draft-ietf-bess-ir-05.txt   rfc7988.txt 
BESS Working Group E. Rosen, Ed. Internet Engineering Task Force (IETF) E. Rosen, Ed.
Internet-Draft Juniper Networks, Inc. Request for Comments: 7988 Juniper Networks, Inc.
Updates: 6513,6514 (if approved) K. Subramanian Updates: 6513, 6514 K. Subramanian
Intended status: Standards Track Sproute Networks Category: Standards Track Sproute Networks
Expires: February 16, 2017 Z. Zhang ISSN: 2070-1721 Z. Zhang
Juniper Networks, Inc. Juniper Networks, Inc.
August 15, 2016 October 2016
Ingress Replication Tunnels in Multicast VPN Ingress Replication Tunnels in Multicast VPN
draft-ietf-bess-ir-05
Abstract Abstract
RFCs 6513, 6514, and other RFCs describe procedures by which a RFCs 6513, 6514, and other RFCs describe procedures by which a
Service Provider may offer Multicast VPN service to its customers. Service Provider may offer Multicast VPN (MVPN) service to its
These procedures create point-to-multipoint (P2MP) or multipoint-to- customers. These procedures create point-to-multipoint (P2MP) or
multipoint trees across the Service Provider's backbone. One type of multipoint-to-multipoint (MP2MP) trees across the Service Provider's
P2MP tree that may be used is known as an "Ingress Replication (IR) backbone. One type of P2MP tree that may be used is known as an
tunnel". In an IR tunnel, a parent node need not be "directly "Ingress Replication (IR) tunnel". In an IR tunnel, a parent node
connected" to its child nodes. When a parent node has to send a need not be directly connected to its child nodes. When a parent
multicast data packet to its child nodes, it does not use layer 2 node has to send a multicast data packet to its n child nodes, it
multicast, IP multicast, or MPLS multicast to do so. Rather, it does not use Layer 2 multicast, IP multicast, or MPLS multicast to do
makes n individual copies, and then unicasts each copy, through an IP so. Rather, it makes n individual copies, and then unicasts each
or MPLS unicast tunnel, to exactly one child node. While the prior copy, through an IP or MPLS unicast tunnel, to exactly one child
MVPN specifications allow the use of IR tunnels, those specifications node. While the prior MVPN specifications allow the use of IR
are not always very clear or explicit about how the MVPN protocol tunnels, those specifications are not always very clear or explicit
elements and procedures are applied to IR tunnels. This document about how the MVPN protocol elements and procedures are applied to IR
updates RFCs 6513 and 6514 by adding additional details that are tunnels. This document updates RFCs 6513 and 6514 by adding
specific to the use of IR tunnels. additional details that are specific to the use of IR tunnels.
Status of This Memo Status of This Memo
This Internet-Draft is submitted in full conformance with the This is an Internet Standards Track document.
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 http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months This document is a product of the Internet Engineering Task Force
and may be updated, replaced, or obsoleted by other documents at any (IETF). It represents the consensus of the IETF community. It has
time. It is inappropriate to use Internet-Drafts as reference received public review and has been approved for publication by the
material or to cite them other than as "work in progress." Internet Engineering Steering Group (IESG). Further information on
Internet Standards is available in Section 2 of RFC 7841.
This Internet-Draft will expire on February 16, 2017. Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
http://www.rfc-editor.org/info/rfc7988.
Copyright Notice Copyright Notice
Copyright (c) 2016 IETF Trust and the persons identified as the Copyright (c) 2016 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of (http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License. described in the Simplified BSD License.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. What is an IR P-tunnel? . . . . . . . . . . . . . . . . . . . 5 2. What is an IR P-tunnel? . . . . . . . . . . . . . . . . . . . 5
3. How are IR P-tunnels Identified? . . . . . . . . . . . . . . 7 3. How are IR P-tunnels identified? . . . . . . . . . . . . . . 7
4. How to Join an IR P-tunnel . . . . . . . . . . . . . . . . . 9 4. How to Join an IR P-Tunnel . . . . . . . . . . . . . . . . . 9
4.1. Advertised IR P-tunnels . . . . . . . . . . . . . . . . . 9 4.1. Advertised IR P-Tunnels . . . . . . . . . . . . . . . . . 9
4.1.1. If the 'Leaf Info Required Bit' is Set . . . . . . . 10 4.1.1. If the Leaf Information Required Bit Is Set . . . . . 10
4.1.2. If the 'Leaf Info Required Bit' is Not Set . . . . . 10 4.1.2. If the Leaf Information Required Bit Is Not Set . . . 10
4.2. Unadvertised IR P-tunnels . . . . . . . . . . . . . . . . 11 4.2. Unadvertised IR P-Tunnels . . . . . . . . . . . . . . . . 11
5. The PTA's 'Tunnel Identifier' Field . . . . . . . . . . . . . 11 5. The PTA's Tunnel Identifier Field . . . . . . . . . . . . . . 11
6. A Note on IR P-tunnels and 'Discarding Packets from the Wrong 6. A Note on IR P-Tunnels and Discarding Packets from the Wrong
PE' . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 PE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
7. The PTA's 'MPLS Label' Field . . . . . . . . . . . . . . . . 13 7. The PTA's MPLS Label Field . . . . . . . . . . . . . . . . . 14
7.1. Leaf A-D Route Originated by an Egress PE . . . . . . . . 14 7.1. Leaf A-D Route Originated by an Egress PE . . . . . . . . 14
7.2. Leaf A-D Route Originated by an Intermediate Node . . . . 16 7.2. Leaf A-D Route Originated by an Intermediate Node . . . . 16
7.3. Intra-AS I-PMSI A-D Route . . . . . . . . . . . . . . . . 17 7.3. Intra-AS I-PMSI A-D Route . . . . . . . . . . . . . . . . 17
8. How A Child Node Prunes Itself from an IR P-tunnel . . . . . 17 8. How A Child Node Prunes Itself from an IR P-Tunnel . . . . . 17
9. Parent Node Actions Upon Receiving Leaf A-D Route . . . . . . 18 9. Parent Node Actions upon Receiving Leaf A-D Route . . . . . . 18
10. Use of Timers when Switching UMH . . . . . . . . . . . . . . 19 10. Use of Timers When Switching UMH . . . . . . . . . . . . . . 19
11. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 20 11. Security Considerations . . . . . . . . . . . . . . . . . . . 20
12. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 20 12. References . . . . . . . . . . . . . . . . . . . . . . . . . 21
13. Security Considerations . . . . . . . . . . . . . . . . . . . 20 12.1. Normative References . . . . . . . . . . . . . . . . . . 21
14. References . . . . . . . . . . . . . . . . . . . . . . . . . 20 12.2. Informative References . . . . . . . . . . . . . . . . . 21
14.1. Normative References . . . . . . . . . . . . . . . . . . 20 Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 23
14.2. Informative References . . . . . . . . . . . . . . . . . 21 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 23
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 22
1. Introduction 1. Introduction
RFCs 6513, 6514, and others describe procedures by which a Service RFCs 6513, 6514, and other RFCs describe procedures by which a
Provider (SP) may offer Multicast VPN (MVPN) service to its Service Provider (SP) may offer Multicast VPN (MVPN) service to its
customers. These procedures create point-to-multipoint (P2MP) or customers. These procedures create point-to-multipoint (P2MP) or
multipoint-to-multipoint (MP2MP) tunnels, called "P-tunnels" multipoint-to-multipoint (MP2MP) tunnels, called "P-tunnels"
(Provider-tunnels), across the SP's backbone network. Customer (provider tunnels), across the SP's backbone network. Customer
multicast traffic is carried through the P-tunnels. multicast traffic is carried through the P-tunnels.
A number of different P-tunnel technologies are supported. One of A number of different P-tunnel technologies are supported. One of
the supported P-tunnel technologies is known as "ingress replication" the supported P-tunnel technologies is known as "ingress replication"
or "unicast replication". We will use the acronym "IR" to refer to or "unicast replication". We will use the acronym "IR" to refer to
this P-tunnel technology. this P-tunnel technology.
An IR P-tunnel is a P2MP tree, but a given node on the tree is not An IR P-tunnel is a P2MP tree, but a given node on the tree is not
necessarily "directly attached" to its parent node or to its child necessarily directly attached to its parent node or to its child
nodes. To send a multicast data packet from a parent node to one of nodes. To send a multicast data packet from a parent node to one of
its child nodes, the parent node encapsulates the packet and then its child nodes, the parent node encapsulates the packet and then
unicasts it through a tunnel to the child node. The tunnel may be a unicasts it through a tunnel to the child node. The tunnel may be a
P2P (point-to-point) or MP2P (multipoint-to-point) MPLS LSP (label P2P or MP2P MPLS LSP (Label Switched Path) or a unicast IP tunnel.
switched path) or a unicast IP tunnel. If a node on an IR tree has n If a node on an IR tree has n child nodes, and has a multicast data
child nodes, and has a multicast data packet that must be sent along packet that must be sent along the tree, the parent node makes n
the tree, the parent node makes n individual copies of the data individual copies of the data packet, and then sends each copy,
packet, and then sends each copy, through a unicast tunnel, to through a unicast tunnel, to exactly one child node. No lower-layer
exactly one child node. No lower layer multicast technology is used multicast technology is used when sending traffic from a parent node
when sending traffic from a parent node to a child node; multiple to a child node; therefore, multiple copies of the packet may be sent
copies of the packet may therefore be sent out a single interface. out a single interface.
With the single exception of IR, the P-tunnel technologies supported With the single exception of IR, the P-tunnel technologies supported
by the MVPN specifications are pre-existing IP multicast or MPLS by the MVPN specifications are preexisting IP multicast or MPLS
multicast technologies. Each such technology has its own set of multicast technologies. Each such technology has its own set of
specifications, its own setup and maintenance protocols, its own specifications, its own setup and maintenance protocols, its own
syntax for identifying specific multicast trees, and its own syntax for identifying specific multicast trees, and its own
procedures for enabling a router to be added to or removed from a procedures for enabling a router to be added to or removed from a
particular multicast tree. For IR P-tunnels, on the other hand, particular multicast tree. For IR P-tunnels, on the other hand,
there is no prior specification for setting up and maintaining the there is no prior specification for setting up and maintaining the
P2MP trees; the procedures and protocol elements used for setting up P2MP trees; the procedures and protocol elements used for setting up
and maintaining the P2MP trees are specified in the MVPN and maintaining the P2MP trees are specified in the MVPN
specifications themselves, and all the signaling/setup is done by specifications themselves, and all the signaling/setup is done by
using the BGP A-D (Auto-Discovery) routes that are defined in using the BGP Auto-Discovery (A-D) routes that are defined in
[RFC6514]. (The unicast tunnels used to transmit multicast data from [RFC6514]. (The unicast tunnels used to transmit multicast data from
one node to another in an IR P-tunnel may of course have their own one node to another in an IR P-tunnel may of course have their own
setup and maintenance protocols, e.g., [RFC5036], [RFC3209].) setup and maintenance protocols, e.g., [RFC5036], [RFC3209].)
Since the transmission of a multicast data packet along an IR Since the transmission of a multicast data packet along an IR
P-tunnel is done by transmitting the packet through a unicast tunnel, P-tunnel is done by transmitting the packet through a unicast tunnel,
previous RFCs sometimes speak of an IR P-tunnel as "consisting of" a previous RFCs sometimes describe an IR P-tunnel as "consisting of" a
set of unicast tunnels. However, that way of speaking is not quite set of unicast tunnels. However, that description is not quite
accurate. For one thing, it obscures the fact that an IR P-tunnel is accurate. For one thing, it obscures the fact that an IR P-tunnel is
really a P2MP tree, whose nodes must maintain multicast state in both really a P2MP tree, whose nodes must maintain multicast state in both
the control and data planes. For another, it obscures the fact the the control and data planes. For another, it obscures the fact the
unicast tunnels used by a particular IR P-tunnel need not be specific unicast tunnels used by a particular IR P-tunnel need not be specific
to that P-tunnel; a single unicast tunnel can carry the multicast to that P-tunnel; a single unicast tunnel can carry the multicast
traffic of many different IR P-tunnels (and can also carry unicast traffic of many different IR P-tunnels (and can also carry unicast
traffic as well). traffic as well).
In this document, we provide a clearer and more explicit conceptual In this document, we provide a clearer and more explicit conceptual
model for IR P-tunnels, clarifying the relationship between an IR model for IR P-tunnels, clarifying the relationship between an IR
P-tunnel and the unicast tunnels that are used for data transmission P-tunnel and the unicast tunnels that are used for data transmission
along the IR P-tunnel. along the IR P-tunnel.
Section 5 of [RFC6514] defines a BGP Path Attribute known as the Section 5 of [RFC6514] defines a BGP Path Attribute known as the
"PMSI (Provider Multicast Service Interface) Tunnel attribute" (PTA). "PMSI (Provider Multicast Service Interface) Tunnel attribute" (PTA).
This attribute contains a field known as the "Tunnel Identifier" This attribute contains a field known as the "Tunnel Identifier"
field. For most P-tunnel technologies, the PTA's "Tunnel Identifier" field. For most P-tunnel technologies, the PTA's "Tunnel Identifier"
field is used to identify a P-tunnel (i.e., to identify a P2MP or field is used to identify a P-tunnel (i.e., to identify a P2MP or
MP2MP tree). However, when IR P-tunnels are used, the PTA "Tunnel MP2MP tree). However, when IR P-tunnels are used, the PTA "Tunnel
Identifier" field does not actually identify an IR P-tunnel. In some Identifier" field does not actually identify an IR P-tunnel. In some
cases it identifies one of the P-tunnel's constituent unicast cases, it identifies one of the P-tunnel's constituent unicast
tunnels, and in other cases it is not used to identify a tunnel at tunnels; in other cases, it is not used to identify a tunnel at all.
all. In this document, we provide an explicit specification for how In this document, we provide an explicit specification for how IR
IR P-tunnels are actually identified. P-tunnels are actually identified.
Some of the MVPN specifications use phrases like "join the identified Some of the MVPN specifications specify procedures that require a PE
P-tunnel", even though there has up to now not been an explicit router to join the P-tunnel that has been identified in a particular
MVPN route. However, up to now, there has not been an explicit
specification of how to identify an IR P-tunnel, of how a router specification of how to identify an IR P-tunnel, of how a router
joins such a P-tunnel, or of how a router prunes itself from such a joins such a P-tunnel, or of how a router prunes itself from such a
P-tunnel. In this document, we make these procedures more explicit. P-tunnel. In this document, we make these procedures more explicit.
[RFC6514] does provide a method for binding an MPLS label to a [RFC6514] does provide a method for binding an MPLS label to a
P-tunnel, but does not discuss the label allocation policies that are P-tunnel, but does not discuss the label allocation policies that are
needed for correct operation when the P-tunnel is an IR P-tunnel. needed for correct operation when the P-tunnel is an IR P-tunnel.
Those policies are discussed in this document. Those policies are discussed in this document.
This document does not provide any new protocol elements, or any This document does not provide any new protocol elements or any
fundamentally new procedures; its purpose is to make explicit just fundamentally new procedures; its purpose is to make explicit just
how a router is to use the protocol elements and procedures of how a router is to use the protocol elements and procedures of
[RFC6513] and [RFC6514] to identify an IR P-tunnel, to join an IR [RFC6513] and [RFC6514] to identify an IR P-tunnel, to join an IR
P-tunnel, and to prune itself from an IR P-tunnel. P-tunnel, and to prune itself from an IR P-tunnel.
This document also discusses the MPLS label allocation policies that This document also discusses the MPLS label allocation policies that
need to be supported when binding MPLS labels to IR P-tunnels, and need to be supported when binding MPLS labels to IR P-tunnels, and
the timer policies that need to be supported when switching a the timer policies that need to be supported when switching a
customer multicast flow from one IR P-tunnel to another. These are customer multicast flow from one IR P-tunnel to another. These are
procedures that are not clearly specified in [RFC6513] or [RFC6514]. procedures that are not clearly specified in [RFC6513] or [RFC6514].
skipping to change at page 4, line 51 skipping to change at page 5, line 4
fundamentally new procedures; its purpose is to make explicit just fundamentally new procedures; its purpose is to make explicit just
how a router is to use the protocol elements and procedures of how a router is to use the protocol elements and procedures of
[RFC6513] and [RFC6514] to identify an IR P-tunnel, to join an IR [RFC6513] and [RFC6514] to identify an IR P-tunnel, to join an IR
P-tunnel, and to prune itself from an IR P-tunnel. P-tunnel, and to prune itself from an IR P-tunnel.
This document also discusses the MPLS label allocation policies that This document also discusses the MPLS label allocation policies that
need to be supported when binding MPLS labels to IR P-tunnels, and need to be supported when binding MPLS labels to IR P-tunnels, and
the timer policies that need to be supported when switching a the timer policies that need to be supported when switching a
customer multicast flow from one IR P-tunnel to another. These are customer multicast flow from one IR P-tunnel to another. These are
procedures that are not clearly specified in [RFC6513] or [RFC6514]. procedures that are not clearly specified in [RFC6513] or [RFC6514].
As the material in this document must be understood in order to As the material in this document must be understood in order to
properly implement IR P-tunnels, this document is considered to properly implement IR P-tunnels, this document updates [RFC6513] and
update [RFC6513] and [RFC6514]. [RFC6514].
This document also discusses the application of "seamless multicast" This document also discusses the application of "seamless multicast"
[RFC7524] and "extranet" [RFC7900] procedures to IR P-tunnels. [RFC7524] and "extranet" [RFC7900] procedures to IR P-tunnels.
This draft does not discuss the use of IR P-tunnels to support a VPN This document does not discuss the use of IR P-tunnels to support a
customer's use of Bidirectional Protocol Independent Multicast VPN customer's use of Bidirectional Protocol Independent Multicast
(BIDIR-PIM). [RFC7740] explains how to adapt the procedures of (BIDIR-PIM). [RFC7740] explains how to adapt the procedures of
[RFC6513], [RFC6514], and [RFC7582] so that a customer's use of [RFC6513], [RFC6514], and [RFC7582] so that a customer's use of
BIDIR-PIM can be supported by IR P-tunnels. BIDIR-PIM can be supported by IR P-tunnels.
In the event of any conflict between this document and either In the event of any conflict between this document and either
[RFC6513] or [RFC6514], this document takes precedence. [RFC6513] or [RFC6514], this document takes precedence.
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL", when and only when appearing in all capital letters, are "OPTIONAL", when and only when appearing in all capital letters, are
skipping to change at page 6, line 6 skipping to change at page 6, line 10
In a segmented P-tunnel, IR may be used for some or all of the In a segmented P-tunnel, IR may be used for some or all of the
segments. If a particular segment of a segmented P-tunnel uses IR, segments. If a particular segment of a segmented P-tunnel uses IR,
then the root of that segment may have child nodes that are ABRs or then the root of that segment may have child nodes that are ABRs or
ASBRs, rather than egress PEs. ASBRs, rather than egress PEs.
As with any type of P2MP tree, each node of an IR P-tunnel holds As with any type of P2MP tree, each node of an IR P-tunnel holds
"multicast state" for the P-tunnel. That is, each node knows the "multicast state" for the P-tunnel. That is, each node knows the
identity of its parent node on the tree, and each node knows the identity of its parent node on the tree, and each node knows the
identities of its child nodes on the tree. In the MVPN specs, the identities of its child nodes on the tree. In the MVPN specs, the
"parent" node is also known as the "Upstream Multicast Hop" or "UMH". "parent" node is also known as the "Upstream Multicast Hop" or "UMH".
Note that the "UMH" may be a PE, an ASBR, or (if procedures from Note that the UMH may be a PE, an ASBR, or (if procedures from
[RFC7524] are being used) an ABR. (In [RFC7524], the term "upstream [RFC7524] are being used) an ABR. (In [RFC7524], the term "upstream
node" is used instead of "UMH".) node" is used instead of "UMH".)
What distinguishes an IR P-tunnel from any other kind of P2MP tree is What distinguishes an IR P-tunnel from any other kind of P2MP tree is
the method by which a data packet is transmitted from a parent node the method by which a data packet is transmitted from a parent node
to a child node. To transmit a multicast data packet from a parent to a child node. To transmit a multicast data packet from a parent
node to a child node along a particular IR P-tunnel, the parent node node to a child node along a particular IR P-tunnel, the parent node
does the following: does the following:
o It labels the packet with a label (call it a "P-tunnel label") o It labels the packet with a label (call it a "P-tunnel label")
that the child node has assigned to that P-tunnel, that the child node has assigned to that P-tunnel.
o It then places the packet in a unicast encapsulation and unicasts o It then places the packet in a unicast encapsulation and unicasts
the packet to the child node. That is, the parent node sends the the packet to the child node. That is, the parent node sends the
packet through a "unicast tunnel" to a particular child node. packet through a unicast tunnel to a particular child node. This
This unicast tunnel need not be specially created to be part of unicast tunnel need not be specially created to be part of the IR
the IR P-tunnel; it can be any P2P or MP2P unicast tunnel that P-tunnel; it can be any P2P or MP2P unicast tunnel that will get
will get the packets from the parent node to the child node. A the packets from the parent node to the child node. A single such
single such unicast tunnel may be carrying multicast data packets unicast tunnel may be carrying multicast data packets of several
of several different P2MP trees, and may also be carrying unicast different P2MP trees and may also be carrying unicast data
data packets. packets.
The parent node repeats this process for each child node, creating The parent node repeats this process for each child node, creating
one copy for each child node, and sending each copy through a unicast one copy for each child node, and sending each copy through a unicast
tunnel to corresponding child node. It does not use layer 2 tunnel to corresponding child node. It does not use Layer 2
multicast, IP multicast, or MPLS multicast to transmit packets to its multicast, IP multicast, or MPLS multicast to transmit packets to its
child nodes. As a result, multiple copies of each packet may be sent child nodes. As a result, multiple copies of each packet may be sent
out a single interface; this may happen, e.g., if that interface is out a single interface; this may happen, e.g., if that interface is
the next hop interface, according to unicast routing, from the parent the next-hop interface, according to unicast routing, from the parent
node to several of the child nodes. node to several of the child nodes.
Since data traveling along an IR P-tunnel is always unicast from Since data traveling along an IR P-tunnel is always unicast from
parent node to child node, it can be convenient to think of an IR parent node to child node, it can be convenient to think of an IR
P-tunnel as a P2MP tree whose arcs are unicast tunnels. However, it P-tunnel as a P2MP tree whose arcs are unicast tunnels. However, it
is important to understand that the unicast tunnels need not be is important to understand that the unicast tunnels need not be
specific to any particular IR P-tunnel. If R1 is the parent node of specific to any particular IR P-tunnel. If R1 is the parent node of
R2 on two different IR P-tunnels, a single unicast tunnel from R1 to R2 on two different IR P-tunnels, a single unicast tunnel from R1 to
R2 may be used to carry data along both IR P-tunnels. All that is R2 may be used to carry data along both IR P-tunnels. All that is
required is that when the data packets arrive at R2, R2 will see the required is that when the data packets arrive at R2, R2 will see the
"P-tunnel label" at the top of the packets' label stack; R2's further "P-tunnel label" at the top of the packets' label stack; R2's further
processing of the packets will depend upon that label. Note that the processing of the packets will depend upon that label. Note that the
same unicast tunnel between R1 and R2 may also be carrying unicast same unicast tunnel between R1 and R2 may also be carrying unicast
data packets. data packets.
Typically the unicast tunnels are the Label Switched Paths (LSPs) Typically, the unicast tunnels are the LSPs that already exist to
that already exist to carry unicast traffic; either MP2P LSPs created carry unicast traffic; either MP2P LSPs created by the Label
by LDP (Label Distribution Protocol, [RFC5036]) or P2P LSPs created Distribution Protocol (LDP) [RFC5036] or P2P LSPs created by Resource
by RSVP-TE (Resource Reservation Protocol - Traffic Engineering, Reservation Protocol - Traffic Engineering (RSVP-TE) [RFC3209].
[RFC3209]). However, any other kind of unicast tunnel may be used. However, any other kind of unicast tunnel may be used. A unicast
A unicast tunnel may have an arbitrary number of intermediate tunnel may have an arbitrary number of intermediate routers; those
routers; those routers do not maintain any multicast state for the IR routers do not maintain any multicast state for the IR P-tunnel and,
P-tunnel, and in general are not even aware of its existence. in general, are not even aware of its existence.
As with all other P-tunnel types, an IR P-tunnel may be used to As with all other P-tunnel types, an IR P-tunnel may be used to
instantiate either an Inclusive PMSI or a Selective PMSI. See instantiate either an Inclusive PMSI (I-PMSI) or a Selective PMSI
Section 3.2 of [RFC6513] for an explanation of those concepts. (S-PMSI). See Section 3.2 of [RFC6513] for an explanation of those
concepts.
3. How are IR P-tunnels Identified? 3. How are IR P-tunnels identified?
There are four MVPN BGP route types in which P-tunnels can be There are four MVPN BGP route types in which P-tunnels can be
identified: Intra-AS I-PMSI A-D (Intra Autonomous System Inclusive identified: Intra-AS I-PMSI A-D routes, Inter-AS I-PMSI A-D routes,
PMSI A-D) routes, Inter-AS I-PMSI A-D routes, S-PMSI (Selective PMSI) S-PMSI A-D routes, and Leaf A-D routes. (These route types are all
A-D routes, and Leaf A-D routes. (These route types are all defined defined in [RFC6514]).
in [RFC6514]).
Whenever it is necessary to identify a P-tunnel in a route of one of Whenever it is necessary to identify a P-tunnel in a route of one of
these types, a "PMSI Tunnel Attribute" (PTA) is added to the route. these types, a "PMSI Tunnel Attribute" (PTA) is added to the route.
As defined in [RFC6514] section 5, the PTA contains four fields: As defined in Section 5 of [RFC6514], the PTA contains four fields:
"Tunnel Type", "MPLS Label", "Tunnel Identifier", and "Flags". Tunnel Type, MPLS Label, Tunnel Identifier, and Flags. [RFC6514]
[RFC6514] defines only one bit in the "Flags" field, the "Leaf defines only one bit in the Flags field, the Leaf Information
Information Required" bit. Required bit.
If a route identifies an IR P-tunnel, the "Tunnel Type" field of its If a route identifies an IR P-tunnel, the Tunnel Type field of its
PTA is set to the value 6, meaning "Ingress Replication". PTA is set to the value 6, meaning "Ingress Replication".
Most types of P-tunnel are associated with specific protocols that Most types of P-tunnel are associated with specific protocols that
are used to set up and maintain tunnels of that type. For example, are used to set up and maintain tunnels of that type. For example,
if the "Tunnel Type" field is set to 2, meaning "mLDP P2MP LSP", the if the Tunnel Type field is set to 2, meaning "mLDP P2MP LSP", the
associated setup protocol is mLDP [RFC6388]. The associated setup associated setup protocol is Multipoint LDP (mLDP) [RFC6388]. The
protocol always has a method of identifying the tunnels that it sets associated setup protocol always has a method of identifying the
up. For example, mLDP uses a "FEC element" (Forwarding Equivalence tunnels that it sets up. For example, mLDP uses an FEC element
Class Element) to identify a tree. If the "Tunnel type" field is set (Forwarding Equivalence Class element) to identify a tree. If the
to 3, meaning "PIM SSM Tree" (Protocol Independent Multicast Source- Tunnel Type field is set to 3, meaning "PIM-SSM Tree", where "SSM"
Specific Tree), the associated setup protocol is PIM, and "(S,G)" is stands for Source-Specific Multicast, the associated setup protocol
used to identify the tree. In these cases, the "Tunnel Identifier" is PIM, and "(S,G)" is used to identify the tree. In these cases,
field of the PTA carries a tree identifier as defined by the setup the Tunnel Identifier field of the PTA carries a tree identifier as
protocol used for the particular tunnel type. defined by the setup protocol used for the particular tunnel type.
IR P-tunnels, on the other hand, are entirely setup and maintained by IR P-tunnels, on the other hand, are entirely setup and maintained by
the use of BGP A-D routes, and are not associated with any other the use of BGP A-D routes and are not associated with any other setup
setup protocol. (The unicast tunnels used to transmit multicast data protocol. (The unicast tunnels used to transmit multicast data along
along an IR P-tunnel may have their own setup and maintenance an IR P-tunnel may have their own setup and maintenance protocols, of
protocols, of course.) The means of identifying a P-tunnel is very course.) The means of identifying a P-tunnel is very different for
different for IR P-tunnels than for other types of P-tunnel: IR P-tunnels than for other types of P-tunnel:
When an IR P-tunnel is identified in an S-PMSI A-D route, an When an IR P-tunnel is identified in an S-PMSI A-D route, an
Intra-AS I-PMSI A-D route, or an Inter-AS I-PMSI A-D route (we Intra-AS I-PMSI A-D route, or an Inter-AS I-PMSI A-D route (we
will refer to these three route types as "advertising A-D will refer to these three route types as "advertising A-D
routes"), its identifier is hereby defined to be the NLRI (Network routes"), its identifier is hereby defined to be the NLRI (Network
Layer Reachability Information) of that route. See sections 4.1, Layer Reachability Information) of that route. See Sections 4.1,
4.2, and 4.3 of [RFC6514] for the specification of these NLRIs. 4.2, and 4.3 of [RFC6514] for the specification of these NLRIs.
Note that the IR P-tunnel identifier includes the "route type" and Note that the IR P-tunnel identifier includes the Route Type and
"length" octets of the NLRI. Length fields (see Section 4 of [RFC6514]) of the NLRI.
To reiterate: To reiterate:
The identifier of the IR P-tunnel does not appear in the PTA at The identifier of the IR P-tunnel does not appear in the PTA at
all; the "Tunnel Identifier" field of the PTA does not contain the all; the Tunnel Identifier field of the PTA does not contain the
identifier of the IR P-tunnel. identifier of the IR P-tunnel.
Rather,the identifier of the IR P-tunnel appears in the "Network Rather, the identifier of the IR P-tunnel appears in the Network
Layer Reachability Information" (NLRI) field of the A-D routes Layer Reachability Information (NLRI) field of the A-D routes that
that are used to advertise and to setup the IR P-tunnel. are used to advertise and to setup the IR P-tunnel.
Note that an advertising A-D route is considered to identify an IR Note that an advertising A-D route is considered to identify an IR
P-tunnel only if it carries a PTA whose "Tunnel Type" field is set to P-tunnel only if it carries a PTA whose Tunnel Type field is set to
"IR". "IR".
When an IR P-tunnel is identified in an S-PMSI A-D route or in an When an IR P-tunnel is identified in an S-PMSI A-D route or in an
Inter-AS I-PMSI A-D route, the "Leaf Info Required" bit of the Flags Inter-AS I-PMSI A-D route, the Leaf Information Required bit of the
field of the PTA MUST be set. Flags field of the PTA MUST be set.
In an advertising A-D route: In an advertising A-D route:
o If the "Leaf Info Required" bit of the Flags field of the PTA is o If the Leaf Information Required bit of the Flags field of the PTA
set, then the "Tunnel Identifier" field of the PTA has no is set, then the Tunnel Identifier field of the PTA has no
significance whatsoever, and MUST be ignored upon reception. significance whatsoever and MUST be ignored upon reception.
Note that, per RFC6514, the length of the "Tunnel Identifier" Note that, per RFC 6514, the length of the Tunnel Identifier field
field of the PTA is variable, and is inferred from the length of of the PTA is variable and is inferred from the length of the PTA.
the PTA. Even when this field is of no significance, its length Even when this field is of no significance, its length MUST be the
MUST be the length of an IP address in the address space of the length of an IP address in the address space of the SP's backbone,
SP's backbone, as specified in section 4.2 of [RFC6515]. In this as specified in Section 4.2 of [RFC6515]. In this case, it is
case, it is RECOMMENDED that it be set to a routable address of RECOMMENDED that it be set to a routable address of the router
the router that constructed the PTA. (While it might make more that constructed the PTA. (While it might make more sense to
sense to allow or even require the field to be omitted entirely, allow or even require the field to be omitted entirely, that might
that might raise issues of backwards compatibility with raise issues of backwards compatibility with implementations that
implementations that were designed prior to the publication of were designed prior to the publication of this document.)
this document.)
o If the "Leaf Info Required" bit is not set, the "Tunnel o If the Leaf Information Required bit is not set, the Tunnel
Identifier" field of the PTA does have significance, but it does Identifier field of the PTA does have significance, but it does
not identify the IR P-tunnel. The use of the PTA's "Tunnel not identify the IR P-tunnel. The use of the PTA's Tunnel
Identifier" field in this case is discussed in Section 5 of this Identifier field in this case is discussed in Section 5 of this
document. document.
Note that according to the above definition, there is no way for two Note that according to the above definition, there is no way for two
different advertising A-D routes (i.e., two advertising A-D routes different advertising A-D routes (i.e., two advertising A-D routes
with different NLRIs) to advertise the same IR P-tunnel. In the with different NLRIs) to advertise the same IR P-tunnel. In the
terminology of [RFC6513], an IR P-tunnel can instantiate only a terminology of [RFC6513], an IR P-tunnel can instantiate only a
single PMSI. If an ingress PE, for example, wants to bind two single PMSI. If an ingress PE, for example, wants to bind two
customer multicast flows to a single IR P-tunnel, it must advertise customer multicast flows to a single IR P-tunnel, it must advertise
that IR P-tunnel either in an I-PMSI A-D route or in an S-PMSI A-D that IR P-tunnel either in an I-PMSI A-D route or in an S-PMSI A-D
route whose NLRI contains wildcards ([RFC6625]). route whose NLRI contains wildcards [RFC6625].
When an IR P-tunnel is identified in a Leaf A-D route, its identifier When an IR P-tunnel is identified in a Leaf A-D route, its identifier
is the "route key" field of the route's NLRI. See section 4.4 of is the Route Key field of the route's NLRI. See Section 4.4 of
[RFC6514]. [RFC6514].
A Leaf A-D route is considered to identify an IR P-tunnel only if it A Leaf A-D route is considered to identify an IR P-tunnel only if it
carries a PTA whose "Tunnel Type" field is set to "IR". In this type carries a PTA whose Tunnel Type field is set to "IR". In this type
of route, the "Tunnel Identifier" field of the PTA does have of route, the Tunnel Identifier field of the PTA does have
significance, but it does not identify the IR P-tunnel. The use of significance, but it does not identify the IR P-tunnel. The use of
the PTA's "Tunnel Identifier" field in this case is discussed in the PTA's Tunnel Identifier field in this case is discussed in
Section 5. Section 5.
4. How to Join an IR P-tunnel 4. How to Join an IR P-Tunnel
The procedures for joining an IR P-tunnel depend upon whether the The procedures for joining an IR P-tunnel depend upon whether the
P-tunnel has been previously advertised, and if so, upon how the P-tunnel has been previously advertised, and, if so, upon how the
P-tunnel was advertised. Note that joining an unadvertised IR P-tunnel was advertised. Note that joining an unadvertised IR
P-tunnel is only possible when using the "Global Table Multicast" P-tunnel is only possible when using the "global table multicast"
procedures of [RFC7524]. procedures of [RFC7524].
4.1. Advertised IR P-tunnels 4.1. Advertised IR P-tunnels
The procedures in this section apply when the IR P-tunnel to be The procedures in this section apply when the IR P-tunnel to be
joined has been advertised in an S-PMSI A-D route, an Inter-AS I-PMSI joined has been advertised in an S-PMSI A-D route, an Inter-AS I-PMSI
A-D route, or an Intra-AS I-PMSI A-D route. A-D route, or an Intra-AS I-PMSI A-D route.
The procedures for joining an advertised IR P-tunnel depend upon The procedures for joining an advertised IR P-tunnel depend upon
whether the A-D route that advertises the IR P-tunnel has the "Leaf whether the A-D route that advertises the IR P-tunnel has the Leaf
Info Required" bit set in its PTA. Information Required bit set in its PTA.
4.1.1. If the 'Leaf Info Required Bit' is Set 4.1.1. If the Leaf Information Required Bit Is Set
The procedures in this section apply when the P-tunnel to be joined The procedures in this section apply when the P-tunnel to be joined
has been advertised in a route whose PTA has the "Leaf Info Required has been advertised in a route whose PTA has the Leaf Information
Bit" set. Required bit set.
The router joining a particular IR P-tunnel must determine its UMH The router joining a particular IR P-tunnel must determine its UMH
for that P-tunnel. If the route that advertised the IR P-tunnel for that P-tunnel. If the route that advertised the IR P-tunnel
contains a P2MP Segmented Next Hop Extended Community, the UMH is contains a P2MP Segmented Next Hop Extended Community, the UMH is
determined from the value of this community (see [RFC7524]). determined from the value of this community (see [RFC7524]).
Otherwise the UMH is determined from the route's next hop (see Otherwise, the UMH is determined from the route's next hop (see
[RFC6514]). [RFC6514]).
Once the UMH is determined, the router joining the IR P-tunnel Once the UMH is determined, the router joining the IR P-tunnel
originates a Leaf A-D route. The NLRI of the Leaf A-D route is originates a Leaf A-D route. The NLRI of the Leaf A-D route is
formed following the procedures of [RFC6514]. As a result, the NLRI formed following the procedures of [RFC6514]. As a result, the NLRI
of the Leaf A-D route will contain the IR P-tunnel identifier defined of the Leaf A-D route will contain the IR P-tunnel identifier defined
in Section 3 above as its "route key". The UMH MUST be identified by in Section 3 above as its "route key". The UMH MUST be identified by
attaching an "IP Address Specific Route Target" (or an "IPv6 Address attaching an "IP-address-specific Route Target" (or an "IPv6-address-
Specific Route Target") to the Leaf A-D route. The IP address of the specific Route Target") to the Leaf A-D route. The IP address of the
UMH appears in the "global administrator" field of the Route Target UMH appears in the Global Administrator field of the Route Target
(RT). Details can be found in [RFC6514] and [RFC7524]. (RT). Details can be found in [RFC6514] and [RFC7524].
The Leaf A-D route MUST also contain a PTA whose fields are set as The Leaf A-D route MUST also contain a PTA whose fields are set as
follows: follows:
o The "Tunnel Type" field is set to "IR". o The Tunnel Type field is set to "IR".
o The "Tunnel Identifier" field is set as described in Section 5 of o The Tunnel Identifier field is set as described in Section 5 of
this document. (Note that this field does not contain the IR this document. (Note that this field does not contain the IR
P-tunnel Identifier that is defined in Section 3.) P-tunnel Identifier that is defined in Section 3.)
o The "MPLS Label" field is set to a non-zero value. This is the o The MPLS Label field is set to a non-zero value. This is the
"P-tunnel label". The value must be chosen so as to satisfy "P-tunnel label". The value must be chosen so as to satisfy
various constraints, as discussed in Section 7 this document. various constraints, as discussed in Section 7 this document.
4.1.2. If the 'Leaf Info Required Bit' is Not Set 4.1.2. If the Leaf Information Required Bit Is Not Set
The procedures in this section apply when the IR P-tunnel to be The procedures in this section apply when the IR P-tunnel to be
joined has been advertised in a route whose PTA does not have the joined has been advertised in a route whose PTA does not have the
"Leaf Info Required Bit" set. This can only be the case if the IR Leaf Information Required bit set. This can only be the case if the
P-tunnel was advertised in an Intra-AS I-PMSI A-D route. IR P-tunnel was advertised in an Intra-AS I-PMSI A-D route.
If an IR P-tunnel is advertised in the Intra-AS I-PMSI A-D routes If an IR P-tunnel is advertised in the Intra-AS I-PMSI A-D routes
originated by the PE routers of a given MVPN, the Intra-AS I-PMSI can originated by the PE routers of a given MVPN, the Intra-AS I-PMSI can
be thought of as being instantiated by a set of IR P-tunnels. Each be thought of as being instantiated by a set of IR P-tunnels. Each
PE is the root of one such IR P-tunnel, and the other PEs are PE is the root of one such IR P-tunnel, and the other PEs are
children of the root. A PE simultaneously joins all these P-tunnels children of the root. A PE simultaneously joins all these P-tunnels
by originating (if it hasn't already done so) an Intra-AS I-PMSI A-D by originating (if it hasn't already done so) an Intra-AS I-PMSI A-D
route with a PTA whose fields are set as follows: route with a PTA whose fields are set as follows:
o The "Tunnel Type" field is set to "IR". o The Tunnel Type field is set to "IR".
o The "Tunnel Identifier" field is set as described in Section 5 of o The Tunnel Identifier field is set as described in Section 5 of
this document. (Note that this field does not contain the IR this document. (Note that this field does not contain the IR
P-tunnel Identifier that defined in Section 3.) P-tunnel identifier that is defined in Section 3.)
o The "MPLS Label" field MUST be set to a non-zero value. This o The MPLS Label field MUST be set to a non-zero value. This label
label value will be used by the child node to associate a received value will be used by the child node to associate a received
packet with the I-PMSI of a particular MVPN. The MPLS label packet with the I-PMSI of a particular MVPN. The MPLS label
allocation policy must be such as to ensure that the binding from allocation policy must be such as to ensure that the binding from
label to I-PMSI is one-to-one. label to I-PMSI is one to one.
The NLRI and the RTs of the originated I-PMSI A-D route are set as The NLRI and the RTs of the originated I-PMSI A-D route are set as
specified in [RFC6514]. specified in [RFC6514].
4.2. Unadvertised IR P-tunnels 4.2. Unadvertised IR P-Tunnels
In [RFC7524], a procedure is defined for "Global Table Multicast", in In [RFC7524], a procedure is defined for "global table multicast", in
which a P-tunnel can be joined even if the P-tunnel has not been which a P-tunnel can be joined even if the P-tunnel has not been
previously advertised. See the sections of that document entitled previously advertised. See Sections 6.2.2 and 6.2.3 of [RFC7524]:
"Leaf A-D Route for Global Table Multicast" and "Constructing the "Leaf A-D Route for Global Table Multicast" and "Constructing the
Rest of the Leaf A-D Route". The route key of the Leaf A-D route has Rest of the Leaf A-D Route". The route key of the Leaf A-D route has
the form of the "S-PMSI Route-Type Specific NLRI" in this case, and the form of the "S-PMSI Route-Type Specific NLRI" (see Section 4.3 of
that should be considered to be the IR P-tunnel identifier. Note [RFC6514]) in this case, and that should be considered to be the IR
that the procedure for finding the UMH is different in this case; the P-tunnel identifier. Note that the procedure for finding the UMH is
UMH is the next hop of the best UMH-eligible route towards the different in this case; the UMH is the next hop of the best UMH-
"ingress PE". See the section of that document entitled "Determining eligible route towards the "ingress PE". See Section 6.1 of
the Upstream ABR/PE/ASBR (Upstream Node)". [RFC7524], entitled "Determining the Upstream ABR/PE/ASBR (Upstream
Node)".
5. The PTA's 'Tunnel Identifier' Field 5. The PTA's Tunnel Identifier Field
As discussed in Section 1, when the "Tunnel Type" field of a PTA is As discussed in Section 1, when the Tunnel Type field of a PTA is set
set to "IR", the "Tunnel Identifier" field of that PTA does not to "IR", the Tunnel Identifier field of that PTA does not contain the
contain the IR P-tunnel identifier. This section (Section 5) IR P-tunnel identifier. This section specifies the procedures for
specifies the procedures for setting the "Tunnel Identifier" field of setting the Tunnel Identifier field of the PTA when the Tunnel Type
the PTA when the "Tunnel Type" field of the PTA is set to "IR". field of the PTA is set to "IR".
If the "Tunnel Type" field of a PTA is set to "IR", its "Tunnel If the Tunnel Type field of a PTA is set to "IR", its Tunnel
Identifier" field is significant only when one of the following two Identifier field is significant only when one of the following two
conditions holds: conditions holds:
o The PTA is carried by a Leaf A-D route, or o The PTA is carried by a Leaf A-D route, or
o The "Leaf Information Required" bit of the "Flags" field of the o The Leaf Information Required bit of the Flags field of the PTA is
PTA is not set. not set.
If one of these conditions holds, then the "Tunnel Identifier" field If one of these conditions holds, then the Tunnel Identifier field
must contain a routable IP address of the originator of the route. must contain a routable IP address of the originator of the route.
(See [RFC6514] sections 9.2.3.2.1 and 9.2.3.4.1 for the detailed (See Sections 9.2.3.2.1 and 9.2.3.4.1 of [RFC6514] for the detailed
specification of the contents of this field.) This address is used specification of the contents of this field.) This address is used
by the UMH to determine the unicast tunnel that it will use in order by the UMH to determine the unicast tunnel that it will use in order
to send data, along the IR P-tunnel identified by the route key, to to send data, along the IR P-tunnel identified by the route key, to
the originator of the Leaf A-D route. the originator of the Leaf A-D route.
The means by which the unicast tunnel is determined from this IP The means by which the unicast tunnel is determined from this IP
address is outside the scope of this document. The means by which address is outside the scope of this document. The means by which
the unicast tunnel is set up and maintained is also outside the scope the unicast tunnel is set up and maintained is also outside the scope
of this document. of this document.
Section 4 of [RFC6515] MUST be applied when a PTA is carried in a Section 4 of [RFC6515] MUST be applied when a PTA is carried in a
Leaf A-D route, and describes how to determine whether the "Tunnel Leaf A-D route. It describes how to determine whether the Tunnel
Identifier" field carries an IPv4 or an IPv6 address. Identifier field carries an IPv4 or an IPv6 address.
If neither of the above conditions hold, then the "Tunnel Identifier" If neither of the above conditions hold, then the Tunnel Identifier
field is of no significance, and MUST be ignored upon reception. field is of no significance and MUST be ignored upon reception.
6. A Note on IR P-tunnels and 'Discarding Packets from the Wrong PE' 6. A Note on IR P-Tunnels and Discarding Packets from the Wrong PE
Section 9.1.1 of [RFC6513] specifies a procedure known as "Discarding Section 9.1.1 of [RFC6513] specifies a procedure known as "Discarding
Packets from the Wrong PE". When an egress PE receives a multicast Packets from the Wrong PE". When an egress PE receives a multicast
data packet, this procedure requires it to determine the packet's data packet, this procedure requires it to determine the packet's
ingress PE. ingress PE.
In this document, we assume that when a packet has reached an egress In this document, we assume that when a packet has reached an egress
PE via an IR P-tunnel, the egress PE will infer the identity of the PE via an IR P-tunnel, the egress PE will infer the identity of the
packet's ingress PE by examining the packet's P-tunnel label. packet's ingress PE by examining the packet's P-tunnel label.
skipping to change at page 13, line 25 skipping to change at page 13, line 32
o Even if the IP source address field of the encapsulating IP header o Even if the IP source address field of the encapsulating IP header
does identify the ingress PE, there is no guarantee that the IP does identify the ingress PE, there is no guarantee that the IP
source address in that header is the same as the IP address used source address in that header is the same as the IP address used
by the ingress PE for the MVPN signaling procedures. by the ingress PE for the MVPN signaling procedures.
o To apply the procedures of Section 9.1.1 of [RFC6513] when o To apply the procedures of Section 9.1.1 of [RFC6513] when
extranet functionality [RFC7900] is supported, it is necessary to extranet functionality [RFC7900] is supported, it is necessary to
infer a packet's ingress VRF (Virtual Routing and Forwarding infer a packet's ingress VRF (Virtual Routing and Forwarding
table), not merely its ingress PE. This can be inferred from the table), not merely its ingress PE. This can be inferred from the
P-tunnel label (assuming that the label is allocated following the P-tunnel label (assuming that the label is allocated following the
procedures of Section 7), but can not be inferred from the IP procedures of Section 7), but it cannot be inferred from the IP
source address of the encapsulating IP header. source address of the encapsulating IP header.
We therefore assume in this document that if the procedures of We therefore assume in this document that if the procedures of
Section 9.1.1 of [RFC6513] are to be applied to packets traveling Section 9.1.1 of [RFC6513] are to be applied to packets traveling
through IR P-tunnels, those procedures will be based on the P-tunnel through IR P-tunnels, those procedures will be based on the P-tunnel
label, even if the IR P-tunnel is using IP unicast tunnels. label, even if the IR P-tunnel is using IP unicast tunnels.
This means that if an egress PE joined a particular IR P-tunnel using This means that if an egress PE joined a particular IR P-tunnel using
the procedures of Section 4.1.2, duplicate prevention on that IR the procedures of Section 4.1.2, duplicate prevention on that IR
P-tunnel requires the use of either Single Forwarder Selection P-tunnel requires the use of either Single Forwarder Selection
([RFC6513] section 9.1.2) or native PIM procedures ([RFC6513] section (Section 9.1.2 of [RFC6513]) or native PIM procedures (Section 9.1.3
9.1.3). of [RFC6513]).
7. The PTA's 'MPLS Label' Field 7. The PTA's MPLS Label Field
When the "Tunnel Type" field of a PTA is set to "IR", the "MPLS When the Tunnel Type field of a PTA is set to "IR", the MPLS Label
Label" field is not always significant. It is significant only under field is not always significant. It is significant only under the
the following conditions: following conditions:
1. Either the PTA is being carried in a Leaf A-D route, or 1. Either the PTA is being carried in a Leaf A-D route, or
2. the "Leaf Information Required" flag of the PTA is NOT set. 2. the Leaf Information Required flag of the PTA is NOT set.
Note that the "Leaf Information Required" flag of the PTA is always Note that the Leaf Information Required flag of the PTA is always set
set when a PTA specifying an IR P-tunnel is carried in an S-PMSI A-D when a PTA specifying an IR P-tunnel is carried in an S-PMSI A-D
route or in an Inter-AS I-PMSI A-D route; thus the "MPLS Label" field route or in an Inter-AS I-PMSI A-D route; thus, the MPLS Label field
of the PTA is never significant when the PTA is carried by one of of the PTA is never significant when the PTA is carried by one of
these route types. The "MPLS Label" field is significant only when these route types. The MPLS Label field is significant only when the
the PTA appears either in a Leaf A-D route or in an Intra-AS I-PMSI PTA appears either in a Leaf A-D route or in an Intra-AS I-PMSI A-D
A-D route that does not have the "Leaf Information Required" bit set. route that does not have the Leaf Information Required bit set. In
In these cases, the MPLS label is the label that the originator of these cases, the MPLS label is the label that the originator of the
the route is assigning to the IR P-tunnel(s) identified by the route is assigning to the IR P-tunnel(s) identified by the route's
route's NLRI. (That is, the MPLS label assigned in the PTA is what NLRI. (That is, the MPLS label assigned in the PTA is what we have
we have called the "P-tunnel label".) called the "P-tunnel label".)
In those cases where the "MPLS Label" field is not significant, it In those cases where the MPLS Label field is not significant, it
SHOULD be set to zero upon transmission and MUST be ignored upon SHOULD be set to zero upon transmission and MUST be ignored upon
reception. reception.
7.1. Leaf A-D Route Originated by an Egress PE 7.1. Leaf A-D Route Originated by an Egress PE
As previously stated, when a Leaf A-D route is used to join an IR As previously stated, when a Leaf A-D route is used to join an IR
P-tunnel, the "route key" of the Leaf A-D route is the P-tunnel P-tunnel, the "route key" of the Leaf A-D route is the P-tunnel
identifier. identifier.
We now define the notion of the "root of an IR P-tunnel". We now define the notion of the "root of an IR P-tunnel".
o If the identifier of an IR P-tunnel is of the form of an S-PMSI o If the identifier of an IR P-tunnel is of the form of an S-PMSI
NLRI, the "root" of the IR P-tunnel is the router identified in NLRI, the "root" of the IR P-tunnel is the router identified in
the "Originating Router's IP Address" field of that NLRI. the Originating Router's IP Address field of that NLRI.
o If the identifier of an IR P-tunnel is of the form specified in o If the identifier of an IR P-tunnel is of the form specified in
Section "Leaf A-D Route for Global Table Multicast" of [RFC7524], Section 6.2.2 of [RFC7524] ("Leaf A-D Route for Global Table
the "root" of the IR P-tunnel is the router identified in the Multicast"), the "root" of the IR P-tunnel is the router
"Ingress PE's IP Address" field of that NLRI. identified in the Ingress PE's IP Address field of that NLRI.
o If the identifier of an IR P-tunnel is of the form of an Intra-AS o If the identifier of an IR P-tunnel is of the form of an Intra-AS
I-PMSI NLRI, the "root" of the IR P-tunnel is the router I-PMSI NLRI, the "root" of the IR P-tunnel is the router
identified in the "Originating Router's IP Address" field of that identified in the Originating Router's IP Address field of that
NLRI. NLRI.
o If the identifier of an IR P-tunnel is of the form of an Inter-AS o If the identifier of an IR P-tunnel is of the form of an Inter-AS
I-PMSI NLRI, the "root" of the IR P-tunnel is same as the I-PMSI NLRI, the "root" of the IR P-tunnel is same as the
identifier of the IR P-tunnel, i.e., the combination of an RD and identifier of the IR P-tunnel, i.e., the combination of a Route
an AS. Distinguisher (RD) and an AS.
Note that if an IR P-tunnel is segmented, the root of the IR Note that if an IR P-tunnel is segmented, the root of the IR
P-tunnel, by this definition, is actually the root of the entire P-tunnel, by this definition, is actually the root of the entire
P-tunnel, not the root of the local segment. In this case, there may P-tunnel, not the root of the local segment. In this case, there may
be segments upstream that are not themselves IR P-tunnels. However, be segments upstream that are not IR P-tunnels themselves. However,
the egress PE is aware only of the final segment of the P-tunnel, and the egress PE is aware only of the final segment of the P-tunnel, and
hence considers the P-tunnel to be an IR P-tunnel. hence considers the P-tunnel to be an IR P-tunnel.
In order to apply the procedures of RFC 6513 Section 9.1.1 In order to apply the procedures of Section 9.1.1 of RFC 6513
("Discarding Packets from Wrong PE"), the following condition MUST be ("Discarding Packets from Wrong PE"), the following condition MUST be
met by the MPLS label allocation policy: met by the MPLS label allocation policy:
Suppose an egress PE originates two Leaf A-D routes, each with a Suppose an egress PE originates two Leaf A-D routes, each with a
different route key in its NLRI, and each with a PTA specifying a different route key in its NLRI, and each with a PTA specifying a
"Tunnel Type" of "IR". Thus each of the Leaf A-D routes Tunnel Type field of "IR". Thus, each of the Leaf A-D routes
identifies a different IR P-tunnel. Suppose further that each of identifies a different IR P-tunnel. Suppose further that each of
those IR P-tunnels has a different root. Then the egress PE MUST those IR P-tunnels has a different root. Then, the egress PE MUST
NOT specify the same MPLS label in both PMSI Tunnel attributes. NOT specify the same MPLS label in both PMSI Tunnel attributes.
That is, to apply the "Discarding Packets from the Wrong PE" That is, to apply the duplicate prevention procedures (in "Discarding
duplicate prevention procedures ([RFC6513] section 9.1.1), the same Packets from Wrong PE", Section 9.1.1 of [RFC6513]), the same MPLS
MPLS label MUST NOT be assigned to two IR P-tunnels that have label MUST NOT be assigned to two IR P-tunnels that have different
different roots. roots.
If segmented P-tunnels are in use, the above rule is necessary but If segmented P-tunnels are in use, the above rule is necessary but
not sufficient to prevent a PE from forwarding duplicate data to the not sufficient to prevent a PE from forwarding duplicate data to the
CEs. For various reasons, a given egress PE or egress ABR or egress CEs. For various reasons, a given egress PE or egress ABR or egress
ASBR may decide to change its parent node, on a given segmented ASBR may decide to change its parent node, on a given segmented
P-tunnel, from one router to another. It does this by changing the P-tunnel, from one router to another. It does this by changing the
RT of the Leaf A-D route that it originated in order to join that RT of the Leaf A-D route that it originated in order to join that
P-tunnel. Once the RT is changed, there may be a period of time P-tunnel. Once the RT is changed, there may be a period of time
during which the old parent node and the new parent node are both during which the old parent node and the new parent node are both
sending data of the same multicast flow. To ensure that the egress sending data of the same multicast flow. To ensure that the egress
node not forward duplicate data, whenever the egress node changes the node not forward duplicate data, whenever the egress node changes the
RT that it attaches to a Leaf A-D route, it MUST also change the RT that it attaches to a Leaf A-D route, it MUST also change the
"MPLS Label" specified in the Leaf A-D route's PTA. This allows the "MPLS Label" specified in the Leaf A-D route's PTA. This allows the
egress router to distinguish between packets arriving on a given egress router to distinguish between packets arriving on a given
P-tunnel from the old parent and packets arriving on that same P-tunnel from the old parent and packets arriving on that same
P-tunnel from the new parent. At any given time, a router MUST P-tunnel from the new parent. At any given time, a router MUST
consider itself to have only a single parent node on a given consider itself to have only a single parent node on a given P-tunnel
P-tunnel, and MUST discard traffic that arrives on that P-tunnel from and MUST discard traffic that arrives on that P-tunnel from a
a different parent node. different parent node.
If extranet functionality [RFC7900] is not implemented in a If extranet functionality [RFC7900] is not implemented in a
particular egress PE, or if an egress PE is provisioned with the particular egress PE, or if an egress PE is provisioned with the
knowledge that extranet functionality is not needed, the PE may adopt knowledge that extranet functionality is not needed, the PE may adopt
the policy of assigning a label that is unique for the ordered triple the policy of assigning a label that is unique for the ordered triple
<root, parent node, egress VRF>. This will enable the egress PE to <root, parent node, egress VRF>. This will enable the egress PE to
apply the duplicate prevention procedures discussed above, and to apply the duplicate prevention procedures discussed above and to
determine the VRF to which an arriving packet must be directed. determine the VRF to which an arriving packet must be directed.
However, this policy is not sufficient to support the "Discard However, this policy is not sufficient to support the "Do Not Deliver
Packets from the Wrong P-tunnel" procedures that are specified in Packets from the Wrong P-tunnel" procedures that are specified in
[RFC7900]. To support those procedures, the labels specified in the Section 2.3.1 of [RFC7900]. To support those procedures, the labels
PTA of Leaf A-D routes originated by a given egress PE MUST be unique specified in the PTA of Leaf A-D routes originated by a given egress
for the ordered triple <root, root RD, parent node>, where the "root PE MUST be unique for the ordered triple <root, root RD, parent
RD" is taken from the RD field of the IR P-tunnel identifier. (All node>, where the "root RD" is taken from the RD field of the IR
forms of IR P-tunnel identifier contain an embedded "RD" field.) P-tunnel identifier. (All forms of IR P-tunnel identifier contain an
This policy is also sufficient for supporting non-extranet cases, but embedded RD field.) This policy is also sufficient for supporting
in some cases may result in the use of more labels than the policy of non-extranet cases, but, in some cases, may result in the use of more
the previous paragraph. labels than the policy of the preceding paragraph.
7.2. Leaf A-D Route Originated by an Intermediate Node 7.2. Leaf A-D Route Originated by an Intermediate Node
When a P-tunnel is segmented, there will be "intermediate nodes", When a P-tunnel is segmented, there will be "intermediate nodes",
i.e., nodes that have a parent and also have children on the i.e., nodes that have a parent and also have children on the
P-tunnel. Each intermediate node is a leaf node of an "upstream P-tunnel. Each intermediate node is a leaf node of an "upstream
segment" and a root node of one or more "downstream segments". The segment" and a root node of one or more "downstream segments". The
intermediate node needs to set up its forwarding state so that data intermediate node needs to set up its forwarding state so that data
it receives on the upstream segment gets transmitted on the proper it receives on the upstream segment gets transmitted on the proper
downstream segments. downstream segments.
If the upstream segment is instantiated by IR, the intermediate node If the upstream segment is instantiated by IR, the intermediate node
will need to originate a Leaf A-D route to join that segment, and will need to originate a Leaf A-D route to join that segment, and
will need to allocate a downstream-assigned MPLS label to advertise will need to allocate a downstream-assigned MPLS label to advertise
in the MPLS label field of the Leaf A-D route's PTA. Section 7.1 in the MPLS Label field of the Leaf A-D route's PTA. Section 7.1
specifies constraints on the label allocation policy for egress PEs; specifies constraints on the label allocation policy for egress PEs;
this section specifies constraints on the label allocation policy for this section specifies constraints on the label allocation policy for
intermediate nodes. intermediate nodes.
Suppose intermediate node N originates two Leaf A-D routes, one whose Suppose intermediate node N originates two Leaf A-D routes, one whose
route key is K1, and one whose route key is K2, where K1 != K2. The route key is K1, and one whose route key is K2, where K1 != K2. The
respective PTAs of these Leaf A-D routes MUST specify distinct non- respective PTAs of these Leaf A-D routes MUST specify distinct non-
zero MPLS labels, UNLESS the following conditions all hold: zero MPLS labels, UNLESS the following conditions all hold:
1. N's parent node for P-tunnel K1 is the same as N's parent node 1. N's parent node for P-tunnel K1 is the same as N's parent node
for P-tunnel K2. for P-tunnel K2.
2. N's forwarding state is such that any packet it receives from 2. N's forwarding state is such that any packet it receives from
P-tunnel K1 is forwarded to the exact same set of downstream P-tunnel K1 is forwarded to the exact same set of downstream
neighbors as any packet it receives from P-tunnel K2. neighbors as any packet it receives from P-tunnel K2.
3. For each downstream neighbor D to which N sends the packets it 3. For each downstream neighbor D to which N sends the packets it
receives from P-tunnels K1 and K2, N's forwarding state is such receives from P-tunnels K1 and K2, N's forwarding state is such
that it applies the exact same encapsulation to packets it that it applies the exact same encapsulation to packets it
forwards from either tunnel to D. (E.g., if N uses MPLS to forwards from either tunnel to D. (For example, if N uses MPLS
forward the packets to D, it pushes the exact same set of labels to forward the packets to D, it pushes the exact same set of
on packets from P-tunnel K1 as it pushes on packets from P-tunnel labels on packets from P-tunnel K1 as it pushes on packets from
K2.) P-tunnel K2.)
Of course, N MAY always specify distinct non-zero labels in each of Of course, N MAY always specify distinct non-zero labels in each of
the Leaf A-D routes that it originates. the Leaf A-D routes that it originates.
Note that the rules of this section apply whenever the upstream Note that the rules of this section apply whenever the upstream
P-tunnel segment is an IR P-tunnel. These rules hold whether or not P-tunnel segment is an IR P-tunnel. These rules hold whether or not
some or all of the downstream segments are other types of P-tunnels. some or all of the downstream segments are other types of P-tunnels.
If the P-tunnels from N to a particular downstream neighbor D are IR If the P-tunnels from N to a particular downstream neighbor D are IR
P-tunnels, then condition 3 above will hold with respect to D only if P-tunnels, then condition 3 above will hold with respect to D only if
skipping to change at page 17, line 27 skipping to change at page 17, line 38
o N has received and installed a Leaf A-D route from D, whose route o N has received and installed a Leaf A-D route from D, whose route
key is K2, and which carries an IP-address-specific RT identifying key is K2, and which carries an IP-address-specific RT identifying
N, N,
o Those two Leaf A-D routes specify the same MPLS label in their o Those two Leaf A-D routes specify the same MPLS label in their
respective PTAs. respective PTAs.
7.3. Intra-AS I-PMSI A-D Route 7.3. Intra-AS I-PMSI A-D Route
When a router joins a set of IR P-tunnels using the procedures of When a router joins a set of IR P-tunnels using the procedures of
Section 4.1.2 of this document, the procedures of section 9.1.1 of Section 4.1.2 of this document, the procedures of Section 9.1.1 of
[RFC6513] cannot be applied, no matter what the label allocation [RFC6513] cannot be applied, no matter what the label allocation
policy is. In this case, the ingress PE is the same as the UMH, but policy is. In this case, the ingress PE is the same as the UMH, but
it is not possible to assign a label uniquely to a particular ingress it is not possible to assign a label uniquely to a particular ingress
PE or UMH. However, the label in the MPLS label field of the PTA PE or UMH. However, the label in the MPLS Label field of the PTA
MUST NOT appear in the MPLS label field of the PTA carried by any MUST NOT appear in the MPLS Label field of the PTA carried by any
other route originated by the same router. other route originated by the same router.
8. How A Child Node Prunes Itself from an IR P-tunnel 8. How a Child Node Prunes Itself from an IR P-Tunnel
If a particular IR P-tunnel was joined via the procedures of If a particular IR P-tunnel was joined via the procedures of
Section 4.1.2 of this document, a router can prune itself from the Section 4.1.2, a router can prune itself from the P-tunnel by
P-tunnel by withdrawing the Intra-AS I-PMSI A-D route it used to join withdrawing the Intra-AS I-PMSI A-D route it used to join the
the P-tunnel. This is not usually done unless the router is removing P-tunnel. This is not usually done unless the router is removing
itself entirely from a particular MVPN. itself entirely from a particular MVPN.
The procedures in the remainder of this section apply when a router The procedures in the remainder of this section apply when a router
joined a particular IR P-tunnel by originating a Leaf A-D route (as joined a particular IR P-tunnel by originating a Leaf A-D route (as
described in Section 4.1.1 or Section 4.2 of this document). described in Sections 4.1.1 or 4.2).
If a router no longer has a need to receive any multicast data from a If a router no longer has a need to receive any multicast data from a
given IR P-tunnel, it may prune itself from the P-tunnel by given IR P-tunnel, it may prune itself from the P-tunnel by
withdrawing the Leaf A-D route it used to join the tunnel. This is withdrawing the Leaf A-D route it used to join the tunnel. This is
done, e.g., if the router no longer needs any of the flows traveling done, e.g., if the router no longer needs any of the flows traveling
over the P-tunnel, or if all the flows the router does need are being over the P-tunnel, or if all the flows the router does need are being
received over other P-tunnels. received over other P-tunnels.
A router that is attached to a particular IR P-tunnel via a A router that is attached to a particular IR P-tunnel via a
particular parent node may determine that it needs to stay joined to particular parent node may determine that it needs to stay joined to
that IR P-tunnel, but via a different parent node. This can happen, that IR P-tunnel but via a different parent node. This can happen,
for example, if there is a change in the Next Hop or the P2MP for example, if there is a change in the Next Hop or the P2MP
Segmented Next Hop Extended Community of the S-PMSI A-D route in Segmented Next-Hop Extended Community of the S-PMSI A-D route in
which that P-tunnel was advertised. In this case, the router changes which that P-tunnel was advertised. In this case, the router changes
the Route Target of the Leaf A-D route it used to join the IR the Route Target of the Leaf A-D route it used to join the IR
P-tunnel, so that the Route Target now identifies the new parent P-tunnel, so that the Route Target now identifies the new parent
node. node.
A parent node must notice when a child node has been pruned from a A parent node must notice when a child node has been pruned from a
particular tree, as this will affect the parent node's multicast data particular tree, as this will affect the parent node's multicast data
state. Note that the pruning of a child node may appear to the state. Note that the pruning of a child node may appear to the
parent node as the explicit withdrawal of a Leaf A-D route, or it may parent node as the explicit withdrawal of a Leaf A-D route, or it may
appear as a change in the Route Target of a Leaf A-D route. If the appear as a change in the Route Target of a Leaf A-D route. If the
Route Target of a particular Leaf A-D route previously identified a Route Target of a particular Leaf A-D route previously identified a
particular parent node, but changes so that it no longer does so, the particular parent node, but changes so that it no longer does so, the
effect on the multicast state of the parent node is the same as if effect on the multicast state of the parent node is the same as if
the Leaf A-D route had been explicitly withdrawn. the Leaf A-D route had been explicitly withdrawn.
9. Parent Node Actions Upon Receiving Leaf A-D Route 9. Parent Node Actions upon Receiving Leaf A-D Route
These actions are detailed in [RFC6514] and [RFC7524]. Two points of These actions are detailed in [RFC6514] and [RFC7524]. Two points of
clarification are made: clarification are made:
o If a router R1 receives and installs a Leaf A-D route originated o If a router R1 receives and installs a Leaf A-D route originated
by router R2, R1's multicast state is affected only if the Leaf by router R2, R1's multicast state is affected only if the Leaf
A-D route carries an "IP Address Specific RT" (or "IPv6 Address A-D route carries an "IP-address-specific RT" (or "IPv6-address-
Specific RT") whose "global administrator" field identifies R1. specific RT") whose Global Administrator field identifies R1.
(This is as specified in [RFC6514] and [RFC7524].) If a Leaf A-D (This is as specified in [RFC6514] and [RFC7524].) If a Leaf A-D
route's RT does not identify R1, but then changes so that it does route's RT does not identify R1, but then changes so that it does
identify R1, R1 must take the same actions it would take if the identify R1, R1 must take the same actions it would take if the
Leaf A-D route were newly received. Leaf A-D route were newly received.
o It is possible that router R1 will receive and install a Leaf A-D o It is possible that router R1 will receive and install a Leaf A-D
route originated by router R2, where: route originated by router R2, where:
* the route's RT identifies R1, * the route's RT identifies R1,
skipping to change at page 19, line 12 skipping to change at page 19, line 24
* R1 has neither originated nor installed any such S-PMSI A-D * R1 has neither originated nor installed any such S-PMSI A-D
route. route.
If at some later time, R1 installs the corresponding S-PMSI A-D If at some later time, R1 installs the corresponding S-PMSI A-D
route, and the Leaf A-D route is still installed, and the Leaf A-D route, and the Leaf A-D route is still installed, and the Leaf A-D
route's RT still identifies R1, then R1 MUST follow the same route's RT still identifies R1, then R1 MUST follow the same
procedures it would have followed if the S-PMSI A-D route had been procedures it would have followed if the S-PMSI A-D route had been
installed before the Leaf A-D route was installed. Implementers must installed before the Leaf A-D route was installed. Implementers must
not assume that events occur in the "usual" or "expected" order. not assume that events occur in the "usual" or "expected" order.
10. Use of Timers when Switching UMH 10. Use of Timers When Switching UMH
Consider a child node that has joined a particular IR P-tunnel via a Consider a child node that has joined a particular IR P-tunnel via a
particular UMH. To do so, it will have originated a Leaf A-D route particular UMH. To do so, it will have originated a Leaf A-D route
with an RT that identifies the UMH. Suppose the child node now with an RT that identifies the UMH. Suppose the child node now
determines (for whatever reason) that it needs to change its UMH for determines (for whatever reason) that it needs to change its UMH for
that P-tunnel. It does this by: that P-tunnel. It does this by:
o modifying the RT of the Leaf A-D route, so that the RT now o modifying the RT of the Leaf A-D route, so that the RT now
identifies the new parent rather than the old one, and by identifies the new parent rather than the old one, and by
skipping to change at page 19, line 34 skipping to change at page 19, line 46
field as discussed in Section 7. field as discussed in Section 7.
Note that, in accordance with the procedures of [RFC6514] and of Note that, in accordance with the procedures of [RFC6514] and of
Section 4 of this document, the NLRI of the Leaf A-D route is not Section 4 of this document, the NLRI of the Leaf A-D route is not
modified; only the RT and the PTA are changed. modified; only the RT and the PTA are changed.
It is desirable for such a "switch of UMH" to be done using a "make It is desirable for such a "switch of UMH" to be done using a "make
before break" technique, so that the old UMH does not stop before break" technique, so that the old UMH does not stop
transmitting packets of the given P-tunnel to the child until the new transmitting packets of the given P-tunnel to the child until the new
UMH has a chance to start transmitting packets of the given P-tunnel UMH has a chance to start transmitting packets of the given P-tunnel
to the child. However, the control plane operation (i.e., modifying to the child. However, the control-plane operation (i.e., modifying
the RT and PTA of the Leaf A-D route) does not permit the child node the RT and PTA of the Leaf A-D route) does not permit the child node
to first join the IR P-tunnel via the new UMH, and then later prune to first join the IR P-tunnel via the new UMH, and then later prune
itself from the old UMH. Rather, a single control plane operation itself from the old UMH. Rather, a single control-plane operation
has both effects. has both effects.
Therefore, the old UMH MUST continue transmitting to the child node Therefore, the old UMH MUST continue transmitting to the child node
for a period of time after it sees the child's Leaf A-D route being for a period of time after it sees the child's Leaf A-D route being
withdrawn (or its RT changing to identify a different UMH). This withdrawn (or its RT changing to identify a different UMH). This
timer (the "parent-continues" timer) SHOULD have a default value of timer (the "parent-continues" timer) SHOULD have a default value of
60 seconds, and SHOULD be configurable. 60 seconds and SHOULD be configurable.
By the procedures of Section 7, the child node will have advertised a By the procedures of Section 7, the child node will have advertised a
different label for the IR P-tunnel to the new UMH than it had different label for the IR P-tunnel to the new UMH than it had
advertised to the old UMH. This allows it to distinguish the packets advertised to the old UMH. This allows it to distinguish the packets
of that IR P-tunnel transmitted by the new UMH from packets of that of that IR P-tunnel transmitted by the new UMH from packets of that
IR P-tunnel transmitted by the old UMH. At any given time, the child IR P-tunnel transmitted by the old UMH. At any given time, the child
node will accept packets of that IR P-tunnel from only one parent node will accept packets of that IR P-tunnel from only one parent
node, and will discard packets of that IR P-tunnel that are received node and will discard packets of that IR P-tunnel that are received
from the other. To achieve "make before break" functionality, the from the other. To achieve "make before break" functionality, the
child node needs to continue to accept packets from the old UMH for a child node needs to continue to accept packets from the old UMH for a
period of time. After this period, it will discard any packets from period of time. After this period, it will discard any packets from
the given IR P-tunnel that it receives from the old UMH, and will the given IR P-tunnel that it receives from the old UMH and will only
only accept such packets from the new UMH. accept such packets from the new UMH.
Once the child node modifies the RT of its Leaf A-D route, it MUST Once the child node modifies the RT of its Leaf A-D route, it MUST
run a timer (the "switch-parents-delay" timer). This timer SHOULD run a timer (the "switch-parents-delay" timer). This timer SHOULD
default to 30 seconds, and SHOULD be configurable. The child node default to 30 seconds and SHOULD be configurable. The child node
MUST continue to accept packets of the given IR P-tunnel from the old MUST continue to accept packets of the given IR P-tunnel from the old
UMH until the timer expires. However, once the child node receives a UMH until the timer expires. However, once the child node receives a
packet of the given IR P-tunnel from the new UMH, it MAY consider the packet of the given IR P-tunnel from the new UMH, it MAY consider the
switch-parents-delay timer to have expired. "switch-parents-delay" timer to have expired.
The "parent-continues" timer MUST be longer than the "switch-parents- The "parent-continues" timer MUST be longer than the "switch-parents-
delay" timer. Note that both timers are specific to a given IR delay" timer. Note that both timers are specific to a given IR
P-tunnel. P-tunnel.
11. IANA Considerations 11. Security Considerations
This document contains no actions for IANA.
12. Acknowledgments
The authors wish to thank Yakov Rekhter for his contributions to this
work. We also wish to thank Huajin Jeng and Samir Saad for their
contributions, and to thank Thomas Morin for pointing out (both
before and after the document was written) some of the issues that
needed further elaboration. We also thank Lucy Yong for her review
and comments.
Section 7.1 discusses the importance of having an MPLS label
allocation policy that, when ingress replication is used, allows an
egress PE to infer the identity of a received packet's ingress PE.
This issue was first raised in earlier work by Xu Xiaohu.
13. Security Considerations
No security considerations are raised by this document beyond those No security considerations are raised by this document beyond those
already discussed in [RFC6513] and [RFC6514]. already discussed in [RFC6513] and [RFC6514].
14. References 12. References
14.1. Normative References 12.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997, DOI 10.17487/RFC2119, March 1997,
<http://www.rfc-editor.org/info/rfc2119>. <http://www.rfc-editor.org/info/rfc2119>.
[RFC6513] Rosen, E., Ed. and R. Aggarwal, Ed., "Multicast in MPLS/ [RFC6513] Rosen, E., Ed., and R. Aggarwal, Ed., "Multicast in
BGP IP VPNs", RFC 6513, DOI 10.17487/RFC6513, February MPLS/BGP IP VPNs", RFC 6513, DOI 10.17487/RFC6513,
2012, <http://www.rfc-editor.org/info/rfc6513>. February 2012, <http://www.rfc-editor.org/info/rfc6513>.
[RFC6514] Aggarwal, R., Rosen, E., Morin, T., and Y. Rekhter, "BGP [RFC6514] Aggarwal, R., Rosen, E., Morin, T., and Y. Rekhter, "BGP
Encodings and Procedures for Multicast in MPLS/BGP IP Encodings and Procedures for Multicast in MPLS/BGP IP
VPNs", RFC 6514, DOI 10.17487/RFC6514, February 2012, VPNs", RFC 6514, DOI 10.17487/RFC6514, February 2012,
<http://www.rfc-editor.org/info/rfc6514>. <http://www.rfc-editor.org/info/rfc6514>.
[RFC6515] Aggarwal, R. and E. Rosen, "IPv4 and IPv6 Infrastructure [RFC6515] Aggarwal, R. and E. Rosen, "IPv4 and IPv6 Infrastructure
Addresses in BGP Updates for Multicast VPN", RFC 6515, Addresses in BGP Updates for Multicast VPN", RFC 6515,
DOI 10.17487/RFC6515, February 2012, DOI 10.17487/RFC6515, February 2012,
<http://www.rfc-editor.org/info/rfc6515>. <http://www.rfc-editor.org/info/rfc6515>.
14.2. Informative References 12.2. Informative References
[RFC3209] Awduche, D., Berger, L., Gan, D., Li, T., Srinivasan, V., [RFC3209] Awduche, D., Berger, L., Gan, D., Li, T., Srinivasan, V.,
and G. Swallow, "RSVP-TE: Extensions to RSVP for LSP and G. Swallow, "RSVP-TE: Extensions to RSVP for LSP
Tunnels", RFC 3209, DOI 10.17487/RFC3209, December 2001, Tunnels", RFC 3209, DOI 10.17487/RFC3209, December 2001,
<http://www.rfc-editor.org/info/rfc3209>. <http://www.rfc-editor.org/info/rfc3209>.
[RFC5036] Andersson, L., Ed., Minei, I., Ed., and B. Thomas, Ed., [RFC5036] Andersson, L., Ed., Minei, I., Ed., and B. Thomas, Ed.,
"LDP Specification", RFC 5036, DOI 10.17487/RFC5036, "LDP Specification", RFC 5036, DOI 10.17487/RFC5036,
October 2007, <http://www.rfc-editor.org/info/rfc5036>. October 2007, <http://www.rfc-editor.org/info/rfc5036>.
skipping to change at page 22, line 27 skipping to change at page 23, line 5
Partial Mesh of Multipoint-to-Multipoint (MP2MP) Provider Partial Mesh of Multipoint-to-Multipoint (MP2MP) Provider
Tunnels with Ingress Replication", RFC 7740, Tunnels with Ingress Replication", RFC 7740,
DOI 10.17487/RFC7740, January 2016, DOI 10.17487/RFC7740, January 2016,
<http://www.rfc-editor.org/info/rfc7740>. <http://www.rfc-editor.org/info/rfc7740>.
[RFC7900] Rekhter, Y., Ed., Rosen, E., Ed., Aggarwal, R., Cai, Y., [RFC7900] Rekhter, Y., Ed., Rosen, E., Ed., Aggarwal, R., Cai, Y.,
and T. Morin, "Extranet Multicast in BGP/IP MPLS VPNs", and T. Morin, "Extranet Multicast in BGP/IP MPLS VPNs",
RFC 7900, DOI 10.17487/RFC7900, June 2016, RFC 7900, DOI 10.17487/RFC7900, June 2016,
<http://www.rfc-editor.org/info/rfc7900>. <http://www.rfc-editor.org/info/rfc7900>.
Acknowledgments
The authors wish to thank Yakov Rekhter for his contributions to this
work. We also wish to thank Huajin Jeng and Samir Saad for their
contributions, and to thank Thomas Morin for pointing out (both
before and after the document was written) some of the issues that
needed further elaboration. We also thank Lucy Yong for her review
and comments.
Section 7.1 discusses the importance of having an MPLS label
allocation policy that, when ingress replication is used, allows an
egress PE to infer the identity of a received packet's ingress PE.
This issue was first raised in earlier work by Xu Xiaohu.
Authors' Addresses Authors' Addresses
Eric C. Rosen (editor) Eric C. Rosen (editor)
Juniper Networks, Inc. Juniper Networks, Inc.
10 Technology Park Drive 10 Technology Park Drive
Westford, Massachusetts 01886 Westford, Massachusetts 01886
United States United States of America
Email: erosen@juniper.net Email: erosen@juniper.net
Karthik Subramanian Karthik Subramanian
Sproute Networks Sproute Networks
Email: karthik@sproute.com Email: karthik@sproute.com
Zhaohui Zhang Zhaohui Zhang
Juniper Networks, Inc. Juniper Networks, Inc.
10 Technology Park Drive 10 Technology Park Drive
Westford, Massachusetts 01886 Westford, Massachusetts 01886
United States United States of America
Email: zzhang@juniper.net Email: zzhang@juniper.net
 End of changes. 127 change blocks. 
311 lines changed or deleted 304 lines changed or added

This html diff was produced by rfcdiff 1.45. The latest version is available from http://tools.ietf.org/tools/rfcdiff/