draft-ietf-softwire-dslite-multicast-02.txt   draft-ietf-softwire-dslite-multicast-03.txt 
Softwire WG J. Qin Softwire WG J. Qin
Internet-Draft Cisco Internet-Draft Cisco
Intended status: Standards Track M. Boucadair Intended status: Standards Track M. Boucadair
Expires: November 5, 2012 C. Jacquenet Expires: February 24, 2013 C. Jacquenet
France Telecom France Telecom
Y. Lee Y. Lee
Comcast Comcast
Q. Wang Q. Wang
China Telecom China Telecom
May 4, 2012 August 23, 2012
Multicast Extensions to DS-Lite Technique in Broadband Deployments Delivery of IPv4 Multicast Services to IPv4 Clients over an IPv6
draft-ietf-softwire-dslite-multicast-02 Multicast Network
draft-ietf-softwire-dslite-multicast-03
Abstract Abstract
This document specifies a solution for the delivery of multicast This document specifies a solution for the delivery of IPv4 multicast
service offerings to DS-Lite serviced customers. The proposed services to IPv4 clients over an IPv6 multicast network. The
solution relies upon a stateless IPv4-in-IPv6 encapsulation scheme solution relies upon a stateless IPv4-in-IPv6 encapsulation scheme
and uses the IPv6 multicast distribution tree to deliver IPv4 and uses the IPv6 multicast distribution tree to deliver IPv4
multicast traffic over an IPv6 multicast-enabled network. multicast traffic. The solution is particularly useful for the
delivery of multicast service offerings to DS-Lite serviced
customers.
Status of this Memo Status of this Memo
This Internet-Draft is submitted in full conformance with the This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79. provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/. Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on November 5, 2012. This Internet-Draft will expire on February 24, 2013.
Copyright Notice Copyright Notice
Copyright (c) 2012 IETF Trust and the persons identified as the Copyright (c) 2012 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
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Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.1. Requirements Language . . . . . . . . . . . . . . . . . . 4 1.1. Requirements Language . . . . . . . . . . . . . . . . . . 4
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 5
3. Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 3. Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
4. Solution Overview . . . . . . . . . . . . . . . . . . . . . . 6 4. Solution Overview . . . . . . . . . . . . . . . . . . . . . . 6
4.1. IPv4-embedded IPv6 Prefixes . . . . . . . . . . . . . . . 7 4.1. IPv4-Embedded IPv6 Prefixes . . . . . . . . . . . . . . . 7
4.2. Multicast Distribution Tree Computation . . . . . . . . . 8 4.2. Multicast Distribution Tree Computation . . . . . . . . . 8
4.3. Multicast Data Forwarding . . . . . . . . . . . . . . . . 9 4.3. Multicast Data Forwarding . . . . . . . . . . . . . . . . 9
5. Address Mapping . . . . . . . . . . . . . . . . . . . . . . . 9 5. Address Mapping . . . . . . . . . . . . . . . . . . . . . . . 9
5.1. Prefix Assignment . . . . . . . . . . . . . . . . . . . . 9 5.1. Prefix Assignment . . . . . . . . . . . . . . . . . . . . 9
5.2. Examples . . . . . . . . . . . . . . . . . . . . . . . . . 10 5.2. Examples . . . . . . . . . . . . . . . . . . . . . . . . . 10
6. Multicast B4 (mB4) . . . . . . . . . . . . . . . . . . . . . . 10 6. Multicast B4 (mB4) . . . . . . . . . . . . . . . . . . . . . . 10
6.1. IGMP-MLD Interworking Function . . . . . . . . . . . . . . 10 6.1. IGMP-MLD Interworking Function . . . . . . . . . . . . . . 10
6.2. Multicast Data Forwarding . . . . . . . . . . . . . . . . 11 6.2. Multicast Data Forwarding . . . . . . . . . . . . . . . . 11
6.3. Fragmentation . . . . . . . . . . . . . . . . . . . . . . 11 6.3. Fragmentation . . . . . . . . . . . . . . . . . . . . . . 11
6.4. Host built-in mB4 Function . . . . . . . . . . . . . . . . 11 6.4. Host built-in mB4 Function . . . . . . . . . . . . . . . . 11
6.5. Preserve the Scope . . . . . . . . . . . . . . . . . . . . 12
7. Multicast AFTR (mAFTR) . . . . . . . . . . . . . . . . . . . . 12 7. Multicast AFTR (mAFTR) . . . . . . . . . . . . . . . . . . . . 12
7.1. Routing Considerations . . . . . . . . . . . . . . . . . . 12 7.1. Routing Considerations . . . . . . . . . . . . . . . . . . 12
7.2. Processing PIM Message . . . . . . . . . . . . . . . . . . 12 7.2. Processing PIM Message . . . . . . . . . . . . . . . . . . 12
7.3. Switching from Shared Tree to Shortest Path Tree . . . . . 13 7.3. Switching from Shared Tree to Shortest Path Tree . . . . . 13
7.4. Multicast Data Forwarding . . . . . . . . . . . . . . . . 13 7.4. Multicast Data Forwarding . . . . . . . . . . . . . . . . 13
7.5. TTL/Scope . . . . . . . . . . . . . . . . . . . . . . . . 14 7.5. TTL/Scope . . . . . . . . . . . . . . . . . . . . . . . . 14
8. Security Considerations . . . . . . . . . . . . . . . . . . . 14 8. Security Considerations . . . . . . . . . . . . . . . . . . . 14
8.1. Firewall Configuration . . . . . . . . . . . . . . . . . . 14 8.1. Firewall Configuration . . . . . . . . . . . . . . . . . . 14
9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 14 9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 15
10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 14 10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 15
11. References . . . . . . . . . . . . . . . . . . . . . . . . . . 15 11. References . . . . . . . . . . . . . . . . . . . . . . . . . . 15
11.1. Normative References . . . . . . . . . . . . . . . . . . . 15 11.1. Normative References . . . . . . . . . . . . . . . . . . . 15
11.2. Informative References . . . . . . . . . . . . . . . . . . 16 11.2. Informative References . . . . . . . . . . . . . . . . . . 16
Appendix A. Use Case: IPTV . . . . . . . . . . . . . . . . . . . 16 Appendix A. Use Case: IPTV . . . . . . . . . . . . . . . . . . . 16
Appendix B. Deployment Considerations . . . . . . . . . . . . . . 17 Appendix B. Deployment Considerations . . . . . . . . . . . . . . 17
B.1. Other operational Modes . . . . . . . . . . . . . . . . . 17 B.1. Other operational Modes . . . . . . . . . . . . . . . . . 17
B.1.1. MLD Querier with mAFTR Embedded . . . . . . . . . . . 17 B.1.1. MLD Querier with mAFTR Embedded . . . . . . . . . . . 17
B.1.2. mAFTR embedded in DR . . . . . . . . . . . . . . . . . 18 B.1.2. mAFTR embedded in DR . . . . . . . . . . . . . . . . . 18
B.2. Older Version of Group Membership management Protocols . . 18 B.2. Older Version of Group Membership management Protocols . . 18
B.3. Load-Balancing . . . . . . . . . . . . . . . . . . . . . . 18 B.3. Load-Balancing . . . . . . . . . . . . . . . . . . . . . . 18
skipping to change at page 4, line 12 skipping to change at page 4, line 12
B.6. Static vs. Dynamic PIM Triggering . . . . . . . . . . . . 18 B.6. Static vs. Dynamic PIM Triggering . . . . . . . . . . . . 18
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 19 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 19
1. Introduction 1. Introduction
DS-Lite [RFC6333] is a technique that rationalizes the usage of the DS-Lite [RFC6333] is a technique that rationalizes the usage of the
remaining global IPv4 addresses during the transition period by remaining global IPv4 addresses during the transition period by
sharing a single IPv4 address with multiple users. A typical DS-Lite sharing a single IPv4 address with multiple users. A typical DS-Lite
scenario is the delivery of an IPv4 service to an IPv4 user over an scenario is the delivery of an IPv4 service to an IPv4 user over an
IPv6 network (denoted as a 4-6-4 scenario). [RFC6333] covers unicast IPv6 network (denoted as a 4-6-4 scenario). [RFC6333] covers unicast
services exclusively. services exclusively. A more generic problem statement is sketched
in [I-D.ietf-mboned-v4v6-mcast-ps].
This document specifies a generic solution for delivery of IPv4
multicast services to IPv4 clients over an IPv6 multicast network.
The solution was developed with DS-Lite in mind (see more discussion
below). The solution is however not limited to DS-Lite.
If customers have to access IPv4 multicast-based services through DS- If customers have to access IPv4 multicast-based services through DS-
Lite environment, Address Family Transition Router (AFTR) devices Lite environment, Address Family Transition Router (AFTR) devices
will have to process all the IGMP Report messages [RFC2236] [RFC3376] will have to process all the IGMP Report messages [RFC2236] [RFC3376]
that have been forwarded by the CPE into the IPv4-in-IPv6 tunnels. that have been forwarded by the CPE into the IPv4-in-IPv6 tunnels.
From that standpoint, AFTR devices are likely to behave as a From that standpoint, AFTR devices are likely to behave as a
replication point for downstream multicast traffic. And the replication point for downstream multicast traffic. And the
multicast packets will be replicated for each tunnel endpoint where multicast packets will be replicated for each tunnel endpoint where
IPv4 receivers are connected to. IPv4 receivers are connected to.
skipping to change at page 5, line 33 skipping to change at page 5, line 37
source for the encapsulated IPv4-in-IPv6 packets. source for the encapsulated IPv4-in-IPv6 packets.
o Multicast B4 (mB4): is a functional entity which supports an IGMP- o Multicast B4 (mB4): is a functional entity which supports an IGMP-
MLD interworking function (refer to Section 6.1) that relays MLD interworking function (refer to Section 6.1) that relays
information conveyed in IGMP messages by forwarding the information conveyed in IGMP messages by forwarding the
corresponding MLD messages towards the MLD Querier in the IPv6 corresponding MLD messages towards the MLD Querier in the IPv6
network. In addition, the mB4 decapsulates IPv4-in-IPv6 multicast network. In addition, the mB4 decapsulates IPv4-in-IPv6 multicast
packets. packets.
o PIMv4: refers to PIM when deployed in an IPv4 infrastructure o PIMv4: refers to PIM when deployed in an IPv4 infrastructure
(i.e., IPv4 transfer capabilities are used to exchange PIM (i.e., IPv4 transport capabilities are used to exchange PIM
messages). messages).
o PIMv6: refers to PIM when deployed in an IPv6 infrastructure o PIMv6: refers to PIM when deployed in an IPv6 infrastructure
(i.e., IPv6 transfer capabilities are used to exchange PIM (i.e., IPv6 transport capabilities are used to exchange PIM
messages). messages).
3. Scope 3. Scope
This document focuses only on issues raised by a DS-Lite environment: This document focuses only on subscription to an IPv4 multicast group
subscription to an IPv4 multicast group and the delivery of IPv4- and the delivery of IPv4-formatted content to IPv4 receivers over an
formatted content to IPv4 receivers over an IPv6-only network. In IPv6-only network. In particular, only the following case is
particular, only the following case is covered: covered:
An IPv4 receiver accesses IPv4 multicast contents over an IPv6- An IPv4 receiver accesses IPv4 multicast contents over an IPv6-
only multicast-enabled network. only multicast-enabled network.
This document does not cover the source/receiver heuristics, where as This document does not cover the source/receiver heuristics, where as
IPv4 receiver can also behave as an IPv4 multicast source. This IPv4 receiver can also behave as an IPv4 multicast source. This
document assumes that hosts behind the mB4 are IPv4 multicast document assumes that hosts behind the mB4 are IPv4 multicast
receivers only. receivers only.
4. Solution Overview 4. Solution Overview
In the original DS-Lite specification [RFC6333], an IPv4-in-IPv6 In the original DS-Lite specification [RFC6333], an IPv4-in-IPv6
tunnel is used to carry bidirectional IPv4 unicast traffic between a tunnel is used to carry bidirectional IPv4 unicast traffic between a
B4 and an AFTR. An extension to DS-Lite is proposed in this document B4 and an AFTR. The solution specified in this document provides an
which specifies an IPv4-in-IPv6 encapsulation scheme to deliver IPv4-in-IPv6 encapsulation scheme to deliver unidirectional IPv4
unidirectional IPv4 multicast traffic from a mAFTR to a mB4. multicast traffic from an mAFTR to an mB4.
An overview of the solution is provided in this section which is An overview of the solution is provided in this section which is
intended as an introduction to how it works, but is NOT normative. intended as an introduction to how it works, but is NOT normative.
For the normative specifications of the two new functional elements: For the normative specifications of the two new functional elements:
mB4 and mAFTR (Figure 1), refer to Section 6 and Section 7. mB4 and mAFTR (Figure 1), refer to Section 6 and Section 7.
------------ ------------
/ \ / \
| IPv4 network | | IPv4 network |
\ / \ /
skipping to change at page 7, line 36 skipping to change at page 7, line 36
+-----------+ +-----------+
IPv4 multicast : | ^ IGMP Report IPv4 multicast : | ^ IGMP Report
v | : v | :
+-----------+ +-----------+
| IPv4 | | IPv4 |
| receiver | | receiver |
+-----------+ +-----------+
Figure 1: Functional Architecture Figure 1: Functional Architecture
4.1. IPv4-embedded IPv6 Prefixes 4.1. IPv4-Embedded IPv6 Prefixes
In order to map the addresses of IPv4 multicast traffic with IPv6 In order to map the addresses of IPv4 multicast traffic with IPv6
multicast addresses, an IPv6 multicast prefix (mPrefix64) and an IPv6 multicast addresses, an IPv6 multicast prefix (mPrefix64) and an IPv6
unicast prefix (uPrefix64) are provided to mAFTR and mB4 elements, unicast prefix (uPrefix64) are provided to mAFTR and mB4 elements,
both of which contribute to the computation and the maintenance of both of which contribute to the computation and the maintenance of
the IPv6 multicast distribution tree that extends the IPv4 multicast the IPv6 multicast distribution tree that extends the IPv4 multicast
distribution tree into the IPv6 multicast network. distribution tree into the IPv6 multicast network.
The mAFTR and mB4 use mPrefix64 to convert an IPv4 multicast address The mAFTR and mB4 use mPrefix64 to convert an IPv4 multicast address
(G4) to an IPv4-embedded IPv6 multicast address (G6). The mAFTR and (G4) to an IPv4-embedded IPv6 multicast address (G6). The mAFTR and
mB4 use uPrefix64 to convert an IPv4 multicast source address (S4) to mB4 use uPrefix64 to convert an IPv4 multicast source address (S4) to
an IPv4-embedded IPv6 address (S6). The mAFTR and mB4 MUST use the an IPv4-embedded IPv6 address (S6). The mAFTR and mB4 MUST use the
same mPrefix64 and uPrefix64, as well as run the same algorithm for same mPrefix64 and uPrefix64, as well as run the same algorithm for
building IPv4-embedded IPv6 addresses. Refer to Section 5 for more building IPv4-embedded IPv6 addresses. Refer to Section 5 for more
details about the address mapping. details about the address mapping.
4.2. Multicast Distribution Tree Computation 4.2. Multicast Distribution Tree Computation
When an IPv4 receiver connected to the mB4 wants to subscribe to an When an IPv4 receiver connected to the device that embeds the mB4
IPv4 multicast group, it sends an IGMP Report message to the mB4. capability wants to subscribe to an IPv4 multicast group, it sends an
The mB4 creates the IPv6 multicast group (G6) address using mPrefix64 IGMP Report message to the mB4. The mB4 creates the IPv6 multicast
and the original IPv4 multicast gorup address. If the receiver sends group (G6) address using mPrefix64 and the original IPv4 multicast
a source-specific IGMPv3 Report message, the mB4 will create the IPv6 group address. If the receiver sends a source-specific IGMPv3 Report
source address (S6) using uPrefix64 and the original IPv4 source message, the mB4 will create the IPv6 source address (S6) using
address. uPrefix64 and the original IPv4 source address.
The mB4 uses the G6 (and both S6 and G6 in SSM) to create the The mB4 uses the G6 (and both S6 and G6 in SSM) to create the
corresponding MLD Report message. The mB4 sends the Report message corresponding MLD Report message. The mB4 sends the Report message
to the MLD Querier in the IPv6 network. The MLD Querier (typically to the MLD Querier in the IPv6 network. The MLD Querier (typically
acts as the PIMv6 Designated Router) receives the MLD Report message acts as the PIMv6 Designated Router) receives the MLD Report message
and sends the PIMv6 Join to join the IPv6 multicast distribution and sends the PIMv6 Join to join the IPv6 multicast distribution
tree. The MLD Querier can send either PIMv6 Join (*,G6) in ASM or tree. The MLD Querier can send either PIMv6 Join (*,G6) in ASM or
PIMv6 Join (S6,G6) in SSM to the mAFTR. PIMv6 Join (S6,G6) in SSM to the mAFTR.
The mAFTR acts as the DR to which the uPrefix64-derived S6 is The mAFTR acts as the DR to which the uPrefix64-derived S6 is
skipping to change at page 8, line 44 skipping to change at page 8, line 44
(if there is not yet an existing one) in its own IPv4 multicast (if there is not yet an existing one) in its own IPv4 multicast
routing table. If the mAFTR is not the RP of G4, it will send the routing table. If the mAFTR is not the RP of G4, it will send the
corresponding PIMv4 Join message (*,G4) towards the RP of G4 in the corresponding PIMv4 Join message (*,G4) towards the RP of G4 in the
IPv4 multicast network. IPv4 multicast network.
When the mAFTR receives the PIMv6 Join message (S6,G6), it will When the mAFTR receives the PIMv6 Join message (S6,G6), it will
extract the IPv4 multicast group address (G4) and IPv4 source address extract the IPv4 multicast group address (G4) and IPv4 source address
(S4) and send the corresponding (S4,G4) PIMv4 Join message directly (S4) and send the corresponding (S4,G4) PIMv4 Join message directly
to the IPv4 source. to the IPv4 source.
A branch of the multicast distribution tree is then grafted, A branch of the multicast distribution tree is constructed,
comprising both an IPv4 part (from the mAFTR upstream) and an IPv6 comprising both an IPv4 part (from the mAFTR upstream) and an IPv6
part (from mAFTR downstream to the mB4). part (from mAFTR downstream to the mB4).
The mAFTR MUST advertise the route of uPrefix64 with an IPv6 IGP, so The mAFTR MUST advertise the route of uPrefix64 with an IPv6 IGP, so
as to represent the IPv4-embedded IPv6 source in the IPv6 multicast as to represent the IPv4-embedded IPv6 source in the IPv6 multicast
network. network, and to pass the Reverse Path Forwarding (RPF) check on
multicast devices.
4.3. Multicast Data Forwarding 4.3. Multicast Data Forwarding
When the mAFTR receives an IPv4 multicast packet, it will encapsulate When the mAFTR receives an IPv4 multicast packet, it will encapsulate
the packet into an IPv6 multicast packet using the IPv4-embedded IPv6 the packet into an IPv6 multicast packet using the IPv4-embedded IPv6
multicast address as the destination address and an IPv4-embedded multicast address as the destination address and an IPv4-embedded
IPv6 unicast address as the source address. The encapsulated IPv6 IPv6 unicast address as the source address. The encapsulated IPv6
multicast packet will be forwarded down the IPv6 multicast multicast packet will be forwarded down the IPv6 multicast
distribution tree and the mB4 will eventually receive the packet. distribution tree and the mB4 will eventually receive the packet.
The IPv6 multicast network treats the IPv4-in-IPv6 encapsulated The IPv6 multicast network treats the IPv4-in-IPv6 encapsulated
multicast packets as native. The IPv6 multicast routers use the multicast packets as native. The IPv6 multicast routers use the
outer IPv6 header to make forwarding decisions. outer IPv6 header to make forwarding decisions.
When the mB4 receive the IPv6 multicast packet (to G6) derived by When the mB4 receive the IPv6 multicast packet (to G6) derived by
mPrefix64, it MUST decapsulate it and forward the original IPv4 mPrefix64, it MUST decapsulate it and forward the original IPv4
multicast packet to the receivers subscribing to G4. multicast packet to the receivers subscribing to G4.
Note: At this point, only IPv4-in-IPv6 encapsulation is defined;
however, other types of encapsulation could be defined in the future.
5. Address Mapping 5. Address Mapping
5.1. Prefix Assignment 5.1. Prefix Assignment
A dedicated IPv6 multicast prefix (mPrefix64) is provisioned to the A dedicated IPv6 multicast prefix (mPrefix64) is provisioned to the
mAFTR and the mB4. The mAFTR and the mB4 use the mPrefix64 to form mAFTR and the mB4. The mAFTR and the mB4 use the mPrefix64 to form
an IPv6 multicast group address from an IPv4 multicast group address. an IPv6 multicast group address from an IPv4 multicast group address.
The mPrefix64 can be of two types: ASM_mPrefix64 (a mPrefix64 used in The mPrefix64 can be of two types: ASM_mPrefix64 (a mPrefix64 used in
ASM mode) or SSM_mPrefix64 (a mPrefix64 used in SSM mode). The ASM mode) or SSM_mPrefix64 (a mPrefix64 used in SSM mode). The
mPrefix64 Must be derived from the corresponding IPv6 multicast mPrefix64 Must be derived from the corresponding IPv6 multicast
skipping to change at page 10, line 9 skipping to change at page 10, line 12
network provider. The address synthesizing MUST follow network provider. The address synthesizing MUST follow
[I-D.ietf-mboned-64-multicast-address-format] and [RFC6052]. [I-D.ietf-mboned-64-multicast-address-format] and [RFC6052].
The mPrefix64 and uPrefix64 can be configured in the mB4 using a The mPrefix64 and uPrefix64 can be configured in the mB4 using a
variety of methods, including an out-of-band mechanism, manual variety of methods, including an out-of-band mechanism, manual
configuration, or a dedicated provisioning protocol (e.g., using configuration, or a dedicated provisioning protocol (e.g., using
DHCPv6 [I-D.ietf-softwire-multicast-prefix-option]). DHCPv6 [I-D.ietf-softwire-multicast-prefix-option]).
5.2. Examples 5.2. Examples
Group address mapping example when a /96 is used: Group address mapping example:
+---------------------+--------------+----------------------------+ +---------------------+--------------+----------------------------+
| mPrefix64 | IPv4 address | IPv4-Embedded IPv6 address | | mPrefix64 | IPv4 address | IPv4-Embedded IPv6 address |
+---------------------+--------------+----------------------------+ +---------------------+--------------+----------------------------+
| ffxx:abc::/96 | 230.1.2.3 | ffxx:abc::230.1.2.3 | | ff3x:1000::/96 | 233.252.0.1 | ff3x:1000::233.252.0.1 |
+---------------------+--------------+----------------------------+ +---------------------+--------------+----------------------------+
Source address mapping example when a /96 is used: Source address mapping example when a /96 is used:
+---------------------+--------------+----------------------------+ +---------------------+--------------+----------------------------+
| uPrefix64 | IPv4 address | IPv4-Embedded IPv6 address | | uPrefix64 | IPv4 address | IPv4-Embedded IPv6 address |
+---------------------+--------------+----------------------------+ +---------------------+--------------+----------------------------+
| 2001:db8::/96 | 192.1.2.3 | 2001:db8::192.1.2.3 | | 2001:db8::/96 | 192.0.2.33 | 2001:db8::192.0.2.33 |
+---------------------+--------------+----------------------------+ +---------------------+--------------+----------------------------+
IPv4 multicast address used in the example is derived from the IPv4
multicast block reserved for documentation in [RFC6676] while the
unicast IPv4 address is derived from [RFC5735].
6. Multicast B4 (mB4) 6. Multicast B4 (mB4)
6.1. IGMP-MLD Interworking Function 6.1. IGMP-MLD Interworking Function
The IGMP-MLD Interworking Function combines the IGMP/MLD Proxying The IGMP-MLD Interworking Function combines the IGMP/MLD Proxying
function and the IGMP/MLD translation function. The IGMP/MLD function and the address synthesizing operations. The IGMP/MLD
Proxying function is specified in [RFC4605]. The IGMP/MLD Proxying function is specified in [RFC4605]. The address
translation function translates the contents of IGMP messages into synthesizing is stateless and MUST follow
MLD messages by using a stateless algorithm. The address [I-D.ietf-mboned-64-multicast-address-format] and [RFC6052].
synthesizing MUST comply with the rules documented in Section 5. MLD
messages will be forwarded natively towards the MLD Querier located
upstream in the IPv6 network. The mB4 performs the IGMP-MLD
Interworking Function to relay between the IGMP messages and the MLD
messages.
The mB4 with the IGMP-MLD Interworking Function embedded relays
between the IGMP domain and the MLD domain. The mB4 performs the
host portion of the MLD protocol on the upstream interface. The
composition of IPv6 membership in this context is constructed through
address synthesizing operations and MUST synchronize with the
membership database maintained in the IGMP domain. MLD messages will
be forwarded natively towards the MLD Querier located upstream in the
IPv6 network. The mB4 also performs the router portion of the IGMP
protocol on the downstream interface(s). Refer to [RFC4605] for more
details
+----------+ IGMP +-------+ MLD +---------+ +----------+ IGMP +-------+ MLD +---------+
| IPv4 |---------| mB4 |---------| MLD | | IPv4 |---------| mB4 |---------| MLD |
| Receiver | | | | Querier | | Receiver | | | | Querier |
+----------+ +-------+ +---------+ +----------+ +-------+ +---------+
Figure 2: IGMP-MLD Interworking Figure 2: IGMP-MLD Interworking
When the mB4 receives an IGMP Report message from a receiver to
subscribe to multicast group (and optionally associated to a source
in SSM mode), it MUST translate the IGMP Report message into a MLD
Report message and send to the MLD Querier. The mB4 MUST construct
the IPv6 multicast group address using the mPrefix64.
When the mB4 receives an MLD Listener Query message from the MLD
Querier, it MUST convert the MLD listener Query message to the IGMP
Query message and send it to the IPv4 receiver(s). The mB4 MUST
retrieve the IPv4 multicast group address using the mPrefix64.
If SSM is deployed, the mB4 MUST construct the IPv6 source address If SSM is deployed, the mB4 MUST construct the IPv6 source address
(or retrieve the IPv4 source address) using the uPrefix64. The mB4 (or retrieve the IPv4 source address) using the uPrefix64. The mB4
may create a membership database which associates the IPv4-IPv6 may create a membership database which associates the IPv4-IPv6
multicast groups with the interfaces (e.g., Wi-Fi and Wired Ethernet) multicast groups with the interfaces (e.g., Wi-Fi and Wired Ethernet)
facing IPv4 multicast receivers. facing IPv4 multicast receivers.
6.2. Multicast Data Forwarding 6.2. Multicast Data Forwarding
When the mB4 receives an IPv6 multicast packet, it MUST check the When the mB4 receives an IPv6 multicast packet, it MUST check the
group address and the source address. If the IPv6 multicast group group address and the source address. If the IPv6 multicast group
prefix is mPrefix64 and the IPv6 source prefix is uPrefix64, the mB4 prefix is mPrefix64 and the IPv6 source prefix is uPrefix64, the mB4
MUST de-capsulate the IPv6 header and forward the IPv4 multicast MUST de-capsulate the IPv6 header and forward the IPv4 multicast
packet through each relevant interface. Otherwise, the mB4 MUST drop packet through each relevant interface. Otherwise, the mB4 MUST drop
the packet silently. the packet silently.
As an illustration, if a packet is received from source 2001:db8:: As an illustration, if a packet is received from source 2001:db8::
192.1.2.3 and to be forwarded to group ffxx:abc::230.1.2.3, the mB4 192.0.2.33 and to be forwarded to group ff3x:1000::233.252.0.1, the
will de-capsulate it into an IPv4 multicast packet using 192.1.2.3 as mB4 will de-capsulate it into an IPv4 multicast packet using
the IPv4 multicast source address and using 230.1.2.3 as the IPv4 192.0.2.33 as the IPv4 multicast source address and using 233.252.0.1
destination address. as the IPv4 destination address.
6.3. Fragmentation 6.3. Fragmentation
Encapsulating IPv4 multicast packets into IPv6 multicast packets that Encapsulating IPv4 multicast packets into IPv6 multicast packets that
will be forwarded by the mAFTR to the mB4 along the IPv6 multicast will be forwarded by the mAFTR to the mB4 along the IPv6 multicast
distribution tree reduces the effective MTU size by the size of an distribution tree reduces the effective MTU size by the size of an
IPv6 header. In this specification, the data flow is unidirection IPv6 header. In this specification, the data flow is unidirectional
from mAFTR to mB4, the mAFTR must fragment the oversized IPv6 packet from mAFTR to mB4, the mAFTR must fragment the oversized IPv6 packet
after the encapsulation into two IPv6 packets. The mB4 MUST after the encapsulation into two IPv6 packets. The mB4 MUST
reassemable the IPv6 packets, decapsulate the IPv6 packet, and reassemble the IPv6 packets, decapsulate the IPv6 packet, and forward
forward the IPv4 packet to the hosts subscribing the multicast group. the IPv4 packet to the hosts subscribing the multicast group.
Further considerations about fragmentation issues are documented in Further considerations about fragmentation issues are documented in
[RFC6333]. [RFC6333].
6.4. Host built-in mB4 Function 6.4. Host built-in mB4 Function
If the mB4 function is implemented in the host which is directly If the mB4 function is implemented in the host which is directly
connected to an IPv6-only network. If an IPv4 application running in connected to an IPv6-only network, the host MUST implement
the host requests to subscribe an IPv4 multicast stream, the host Section 6.1, Section 6.2, and Section 6.3. The host MAY optimize the
MUST implement Section 6.1, Section 6.2, and Section 6.3. The host implementation to provide an Application Programming Interface (API)
MAY optimize the implemntation to provide an Application Programming or kernel module to skip the IGMP-MLD Interworking Function. The
Interface (API) or kernel module to skip the IGMP-MLD Interworking optimization is out of scope of the specification.
Function. The optimization is out of scope of the specification.
6.5. Preserve the Scope
When several mPrefix64s are available, if each enclosed IPv4-embedded
IPv6 multicast prefix has a distinct scope, mB4 MUST select the
appropriate IPv4-embedded IPv6 multicast prefix having a scope
matching the IPv4 multicast address used to synthesize an IPv4-
embedded IPv6 multicast address. mB4 MAY be configured to not
preserve the scope when enforcing the address translation algorithm.
7. Multicast AFTR (mAFTR) 7. Multicast AFTR (mAFTR)
7.1. Routing Considerations 7.1. Routing Considerations
The mAFTR is responsible for interconnecting the IPv4 multicast The mAFTR is responsible for interconnecting the IPv4 multicast
distribution tree with the corresponding IPv6 multicast distribution distribution tree with the corresponding IPv6 multicast distribution
tree. The mAFTR MUST use the uPrefix64 to build the IPv6 source tree. The mAFTR MUST use the uPrefix64 to build the IPv6 source
addresses of the multicast group address derived from mPrefix64. In addresses of the multicast group address derived from mPrefix64. In
other words, the mAFTR MUST be the multicast source derived from other words, the mAFTR MUST be the multicast source derived from
uPrefix64. uPrefix64.
The mAFTR MUST advertise the route of uPrefix64 to the IPv6 IGP. The mAFTR MUST advertise the route of uPrefix64 to the IPv6 IGP.
This is needed for the IPv6 multicast routers to have routing This is needed for the IPv6 multicast routers to have routing
information to discover the source. In order to pass the Reverse information to discover the source.
Path Forwarding (RPF) check, the IPv6 routers MUST enable PIM on the
interfaces which has the shortest path to the uPrefix64.
7.2. Processing PIM Message 7.2. Processing PIM Message
The mAFTR MUST interwork PIM Join/Prune messages for (*, G6) and (S6, The mAFTR MUST interwork PIM Join/Prune messages for (*, G6) and (S6,
G6) on their corresponding (*, G4) and (S4, G4). The following text G6) on their corresponding (*, G4) and (S4, G4). The following text
specifies the expected behavior of mAFTR for PIM Join message. specifies the expected behavior of mAFTR for PIM Join message.
+---------+ +---------+
---------| mAFTR |--------- ---------| mAFTR |---------
PIMv6 |uPrefix64| PIMv4 PIMv6 |uPrefix64| PIMv4
|mPreifx64| |mPreifx64|
+---------+ +---------+
Figure 3: PIMv6-PIMv4 Interworking Function Figure 3: PIMv6-PIMv4 Interworking Function
The mAFTR contains two separate multicast routing table (mRIB): IPv4 The mAFTR contains two separate Tree Information Base (TIB): IPv4
multicast routing table (mRIB4) and IPv6 multicast routing table Tree Information Base (TIB4) and IPv6 Tree Information Base (TIB6),
(mRIB6), which are bridged by one IPv4-in-IPv6 virtual interface. It which are bridged by one IPv4-in-IPv6 virtual interface. It should
should be noted that the implementations may vary (e.g., using one be noted that the implementations may vary (e.g., using one
integrated mRIB without any virtual interface), while they should integrated TIB without any virtual interface), while they should
follow the specification herein for the consistency of overall follow the specification herein for the consistency of overall
functionality. functionality.
When a mAFTR receives a PIMv6 Join message (*,G6) with an IPv6 When a mAFTR receives a PIMv6 Join message (*,G6) with an IPv6
multicast group address (G6) that is derived from the mPrefix64, it multicast group address (G6) that is derived from the mPrefix64, it
MUST check its IPv6 multicast routing table (mRIB6). If there is an MUST check its IPv6 Tree Information Base (TIB6). If there is an
entry for this G6, it MUST check whether the interface through which entry for this G6, it MUST check whether the interface through which
the PIMv6 Join message has been received is on the outgoing interface the PIMv6 Join message has been received is on the outgoing interface
list. If not, the mAFTR MUST add the interface to the outgoing list. If not, the mAFTR MUST add the interface to the outgoing
interface list. If there is no entry in the mRIB6, the mAFTR MUST interface list. If there is no entry in the TIB6, the mAFTR MUST
create a new entry (*,G6) for the multicast group. While, whether or create a new entry (*,G6) for the multicast group. While, whether or
not to set the IPv4-in-IPv6 virtual interface as the incoming not to set the IPv4-in-IPv6 virtual interface as the incoming
interface of the newly created entry is up to the implementation but interface of the newly created entry is up to the implementation but
should comply with the mAFTR's behavior of multicast data forwarding, should comply with the mAFTR's behavior of multicast data forwarding,
see Section 7.4. see Section 7.4.
The mAFTR MUST extract the IPv4 multicast group address (G4) from the The mAFTR MUST extract the IPv4 multicast group address (G4) from the
IPv4-embedded IPv6 multicast address (G6) contained in the PIMv6 Join IPv4-embedded IPv6 multicast address (G6) contained in the PIMv6 Join
message. The mAFTR MUST check its IPv4 multicast routing table message. The mAFTR MUST check its IPv4 Tree Information Base (TIB4).
(mRIB4). If there is an entry for G4, it MUST check whether the If there is an entry for G4, it MUST check whether the IPv4-in-IPv6
IPv4-in-IPv6 virtual interface is on the outgoing interface list. If virtual interface is on the outgoing interface list. If not, the
not, the mAFTR MUST add the interface to the outgoing interface list. mAFTR MUST add the interface to the outgoing interface list. If
If there is no entry for G4, the mAFTR MUST create a new (*,G4) entry there is no entry for G4, the mAFTR MUST create a new (*,G4) entry in
in its mRIB4 and initiate the procedure for building the shared tree its TIB4 and initiate the procedure for building the shared tree in
in the IPv4 multicast network without any additional requirement. the IPv4 multicast network without any additional requirement.
If mAFTR receives a source-specific Join message, the (S6, G6) will If mAFTR receives a source-specific Join message, the (S6, G6) will
be processed rather than (*,G6). The procedures of processing be processed rather than (*,G6). The procedures of processing
(S6,G6) and (*,G6) are almost the same. Differences have been (S6,G6) and (*,G6) are almost the same. Differences have been
detailed in [RFC4601]. detailed in [RFC4601].
7.3. Switching from Shared Tree to Shortest Path Tree 7.3. Switching from Shared Tree to Shortest Path Tree
When the mAFTR receives the first IPv4 multicast packet, it may When the mAFTR receives the first IPv4 multicast packet, it may
extract the multicast source address (S4) from the packet and send an extract the multicast source address (S4) from the packet and send an
skipping to change at page 13, line 44 skipping to change at page 13, line 50
Path Tree (SPT) for G4. Path Tree (SPT) for G4.
For IPv6 multicast routers to switch to the SPT, there is no new For IPv6 multicast routers to switch to the SPT, there is no new
requirement. IPv6 multicast routers may send an Explicit PIMv6 Join requirement. IPv6 multicast routers may send an Explicit PIMv6 Join
to mAFTR once the first (S6,G6) multicast packet arrives from to mAFTR once the first (S6,G6) multicast packet arrives from
upstream multicast routers. upstream multicast routers.
7.4. Multicast Data Forwarding 7.4. Multicast Data Forwarding
When the mAFTR receives an IPv4 multicast packet, it will look up the When the mAFTR receives an IPv4 multicast packet, it will look up the
mRIB4 to find a matching entry and then forward the packet to the TIB4 to find a matching entry and then forward the packet to the
interface(s) on the outgoing interface list. If the IPv4-in-IPv6 interface(s) on the outgoing interface list. If the IPv4-in-IPv6
virtual interface also belongs to this list, the packet will be virtual interface also belongs to this list, the packet will be
encapsulated with the mPrefix64-derived and uPrefix64-derived IPv4- encapsulated with the mPrefix64-derived and uPrefix64-derived IPv4-
embedded IPv6 addresses to form an IPv6 multicast packet. Then embedded IPv6 addresses to form an IPv6 multicast packet. Then
another lookup is executed to find a matching entry in the mRIB6, another lookup is executed to find a matching entry in the TIB6,
while whether or not to perform RPF check for the second lookup is up while whether or not to perform RPF check for the second lookup is up
to the implementation and is out of the scope of this document. The to the implementation and is out of the scope of this document. The
IPv6 multicast packet is forwarded along the IPv6 multicast IPv6 multicast packet is forwarded along the IPv6 multicast
distribution tree, based upon the outgoing interface list of the distribution tree, based upon the outgoing interface list of the
matching entry in the mRIB6. matching entry in the TIB6.
As an illustration, if a packet is received from source 192.1.2.3 and As an illustration, if a packet is received from source 192.0.2.33
to be forwarded to group 230.1.2.3, the mAFTR encapsulates it into an and to be forwarded to group 233.252.0.1, the mAFTR encapsulates it
IPv6 multicast packet using ffxx:abc::230.1.2.3 as the IPv6 into an IPv6 multicast packet using ff3x:1000::233.252.0.1 as the
destination address and using 2001:db8::192.1.2.3 as the IPv6 IPv6 destination address and using 2001:db8::192.0.2.33 as the IPv6
multicast source address. multicast source address.
7.5. TTL/Scope 7.5. TTL/Scope
The Scope field of IPv4-in-IPv6 multicast addresses can be valued to The Scope field of IPv4-in-IPv6 multicast addresses should be valued
"E" (Global scope) or to "8" (Organization-local scope). This accordingly (e.g, to "E", Global scope;) in the deployment
specification does not discuss the scope value that should be used. environment. This specification does not discuss the scope value
that should be used.
Nevertheless, when several mPrefix64s are available, if each enclosed
IPv4-embedded IPv6 multicast prefix has a distinct scope, mAFTR MUST
select the appropriate IPv4-embedded IPv6 multicast prefix having a
scope matching the IPv4 multicast address used to synthesize an IPv4-
embedded IPv6 multicast address. mAFTR MAY be configured to not
preserve the scope when enforcing the address translation algorithm.
8. Security Considerations 8. Security Considerations
This document does not introduce any new security concern in addition A part for multicast scoping considerations (see Section 6.5 and
to what is discussed in Section 5 of [RFC6052], Section 10 of Section 7.5), this document does not introduce any new security
[RFC3810] and Section 6 of [RFC4601]. concern in addition to what is discussed in Section 5 of [RFC6052],
Section 10 of [RFC3810] and Section 6 of [RFC4601].
mB4 SHOULD be provided with appropriate configuration to enable
preserving the scope of a multicast message when mapping an IPv4
multicast address into an IPv4-embedded IPv6 multicast address and
vice versa.
8.1. Firewall Configuration 8.1. Firewall Configuration
The CPE with mB4 function embedded should be configured to accept The CPE that embeds the mB4 function SHOULD be configured to accept
incoming MLD messages and traffic forwarded to multicast groups incoming MLD messages and traffic forwarded to multicast groups
subscribed by receivers located in the customer premises. subscribed by receivers located in the customer premises.
9. Acknowledgements 9. Acknowledgements
The authors would like to thank Dan Wing for his guidance in the The authors would like to thank Dan Wing for his guidance in the
early discussions which initiated this work. We also thank Peng Sun, early discussions which initiated this work. We also thank Peng Sun,
Jie Hu, Qiong Sun, Lizhong Jin, Alain Durand, Dean Cheng, Behcet Jie Hu, Qiong Sun, Lizhong Jin, Alain Durand, Dean Cheng, Behcet
Sarikaya, Tina Tsou, Rajiv Asati, and Xiaohong Deng for their Sarikaya, Tina Tsou, Rajiv Asati, Xiaohong Deng and S. Venaas for
valuable comments. their valuable comments.
10. IANA Considerations 10. IANA Considerations
This document includes no request to IANA. This document includes no request to IANA.
11. References 11. References
11.1. Normative References 11.1. Normative References
[I-D.ietf-mboned-64-multicast-address-format] [I-D.ietf-mboned-64-multicast-address-format]
Boucadair, M., Qin, J., Lee, Y., Venaas, S., Li, X., and Boucadair, M., Qin, J., Lee, Y., Venaas, S., Li, X., and
M. Xu, "IPv4-Embedded IPv6 Multicast Address Format", M. Xu, "IPv6 Multicast Address With Embedded IPv4
draft-ietf-mboned-64-multicast-address-format-01 (work in Multicast Address",
progress), February 2012. draft-ietf-mboned-64-multicast-address-format-03 (work in
progress), August 2012.
[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, March 1997. Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC2710] Deering, S., Fenner, W., and B. Haberman, "Multicast
Listener Discovery (MLD) for IPv6", RFC 2710,
October 1999.
[RFC3376] Cain, B., Deering, S., Kouvelas, I., Fenner, B., and A. [RFC3376] Cain, B., Deering, S., Kouvelas, I., Fenner, B., and A.
Thyagarajan, "Internet Group Management Protocol, Version Thyagarajan, "Internet Group Management Protocol, Version
3", RFC 3376, October 2002. 3", RFC 3376, October 2002.
[RFC3810] Vida, R. and L. Costa, "Multicast Listener Discovery [RFC3810] Vida, R. and L. Costa, "Multicast Listener Discovery
Version 2 (MLDv2) for IPv6", RFC 3810, June 2004. Version 2 (MLDv2) for IPv6", RFC 3810, June 2004.
[RFC4601] Fenner, B., Handley, M., Holbrook, H., and I. Kouvelas, [RFC4601] Fenner, B., Handley, M., Holbrook, H., and I. Kouvelas,
"Protocol Independent Multicast - Sparse Mode (PIM-SM): "Protocol Independent Multicast - Sparse Mode (PIM-SM):
Protocol Specification (Revised)", RFC 4601, August 2006. Protocol Specification (Revised)", RFC 4601, August 2006.
skipping to change at page 15, line 39 skipping to change at page 16, line 4
[RFC4605] Fenner, B., He, H., Haberman, B., and H. Sandick, [RFC4605] Fenner, B., He, H., Haberman, B., and H. Sandick,
"Internet Group Management Protocol (IGMP) / Multicast "Internet Group Management Protocol (IGMP) / Multicast
Listener Discovery (MLD)-Based Multicast Forwarding Listener Discovery (MLD)-Based Multicast Forwarding
("IGMP/MLD Proxying")", RFC 4605, August 2006. ("IGMP/MLD Proxying")", RFC 4605, August 2006.
[RFC4607] Holbrook, H. and B. Cain, "Source-Specific Multicast for [RFC4607] Holbrook, H. and B. Cain, "Source-Specific Multicast for
IP", RFC 4607, August 2006. IP", RFC 4607, August 2006.
[RFC6052] Bao, C., Huitema, C., Bagnulo, M., Boucadair, M., and X. [RFC6052] Bao, C., Huitema, C., Bagnulo, M., Boucadair, M., and X.
Li, "IPv6 Addressing of IPv4/IPv6 Translators", RFC 6052, Li, "IPv6 Addressing of IPv4/IPv6 Translators", RFC 6052,
October 2010. October 2010.
[RFC6145] Li, X., Bao, C., and F. Baker, "IP/ICMP Translation
Algorithm", RFC 6145, April 2011.
[RFC6333] Durand, A., Droms, R., Woodyatt, J., and Y. Lee, "Dual- [RFC6333] Durand, A., Droms, R., Woodyatt, J., and Y. Lee, "Dual-
Stack Lite Broadband Deployments Following IPv4 Stack Lite Broadband Deployments Following IPv4
Exhaustion", RFC 6333, August 2011. Exhaustion", RFC 6333, August 2011.
11.2. Informative References 11.2. Informative References
[I-D.ietf-mboned-multiaaa-framework] [I-D.ietf-mboned-multiaaa-framework]
Satou, H., Ohta, H., Hayashi, T., Jacquenet, C., and H. Satou, H., Ohta, H., Hayashi, T., Jacquenet, C., and H.
He, "AAA and Admission Control Framework for He, "AAA and Admission Control Framework for
Multicasting", draft-ietf-mboned-multiaaa-framework-12 Multicasting", draft-ietf-mboned-multiaaa-framework-12
(work in progress), August 2010. (work in progress), August 2010.
[I-D.ietf-mboned-v4v6-mcast-ps]
Jacquenet, C., Boucadair, M., Lee, Y., Qin, J., Tsou, T.,
and Q. Sun, "IPv4-IPv6 Multicast: Problem Statement and
Use Cases", draft-ietf-mboned-v4v6-mcast-ps-00 (work in
progress), May 2012.
[I-D.ietf-softwire-multicast-prefix-option] [I-D.ietf-softwire-multicast-prefix-option]
Boucadair, M., Qin, J., Tsou, T., and X. Deng, "DHCPv6 Boucadair, M., Qin, J., Tsou, T., and X. Deng, "DHCPv6
Option for IPv4-Embedded Multicast and Unicast IPv6 Option for IPv4-Embedded Multicast and Unicast IPv6
Prefixes", draft-ietf-softwire-multicast-prefix-option-00 Prefixes", draft-ietf-softwire-multicast-prefix-option-01
(work in progress), March 2012. (work in progress), August 2012.
[I-D.jaclee-behave-v4v6-mcast-ps]
Jacquenet, C., Boucadair, M., Lee, Y., Qin, J., and T.
Tsou, "IPv4-IPv6 Multicast: Problem Statement and Use
Cases", draft-jaclee-behave-v4v6-mcast-ps-03 (work in
progress), October 2011.
[RFC2236] Fenner, W., "Internet Group Management Protocol, Version [RFC2236] Fenner, W., "Internet Group Management Protocol, Version
2", RFC 2236, November 1997. 2", RFC 2236, November 1997.
[RFC2473] Conta, A. and S. Deering, "Generic Packet Tunneling in [RFC5735] Cotton, M. and L. Vegoda, "Special Use IPv4 Addresses",
IPv6 Specification", RFC 2473, December 1998. BCP 153, RFC 5735, January 2010.
[RFC4604] Holbrook, H., Cain, B., and B. Haberman, "Using Internet
Group Management Protocol Version 3 (IGMPv3) and Multicast
Listener Discovery Protocol Version 2 (MLDv2) for Source-
Specific Multicast", RFC 4604, August 2006.
[RFC4608] Meyer, D., Rockell, R., and G. Shepherd, "Source-Specific [RFC6676] Venaas, S., Parekh, R., Van de Velde, G., Chown, T., and
Protocol Independent Multicast in 232/8", BCP 120, M. Eubanks, "Multicast Addresses for Documentation",
RFC 4608, August 2006. RFC 6676, August 2012.
Appendix A. Use Case: IPTV Appendix A. Use Case: IPTV
IPTV generally includes two categories of service offerings: IPTV generally includes two categories of service offerings:
o Video on Demand (VoD) that unicast video content to receivers. o Video on Demand (VoD) that unicast video content to receivers.
o Multicast live TV broadcast services. o Multicast live TV broadcast services.
Two players intervene in the delivery of this service: Two players intervene in the delivery of this service:
skipping to change at page 17, line 33 skipping to change at page 17, line 33
consequence, IPv4 service continuity MUST be guaranteed during the consequence, IPv4 service continuity MUST be guaranteed during the
transition period, including the delivery of multicast services such transition period, including the delivery of multicast services such
as Live TV Broadcasting to users. as Live TV Broadcasting to users.
Appendix B. Deployment Considerations Appendix B. Deployment Considerations
B.1. Other operational Modes B.1. Other operational Modes
B.1.1. MLD Querier with mAFTR Embedded B.1.1. MLD Querier with mAFTR Embedded
If mAFTR is embedded in the device that acts as a MLD Querier (as mAFTR can embed the MLD Querier function (as well as the PIMv6 DR)
well as the PIMv6 DR) connecting mB4, it should process the received for optimization. When mB4 sends MLD Report message to this mAFTR,
MLD Report message for the IPv4-embedded IPv6 group and send the the mAFTR should process the MLD Report message that contain IPv4-
corresponding PIMv4 Join message for the IPv4 multicast group address embedded IPv6 multicast group subscription information then send the
retrieved. corresponding PIMv4 Join message. (Figure 4)
+---------+ +---------+
---------| mAFTR |--------- ---------| mAFTR |---------
MLD |uPrefix64| PIMv4 MLD |uPrefix64| PIMv4
|mPreifx64| |mPreifx64|
+---------+ +---------+
Figure 4: MLD-PIMv4 Interworking Function Figure 4: MLD-PIMv4 Interworking Function
The locations of the mAFTR and how to make it deployed in both IPv4 Discussions about the location of the mAFTR capability and related
and IPv6 multicast networks in the context of ASM or SSM are out of ASM or SSM multicast design considerations are out of the scope of
the scope of this document. this document.
B.1.2. mAFTR embedded in DR B.1.2. mAFTR embedded in DR
If mAFTR is embedded in the device that acts as a DR connecting the If mAFTR is the DR of the original IPv4 source, it may simply use the
original IPv4 source, it will just need to use the uPrefix64 and uPrefix64 and mPrefix64 to build the IPv4-embedded IPv6 multicast
mPrefix64 to build the IPv4-embedded IPv6 multicast traffic, the traffic, the sending of PIMv4 Join message is not necessary.
sending of PIMv4 Join message is not necessary.
B.2. Older Version of Group Membership management Protocols B.2. Older Version of Group Membership management Protocols
Given the multiple versions of group membership management protocols, Given the multiple versions of group membership management protocols,
mismatch issues may be raised in the mB4 Function (refer to mismatch issues may be raised in the mB4 Function (refer to
Section 6.1). Section 6.1).
If IGMPv2 operates on the IPv4 receivers while MLDv2 operates on the If IGMPv2 operates on the IPv4 receivers while MLDv2 operates on the
MLD Querier, or if IGMPv3 operates on the IPv4 receivers while MLDv1 MLD Querier, or if IGMPv3 operates on the IPv4 receivers while MLDv1
operates on the MLD Querier, the issue mentioned above will be operates on the MLD Querier, the issue mentioned above will be
skipping to change at page 19, line 11 skipping to change at page 19, line 10
To optimize the usage of network resources in current deployments, To optimize the usage of network resources in current deployments,
all multicast streams are conveyed in the core network while only all multicast streams are conveyed in the core network while only
popular ones are continuously conveyed in the aggregation/access popular ones are continuously conveyed in the aggregation/access
network (static mode). Non-popular streams are conveyed in the network (static mode). Non-popular streams are conveyed in the
access network upon request (dynamic mode). Depending on the access network upon request (dynamic mode). Depending on the
location of the mAFTR in the network, two modes can be envisaged: location of the mAFTR in the network, two modes can be envisaged:
static and dynamic. static and dynamic.
o Static Mode: the mAFTR is configured to instantiate permanent (S6, o Static Mode: the mAFTR is configured to instantiate permanent (S6,
G6) and (*, G6) entries in its MRIBv6 using a pre-configured (S4, G6) and (*, G6) entries in its TIB6 using a pre-configured (S4,
G4) list. G4) list.
o Dynamic Mode: the instantiation and deletion of (S6, g6) or (*, o Dynamic Mode: the instantiation and deletion of (S6, g6) or (*,
G6) is triggered by the receipt of PIMv6 messages. G6) is triggered by the receipt of PIMv6 messages.
Authors' Addresses Authors' Addresses
Jacni Qin Jacni Qin
Cisco Cisco
Shanghai, Shanghai,
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