Requirements for the extension of the IGMP/MLD proxy functionality to support multiple upstream interfaces
draft-ietf-pim-multiple-upstreams-reqs-02
The information below is for an old version of the document.
| Document | Type | Active Internet-Draft (pim WG) | |
|---|---|---|---|
| Authors | Luis M. Contreras , Carlos J. Bernardos , Hitoshi Asaeda | ||
| Last updated | 2016-07-07 | ||
| Stream | Internet Engineering Task Force (IETF) | ||
| Formats | plain text htmlized pdfized bibtex | ||
| Stream | WG state | WG Document | |
| Document shepherd | (None) | ||
| IESG | IESG state | I-D Exists | |
| Consensus boilerplate | Unknown | ||
| Telechat date | (None) | ||
| Responsible AD | (None) | ||
| Send notices to | (None) |
draft-ietf-pim-multiple-upstreams-reqs-02
PIM Working Group LM. Contreras
Internet-Draft Telefonica
Intended status: Experimental CJ. Bernardos
Expires: January 8, 2017 Universidad Carlos III de Madrid
H. Asaeda
NICT
July 7, 2016
Requirements for the extension of the IGMP/MLD proxy functionality to
support multiple upstream interfaces
draft-ietf-pim-multiple-upstreams-reqs-02
Abstract
The purpose of this document is to define the requirements for a MLD
(for IPv6) or IGMP (for IPv4) proxy with multiple interfaces covering
a variety of applicability scenarios.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
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Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
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material or to cite them other than as "work in progress."
This Internet-Draft will expire on January 8, 2017.
Copyright Notice
Copyright (c) 2016 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
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to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of
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the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 2
3. Problem statement . . . . . . . . . . . . . . . . . . . . . . 3
4. Scenarios of applicability . . . . . . . . . . . . . . . . . 4
4.1. Fixed network scenarios . . . . . . . . . . . . . . . . . 5
4.1.1. Multicast wholesale offer for residential services . 5
4.1.1.1. Requirements . . . . . . . . . . . . . . . . . . 5
4.1.2. Multicast resiliency . . . . . . . . . . . . . . . . 5
4.1.2.1. Requirements . . . . . . . . . . . . . . . . . . 6
4.1.3. Load balancing for multicast traffic in the metro
segment . . . . . . . . . . . . . . . . . . . . . . . 6
4.1.3.1. Requirements . . . . . . . . . . . . . . . . . . 6
4.1.4. Network merging with different multicast services . . 6
4.1.4.1. Requirements . . . . . . . . . . . . . . . . . . 7
4.1.5. Summary of the requirements needed for fixed network
scenarios . . . . . . . . . . . . . . . . . . . . . . 7
4.2. Mobile network scenarios . . . . . . . . . . . . . . . . 8
5. Security Considerations . . . . . . . . . . . . . . . . . . . 8
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8
7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 9
8. References . . . . . . . . . . . . . . . . . . . . . . . . . 9
8.1. Normative References . . . . . . . . . . . . . . . . . . 9
8.2. Informative References . . . . . . . . . . . . . . . . . 9
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 9
1. Introduction
The aim of this document is to define the functionality that an IGMP/
MLD proxy with multiple upstream interfaces should have in order to
support different scenarios of applicability in both fixed and mobile
networks. This compatibility is needed in order to simplify node
functionality and to ensure an easier deployment of multicast
capabilities in all the use cases described in this document.
2. Terminology
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC2119 [RFC2119].
This document uses the terminology defined in RFC4605 [RFC4605].
Specifically, the definition of Upstream and Downstream interfaces,
which are reproduced here for completeness.
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Upstream interface: A proxy device's interface in the direction of
the root of the tree. Also called the "Host interface".
Downstream interface: Each of a proxy device's interfaces that is
not in the direction of the root of the tree. Also called the
"Router interfaces".
3. Problem statement
The concept of IGMP/MLD proxy with several upstream interfaces has
emerged as a way of optimizing (and in some cases enabling) service
delivery scenarios where separate multicast service providers are
reachable through the same access network infrastructure. Figure 1
presents the conceptual model under consideration.
downstream upstream
interface interface A
| |
| | _______________
| +-------+ v / \
| | O-------( Multicast Set 1 )
+----------+ v | IGMP/ | \_______________/
| Listener |------| MLD | _______________
+----------+ | Proxy | / \
| O-------( Multicast Set 2 )
+-------+ ^ \_______________/
|
|
upstream
interface B
Figure 1: Concept of IGMP/MLD proxy with multiple upstream interfaces
The current version of this document is focused on fixed network
scenarios. Applicability of IGMP/MLD proxies with multiple upstream
interfaces in mobile environments has been previously described in
RFC7287 [RFC7287]. Mobile network scenarios will be covered in
future versions of this document.
In the case of fixed networks, multicast wholesale services in a
competitive residential market require an efficient distribution of
multicast traffic from different operators or content providers, i.e.
the incumbent operator and a number of alternative providers, on the
network infrastructure of the former. Existing proposals are based
on the use of PIM routing from the metro/core network, and multicast
traffic aggregation on the same tree. A different approach could be
achieved with the use of an IGMP/MLD proxy with multiple upstream
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interfaces, each of them pointing to a distinct multicast router in
the metro/core border which is part of separated multicast trees deep
in the network. Figure 2 graphically describes this scenario.
downstream upstream
interface interface A
| |
| | _______________
| +--------+ v / \
| | Aggr. O-------( Multicast Set 1 )
| | Switch | \_______________/
+----+ v | | (e.g. from the Incumbent
| AN |-------| (IGMP | Operator)
+----+ | /MLD | _______________
(e.g. | Proxy) | / \
DSLAM | O-------( Multicast Set 2 )
/OLT) +--------+ ^ \_______________/
| (e.g. from an Alternative
| Provider)
|
upstream
interface B
Figure 2: Example of usage of an IGMP/MLD proxy with multiple
upstream interfaces in a fixed network scenario
Since those scenarios can motivate distinct needs in terms of IGMP/
MLD proxy functionality, it is necessary to consider a comprehensive
approach, looking at the possible scenarios, and establishing a
minimum set of requirements which can allow the operation of a
versatile IGMP/MLD proxy with multiple upstream interfaces as a
common entity to all of them (i.e., no different kinds of proxies
depending on the scenario, but a common proxy applicable to all the
potential scenarios).
4. Scenarios of applicability
Having multiple upstream interfaces creates a new decision space for
delivering the proper multicast content to the subscriber. Basically
it is now possible to implement channel-based or subscriber-based
upstream selection, according to mechanisms or policies that could be
defined for the multicast service provision.
This section describes in detail a number of scenarios of
applicability of an IGMP/MLD proxy with multiple upstream interfaces
in place. A number of requirements for the IGMP/MLD proxy
functionality are identified from those scenarios.
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4.1. Fixed network scenarios
Residential broadband users get access to multiple IP services
through fixed network infrastructures. End user's equipment is
connected to an access node, and the traffic of a number of access
nodes is collected in aggregation switches.
For the multicast service, the use of an IGMP/MLD proxy with multiple
upstream interfaces in those switches can provide service flexibility
in a lightweight and simpler manner if compared with PIM-routing
based alternatives.
4.1.1. Multicast wholesale offer for residential services
This scenario has been already introduced in the previous section,
and can be seen in Figure 2. There are two different operators, the
one operating the fixed network where the end user is connected
(e.g., typically an incumbent operator), and the one providing the
Internet service to the end user (e.g., an alternative Internet
service provider). Both can offer multicast streams that can be
subscribed by the end user, independently of which provider
contributes with the content.
Note that it is assumed that both providers offer distinct multicast
groups. However, more than one subscription to multicast channels of
different providers could take place simultaneously.
4.1.1.1. Requirements
o The IGMP/MLD proxy should be able to deliver multicast control
messages sent by the end user to the corresponding provider's
multicast router.
o The IGMP/MLD proxy should be able to deliver multicast control
messages sent by each of the providers to the corresponding end
user.
4.1.2. Multicast resiliency
In current PIM-based solutions, the resiliency of the multicast
distribution relays on the routing capabilities provided by protocols
like PIM and VRRP RFC5798 [RFC5798]. A simpler scheme could be
achieved by implementing different upstream interfaces on IGMP/MLD
proxies, providing path diversity through the connection to distinct
leaves of a given multicast tree.
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It is assumed that only one of the upstream interfaces is active in
receiving the multicast content, while the other is up and in standby
mode for fast switching.
4.1.2.1. Requirements
o The IGMP/MLD proxy should be able to deliver multicast control
messages sent by the end user to the corresponding active upstream
interface.
o The IGMP/MLD proxy should be able to deliver multicast control
messages received in the active upstream to the end users, while
ignoring the control messages of the standby upstream interface.
o The IGMP/MLD proxy should be able of rapidly switching from the
active to the standby upstream interface in case of network
failure, transparently to the end user.
4.1.3. Load balancing for multicast traffic in the metro segment
A single upstream interface in existing IGMP/MLD proxy functionality
typically forces the distribution of all the channels on the same
path in the last segment of the network. Multiple upstream
interfaces could naturally split the demand, alleviating the
bandwidth requirements in the metro segment.
4.1.3.1. Requirements
o The IGMP/MLD proxy should be able to deliver multicast control
messages sent by the end user to the corresponding multicast
router which provides the channel of interest.
o The IGMP/MLD proxy should be able to deliver multicast control
messages sent by each of the multicast routers to the
corresponding end user.
o The IGMP/MLD proxy should be able to decide which upstream
interface is selected for any new channel request according to
defined criteria (e.g., load balancing).
4.1.4. Network merging with different multicast services
In some network merging situations, the multicast services provided
before in each of the merged networks are maintained for the
respective customer base (usually in a temporal fashion until the
multicast service is redifined in a new single offer, but not
necessarily, or not in short term, e.g. because of commercial
agreements for each of the previous service offers).
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In order to assists that network merging situations, IGMP/MLD proxies
with multiple upstream interfaces can help in the transition
simplifying the service provision and facilitating service
continuity.
4.1.4.1. Requirements
o The IGMP/MLD proxy should be able to deliver multicast control
messages sent by the end user to the corresponding multicast
router which provides the channel of interest, according to the
service subscription.
o The IGMP/MLD proxy should be able to deliver multicast control
messages sent by each of the multicast routers to the
corresponding end user, according to the service subscription.
o The IGMP/MLD proxy should be able to decide which upstream
interface is selected for any new channel request according to
defined criteria (e.g., service subscription).
4.1.5. Summary of the requirements needed for fixed network scenarios
Following the analysis above, a number of different requirements can
be identified by the IGMP/MLD proxy to support multiple upstream
interfaces in fixed network scenarios. The following table
summarizes these requirements.
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+-----------------------------------------------+
| Fixed Network Scenarios |
+---------+-----------+-----------+-----------+-----------+
|Functio- | Multicast | Multicast | Load | Network |
|nality | Wholesale | Resiliency| Balancing | Merging |
+---------+-----------+-----------+-----------+-----------+
|Upstream | | | | |
|Control | X | X | X | X |
|Delivery | | | | |
+---------+-----------+-----------+-----------+-----------+
|Downstr. | | | | |
|Control | X | X | X | X |
|Delivery | | | | |
+---------+-----------+-----------+-----------+-----------+
|Active / | | | | |
|Standby | | X | | |
|Upstream | | | | |
+---------+-----------+-----------+-----------+-----------+
|Upstr i/f| | | | |
|selection| | | X | X |
|per group| | | | |
+---------+-----------+-----------+-----------+-----------+
|Upstr i/f| | | | |
|selection| | X | | |
|all group| | | | |
+---------+-----------+-----------+-----------+-----------+
Figure 3: Functionality needed on IGMP/MLD proxy with multiple
upstream interfaces per application scenario in fixed networks
4.2. Mobile network scenarios
To be done.
5. Security Considerations
All the security considerations in RFC4605 [RFC4605] are directly
applicable to this proposal. Apart from that, if proper mechanisms
(i.e., implementation practices) are in place for channel-based or
subscriber-based upstream interface selection, Denial of Service
attacks can be prevented.
6. IANA Considerations
To be completed
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7. Acknowledgements
The authors would like to thank (in alphabetical order) Thomas C.
Schmidt and Dirk von Hugo for their comments and suggestions.
8. References
8.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<http://www.rfc-editor.org/info/rfc2119>.
[RFC4605] Fenner, B., He, H., Haberman, B., and H. Sandick,
"Internet Group Management Protocol (IGMP) / Multicast
Listener Discovery (MLD)-Based Multicast Forwarding
("IGMP/MLD Proxying")", RFC 4605, DOI 10.17487/RFC4605,
August 2006, <http://www.rfc-editor.org/info/rfc4605>.
8.2. Informative References
[RFC5798] Nadas, S., Ed., "Virtual Router Redundancy Protocol (VRRP)
Version 3 for IPv4 and IPv6", RFC 5798,
DOI 10.17487/RFC5798, March 2010,
<http://www.rfc-editor.org/info/rfc5798>.
[RFC7287] Schmidt, T., Ed., Gao, S., Zhang, H., and M. Waehlisch,
"Mobile Multicast Sender Support in Proxy Mobile IPv6
(PMIPv6) Domains", RFC 7287, DOI 10.17487/RFC7287, June
2014, <http://www.rfc-editor.org/info/rfc7287>.
Authors' Addresses
Luis M. Contreras
Telefonica
Ronda de la Comunicacion, s/n
Sur-3 building, 3rd floor
Madrid 28050
Spain
Email: luismiguel.contrerasmurillo@telefonica.com
URI: http://people.tid.es/LuisM.Contreras/
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Carlos J. Bernardos
Universidad Carlos III de Madrid
Av. Universidad, 30
Leganes, Madrid 28911
Spain
Phone: +34 91624 6236
Email: cjbc@it.uc3m.es
URI: http://www.it.uc3m.es/cjbc/
Hitoshi Asaeda
National Institute of Information and Communications Technology
4-2-1 Nukui-Kitamachi
Koganei, Tokyo 184-8795
Japan
Email: asaeda@nict.go.jp
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