draft-ietf-softwire-dslite-multicast-16.txt   draft-ietf-softwire-dslite-multicast-17.txt 
Softwire WG M. Boucadair Softwire WG M. Boucadair
Internet-Draft Orange Internet-Draft Orange
Intended status: Standards Track C. Qin Intended status: Standards Track C. Qin
Expires: July 21, 2017 Cisco Expires: August 5, 2017 Cisco
C. Jacquenet C. Jacquenet
Orange Orange
Y. Lee Y. Lee
Comcast Comcast
Q. Wang Q. Wang
China Telecom China Telecom
January 17, 2017 February 1, 2017
Delivery of IPv4 Multicast Services to IPv4 Clients over an IPv6 Delivery of IPv4 Multicast Services to IPv4 Clients over an IPv6
Multicast Network Multicast Network
draft-ietf-softwire-dslite-multicast-16 draft-ietf-softwire-dslite-multicast-17
Abstract Abstract
This document specifies a solution for the delivery of IPv4 multicast This document specifies a solution for the delivery of IPv4 multicast
services to IPv4 clients over an IPv6 multicast network. The 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 an IPv6 multicast distribution tree to deliver IPv4 and uses an IPv6 multicast distribution tree to deliver IPv4
multicast traffic. The solution is particularly useful for the multicast traffic. The solution is particularly useful for the
delivery of multicast service offerings to DS-Lite serviced delivery of multicast service offerings to DS-Lite serviced
customers. customers.
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This Internet-Draft will expire on July 21, 2017. This Internet-Draft will expire on August 5, 2017.
Copyright Notice Copyright Notice
Copyright (c) 2017 IETF Trust and the persons identified as the Copyright (c) 2017 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
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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
1.1. Requirements Language . . . . . . . . . . . . . . . . . . 4 1.1. Requirements Language . . . . . . . . . . . . . . . . . . 4
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4
3. Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 3. Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
4. Solution Overview . . . . . . . . . . . . . . . . . . . . . . 5 4. Solution Overview . . . . . . . . . . . . . . . . . . . . . . 6
4.1. IPv4-Embedded IPv6 Prefixes . . . . . . . . . . . . . . . 6 4.1. IPv4-Embedded IPv6 Prefixes . . . . . . . . . . . . . . . 7
4.2. Multicast Distribution Tree Computation . . . . . . . . . 7 4.2. Multicast Distribution Tree Computation . . . . . . . . . 7
4.3. Multicast Data Forwarding . . . . . . . . . . . . . . . . 8 4.3. Multicast Data Forwarding . . . . . . . . . . . . . . . . 8
5. IPv4/IPv6 Address Mapping . . . . . . . . . . . . . . . . . . 8 5. IPv4/IPv6 Address Mapping . . . . . . . . . . . . . . . . . . 9
5.1. Prefix Assignment . . . . . . . . . . . . . . . . . . . . 8 5.1. Prefix Assignment . . . . . . . . . . . . . . . . . . . . 9
5.2. Multicast Address Translation Algorithm . . . . . . . . . 9 5.2. Multicast Address Translation Algorithm . . . . . . . . . 9
5.3. Textual Representation . . . . . . . . . . . . . . . . . 9 5.3. Textual Representation . . . . . . . . . . . . . . . . . 10
5.4. Examples . . . . . . . . . . . . . . . . . . . . . . . . 9 5.4. 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 . . . . . . . . . . . . . . . 12
6.5. Preserve the Scope . . . . . . . . . . . . . . . . . . . 12 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 Messages . . . . . . . . . . . . . . . . . 12 7.2. Processing PIM Messages . . . . . . . . . . . . . . . . . 13
7.3. Switching from Shared Tree to Shortest Path Tree . . . . 14 7.3. Switching from Shared Tree to Shortest Path Tree . . . . 14
7.4. Multicast Data Forwarding . . . . . . . . . . . . . . . . 14 7.4. Multicast Data Forwarding . . . . . . . . . . . . . . . . 14
7.5. Scope . . . . . . . . . . . . . . . . . . . . . . . . . . 14 7.5. Scope . . . . . . . . . . . . . . . . . . . . . . . . . . 14
8. Deployment Considerations . . . . . . . . . . . . . . . . . . 15 8. Deployment Considerations . . . . . . . . . . . . . . . . . . 15
8.1. Other Operational Modes . . . . . . . . . . . . . . . . . 15 8.1. Other Operational Modes . . . . . . . . . . . . . . . . . 15
8.1.1. The MLD Querier is Co-Located with the mAFTR . . . . 15 8.1.1. The IPv6 DR is Co-Located with the mAFTR . . . . . . 15
8.1.2. The DR is Co-Located with the mAFTR . . . . . . . . . 15 8.1.2. The IPv4 DR is Co-Located with the mAFTR . . . . . . 15
8.2. Load Balancing . . . . . . . . . . . . . . . . . . . . . 15 8.2. Load Balancing . . . . . . . . . . . . . . . . . . . . . 15
8.3. mAFTR Policy Configuration . . . . . . . . . . . . . . . 15 8.3. mAFTR Policy Configuration . . . . . . . . . . . . . . . 16
8.4. Static vs. Dynamic PIM Triggering . . . . . . . . . . . . 16 8.4. Static vs. Dynamic PIM Triggering . . . . . . . . . . . . 16
9. Security Considerations . . . . . . . . . . . . . . . . . . . 16 9. Security Considerations . . . . . . . . . . . . . . . . . . . 16
9.1. Firewall Configuration . . . . . . . . . . . . . . . . . 16 9.1. Firewall Configuration . . . . . . . . . . . . . . . . . 16
10. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 16 10. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 17
11. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 17 11. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 17
12. References . . . . . . . . . . . . . . . . . . . . . . . . . 17 12. References . . . . . . . . . . . . . . . . . . . . . . . . . 17
12.1. Normative References . . . . . . . . . . . . . . . . . . 17 12.1. Normative References . . . . . . . . . . . . . . . . . . 17
12.2. Informative References . . . . . . . . . . . . . . . . . 18 12.2. Informative References . . . . . . . . . . . . . . . . . 18
Appendix A. Use Case: IPTV . . . . . . . . . . . . . . . . . . . 19 Appendix A. Use Case: IPTV . . . . . . . . . . . . . . . . . . . 19
Appendix B. Older Versions of Group Membership Management Appendix B. Older Versions of Group Membership Management
Protocols . . . . . . . . . . . . . . . . . . . . . 19 Protocols . . . . . . . . . . . . . . . . . . . . . 20
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 20 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 20
1. Introduction 1. Introduction
DS-Lite [RFC6333] is an IPv4 address-sharing technique that enables DS-Lite [RFC6333] is an IPv4 address-sharing technique that enables
operators to multiplex public IPv4 addresses while provisioning only operators to multiplex public IPv4 addresses while provisioning only
IPv6 to users. A typical DS-Lite scenario is the delivery of an IPv4 IPv6 to users. A typical DS-Lite scenario is the delivery of an IPv4
service to an IPv4 user over an IPv6 network (denoted as a 4-6-4 service to an IPv4 user over an IPv6 network (denoted as a 4-6-4
scenario). [RFC6333] covers unicast services exclusively. scenario). [RFC6333] covers unicast services exclusively.
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Host portion of the MLD protocol: refers to the part of MLD that Host portion of the MLD protocol: refers to the part of MLD that
applies to all multicast address listeners (Section 6 of applies to all multicast address listeners (Section 6 of
[RFC3810]). As a reminder, MLD specifies separate behaviors for [RFC3810]). As a reminder, MLD specifies separate behaviors for
multicast address listeners (i.e., hosts or routers that listen to multicast address listeners (i.e., hosts or routers that listen to
multicast packets) and multicast routers. multicast packets) and multicast routers.
Router portion of the IGMP protocol: refers to the part of IGMP that Router portion of the IGMP protocol: refers to the part of IGMP that
is performed by multicast routers (Section 6 of [RFC3376]). is performed by multicast routers (Section 6 of [RFC3376]).
DR: refers to the Designated Router as defined in [RFC7761].
3. Scope 3. Scope
This document focuses only on the subscription to IPv4 multicast This document focuses only on the subscription to IPv4 multicast
groups and the delivery of IPv4-formatted content to IPv4 receivers groups and the delivery of IPv4-formatted content to IPv4 receivers
over an IPv6-only network. In particular, only the following case is over an IPv6-only network. In particular, only the following case is
covered: covered:
IPv4 receivers access IPv4 multicast contents over IPv6-only IPv4 receivers access IPv4 multicast contents over IPv6-only
multicast-enabled networks. multicast-enabled networks.
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scope matches the IPv4 multicast address used to synthesize an scope matches the IPv4 multicast address used to synthesize an
IPv4-embedded IPv6 multicast address. IPv4-embedded IPv6 multicast address.
An mAFTR MAY be configured to not preserve the scope when enforcing An mAFTR MAY be configured to not preserve the scope when enforcing
the address translation algorithm. the address translation algorithm.
8. Deployment Considerations 8. Deployment Considerations
8.1. Other Operational Modes 8.1. Other Operational Modes
8.1.1. The MLD Querier is Co-Located with the mAFTR 8.1.1. The IPv6 DR is Co-Located with the mAFTR
The mAFTR can embed the MLD Querier function (as well as the PIMv6 The mAFTR can embed the MLD Querier function (as well as the PIMv6
DR) for optimization purposes. When the mB4 sends a MLD Report DR) for optimization purposes. When the mB4 sends a MLD Report
message to this mAFTR, the mAFTR should process the MLD Report message to this mAFTR, the mAFTR should process the MLD Report
message that contains the IPv4-embedded IPv6 multicast group address message that contains the IPv4-embedded IPv6 multicast group address
and then send the corresponding PIMv4 Join message (Figure 4). and then send the corresponding PIMv4 Join message (Figure 4).
+---------+ +---------+
---------| mAFTR |--------- ---------| mAFTR |---------
MLD |uPrefix64| PIMv4 MLD |uPrefix64| PIMv4
|mPrefix64| |mPrefix64|
+---------+ +---------+
Figure 4: MLD-PIMv4 Interworking Function Figure 4: MLD-PIMv4 Interworking Function
Discussions about the location of the mAFTR capability and related Discussions about the location of the mAFTR capability and related
ASM or SSM multicast design considerations are out of the scope of ASM or SSM multicast design considerations are out of the scope of
this document. this document.
8.1.2. The DR is Co-Located with the mAFTR 8.1.2. The IPv4 DR is Co-Located with the mAFTR
If the mAFTR is co-located with the DR connected to the original IPv4 If the mAFTR is co-located with the IPv4 DR connected to the original
source, it may simply use the uPrefix64 and mPrefix64 prefixes to IPv4 source, it may simply use the uPrefix64 and mPrefix64 prefixes
build the IPv4-embedded IPv6 multicast packets, and the sending of to build the IPv4-embedded IPv6 multicast packets, and the sending of
PIMv4 Join messages becomes unnecessary. PIMv4 Join messages becomes unnecessary.
8.2. Load Balancing 8.2. Load Balancing
For robustness and load distribution purposes, several nodes in the For robustness and load distribution purposes, several nodes in the
network can embed the mAFTR function. In such case, the same IPv6 network can embed the mAFTR function. In such case, the same IPv6
prefixes (i.e., mPrefix64 and uPrefix64) and algorithm to build prefixes (i.e., mPrefix64 and uPrefix64) and algorithm to build
IPv4-embedded IPv6 addresses must be configured on those nodes. IPv4-embedded IPv6 addresses must be configured on those nodes.
8.3. mAFTR Policy Configuration 8.3. mAFTR Policy Configuration
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Dynamic Mode: the instantiation or withdrawal of (S6,G6) or (*,G6) Dynamic Mode: the instantiation or withdrawal of (S6,G6) or (*,G6)
entries is triggered by the receipt of PIMv6 messages. entries is triggered by the receipt of PIMv6 messages.
9. Security Considerations 9. Security Considerations
Besides multicast scoping considerations (see Section 6.5 and Besides multicast scoping considerations (see Section 6.5 and
Section 7.5), this document does not introduce any new security Section 7.5), this document does not introduce any new security
concern in addition to what is discussed in Section 5 of [RFC6052], concern in addition to what is discussed in Section 5 of [RFC6052],
Section 10 of [RFC3810] and Section 6 of [RFC7761]. Section 10 of [RFC3810] and Section 6 of [RFC7761].
Unlike solutions that map IPv4 multicast flows to IPv6 unicast flows,
this document does not exacerbate Denial-of-Service (DoS) attacks.
An mB4 SHOULD be provided with appropriate configuration information An mB4 SHOULD be provided with appropriate configuration information
to preserve the scope of a multicast message when mapping an IPv4 to preserve the scope of a multicast message when mapping an IPv4
multicast address into an IPv4-embedded IPv6 multicast address and multicast address into an IPv4-embedded IPv6 multicast address and
vice versa. vice versa.
9.1. Firewall Configuration 9.1. Firewall Configuration
The CPE that embeds the mB4 function 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.
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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 version mismatch issue will be operates on the MLD Querier, the version mismatch issue will be
encountered. To solve this problem, the mB4 should perform the encountered. To solve this problem, the mB4 should perform the
router portion of IGMP which is similar to the corresponding MLD router portion of IGMP which is similar to the corresponding MLD
version (IGMPv2 as of MLDv1, or IGMPv3 as of MLDv2) operating in the version (IGMPv2 as of MLDv1, or IGMPv3 as of MLDv2) operating in the
IPv6 domain. Then, the protocol interaction approach specified in IPv6 domain. Then, the protocol interaction approach specified in
Section 7 of [RFC3376] can be applied to exchange signaling messages Section 7 of [RFC3376] can be applied to exchange signaling messages
with the IPv4 receivers on which the different version of IGMP is with the IPv4 receivers on which the different version of IGMP is
operating. operating.
Noet that the support of IPv4 SSM requires to enable MLDv2 in the Note that the support of IPv4 SSM requires to enable MLDv2 in the
IPv6 network. IPv6 network.
Authors' Addresses Authors' Addresses
Mohamed Boucadair Mohamed Boucadair
Orange Orange
Rennes 35000 Rennes 35000
France France
Email: mohamed.boucadair@orange.com Email: mohamed.boucadair@orange.com
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