei.
5.1. Test-1 IPv6-Only PE-CE Global Table over IPv4-Only Core
________
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
Figure 7: Test-1 E2E IPv6-Only PE-CE Global Table 6to4 Softwire
Mishra, et al. Expires November 7, 2021 [Page 14]
Internet-Draft IPv4 NLRI IPv6NH May 2021
Cisco, Juniper, Arista, Nokia, Huawei Test case Results documented
here.
5.2. Test-2 E2E IPv6-Only PE-CE VPN over IPv4-Only Core
________
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
Figure 8: Test-2 E2E IPv6-Only PE-CE Design VPN 6to4 Softwire
Cisco, Juniper, Arista, Nokia, Huawei Test case Results documented
here.
5.3. Test-3 IPv6-Only PE-CE Global Table over IPv6-Only Core
________
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
Figure 9: Test-3 E2E IPv6-Only PE-CE Global Table 4to6 Softwire
Mishra, et al. Expires November 7, 2021 [Page 15]
Internet-Draft IPv4 NLRI IPv6NH May 2021
Cisco, Juniper, Arista, Nokia, Huawei Test case Results documented
here.
5.4. Test-4 IPv6-Only PE-CE VPN over IPv6-Only Core
________
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
Figure 10: Test-4 E2E IPv6-Only PE-CE VPN 4to6 Softwire
Cisco, Juniper, Arista, Nokia, Huawei Test case Results documented
here.
5.5. IPv6-Only PE-CE Operational Considerations Testing
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
Figure 11: Ping and Trace Test Case
Cisco, Juniper, Arista, Nokia, Huawei Test case Results documented
here.
Mishra, et al. Expires November 7, 2021 [Page 16]
Internet-Draft IPv4 NLRI IPv6NH May 2021
6. Operational Considerations
With a single 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.
Mishra, et al. Expires November 7, 2021 [Page 17]
Internet-Draft IPv4 NLRI IPv6NH May 2021
7. IANA Considerations
There are not any IANA considerations.
8. Security Considerations
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 [RFC2545].
9. Acknowledgments
Thanks to Kaliraj Vairavakkalai, Linda Dunbar, Aijun Wang, Eduardfor
Vasilenko, Joel Harlpern, Michael McBride, Ketan Talaulikar for
review comments.
10. References
10.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>.
[RFC2545] Marques, P. and F. Dupont, "Use of BGP-4 Multiprotocol
Extensions for IPv6 Inter-Domain Routing", RFC 2545,
DOI 10.17487/RFC2545, March 1999,
<https://www.rfc-editor.org/info/rfc2545>.
[RFC4291] Hinden, R. and S. Deering, "IP Version 6 Addressing
Architecture", RFC 4291, DOI 10.17487/RFC4291, February
2006, <https://www.rfc-editor.org/info/rfc4291>.
[RFC4364] Rosen, E. and Y. Rekhter, "BGP/MPLS IP Virtual Private
Networks (VPNs)", RFC 4364, DOI 10.17487/RFC4364, February
2006, <https://www.rfc-editor.org/info/rfc4364>.
Mishra, et al. Expires November 7, 2021 [Page 18]
Internet-Draft IPv4 NLRI IPv6NH May 2021
[RFC4760] Bates, T., Chandra, R., Katz, D., and Y. Rekhter,
"Multiprotocol Extensions for BGP-4", RFC 4760,
DOI 10.17487/RFC4760, January 2007,
<https://www.rfc-editor.org/info/rfc4760>.
[RFC5492] Scudder, J. and R. Chandra, "Capabilities Advertisement
with BGP-4", RFC 5492, DOI 10.17487/RFC5492, February
2009, <https://www.rfc-editor.org/info/rfc5492>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>.
[RFC8277] Rosen, E., "Using BGP to Bind MPLS Labels to Address
Prefixes", RFC 8277, DOI 10.17487/RFC8277, October 2017,
<https://www.rfc-editor.org/info/rfc8277>.
10.2. Informative References
[I-D.ietf-idr-dynamic-cap]
Ramachandra, S. and E. Chen, "Dynamic Capability for BGP-
4", draft-ietf-idr-dynamic-cap-14 (work in progress),
December 2011.
[RFC4659] De Clercq, J., Ooms, D., Carugi, M., and F. Le Faucheur,
"BGP-MPLS IP Virtual Private Network (VPN) Extension for
IPv6 VPN", RFC 4659, DOI 10.17487/RFC4659, September 2006,
<https://www.rfc-editor.org/info/rfc4659>.
[RFC4684] Marques, P., Bonica, R., Fang, L., Martini, L., Raszuk,
R., Patel, K., and J. Guichard, "Constrained Route
Distribution for Border Gateway Protocol/MultiProtocol
Label Switching (BGP/MPLS) Internet Protocol (IP) Virtual
Private Networks (VPNs)", RFC 4684, DOI 10.17487/RFC4684,
November 2006, <https://www.rfc-editor.org/info/rfc4684>.
[RFC4798] De Clercq, J., Ooms, D., Prevost, S., and F. Le Faucheur,
"Connecting IPv6 Islands over IPv4 MPLS Using IPv6
Provider Edge Routers (6PE)", RFC 4798,
DOI 10.17487/RFC4798, February 2007,
<https://www.rfc-editor.org/info/rfc4798>.
[RFC4925] Li, X., Ed., Dawkins, S., Ed., Ward, D., Ed., and A.
Durand, Ed., "Softwire Problem Statement", RFC 4925,
DOI 10.17487/RFC4925, July 2007,
<https://www.rfc-editor.org/info/rfc4925>.
Mishra, et al. Expires November 7, 2021 [Page 19]
Internet-Draft IPv4 NLRI IPv6NH May 2021
[RFC5549] Le Faucheur, F. and E. Rosen, "Advertising IPv4 Network
Layer Reachability Information with an IPv6 Next Hop",
RFC 5549, DOI 10.17487/RFC5549, May 2009,
<https://www.rfc-editor.org/info/rfc5549>.
[RFC5565] Wu, J., Cui, Y., Metz, C., and E. Rosen, "Softwire Mesh
Framework", RFC 5565, DOI 10.17487/RFC5565, June 2009,
<https://www.rfc-editor.org/info/rfc5565>.
[RFC6074] Rosen, E., Davie, B., Radoaca, V., and W. Luo,
"Provisioning, Auto-Discovery, and Signaling in Layer 2
Virtual Private Networks (L2VPNs)", RFC 6074,
DOI 10.17487/RFC6074, January 2011,
<https://www.rfc-editor.org/info/rfc6074>.
[RFC6513] Rosen, E., Ed. and R. Aggarwal, Ed., "Multicast in MPLS/
BGP IP VPNs", RFC 6513, DOI 10.17487/RFC6513, February
2012, <https://www.rfc-editor.org/info/rfc6513>.
[RFC6514] Aggarwal, R., Rosen, E., Morin, T., and Y. Rekhter, "BGP
Encodings and Procedures for Multicast in MPLS/BGP IP
VPNs", RFC 6514, DOI 10.17487/RFC6514, February 2012,
<https://www.rfc-editor.org/info/rfc6514>.
[RFC8126] Cotton, M., Leiba, B., and T. Narten, "Guidelines for
Writing an IANA Considerations Section in RFCs", BCP 26,
RFC 8126, DOI 10.17487/RFC8126, June 2017,
<https://www.rfc-editor.org/info/rfc8126>.
[RFC8950] Litkowski, S., Agrawal, S., Ananthamurthy, K., and K.
Patel, "Advertising IPv4 Network Layer Reachability
Information (NLRI) with an IPv6 Next Hop", RFC 8950,
DOI 10.17487/RFC8950, November 2020,
<https://www.rfc-editor.org/info/rfc8950>.
Authors' Addresses
Gyan Mishra
Verizon Inc.
Email: gyan.s.mishra@verizon.com
Mishra, et al. Expires November 7, 2021 [Page 20]
Internet-Draft IPv4 NLRI IPv6NH May 2021
Mankamana Mishra
Cisco Systems
821 Alder Drive,
MILPITAS CALIFORNIA 95035
Email: mankamis@cisco.com
Jeff Tantsura
Juniper Networks, Inc.
Email: jefftant.ietf@gmail.com
Lili Wang
Juniper Networks, Inc.
10 Technology Park Drive,
Westford MA 01886
US
Email: liliw@juniper.net
Qing Yang
Arista Networks
Email: qyang@arista.com
Adam Simpson
Nokia
Email: adam.1.simpson@nokia.com
Shuanglong Chen
Huawei Technologies
Email: chenshuanglong@huawei.com
Mishra, et al. Expires November 7, 2021 [Page 21]