Mboned M. Abrahamsson
Internet-Draft T-Systems
Intended status: Best Current Practice T. Chown
Expires: January 3, 2019 Jisc
L. Giuliano
Juniper Networks, Inc.
T. Eckert
Huawei
July 2, 2018
Deprecating ASM for Interdomain Multicast
draft-acg-mboned-deprecate-interdomain-asm-02
Abstract
This document recommends deprecation of the use of Any-Source
Multicast (ASM) for interdomain multicast. It recommends the use of
Source-Specific Multicast (SSM) for interdomain multicast
applications, and that hosts and routers that are expected to handle
such applications fully support SSM. The recommendations in this
document do not preclude the continued use of ASM within a single
organisation or domain, and are especially easy to adopt when already
using the preferred ASM protocol options there (PIM-SM).
Requirements Language
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 "Key words for use in
RFCs to Indicate Requirement Levels" [RFC2119].
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on January 3, 2019.
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Copyright Notice
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document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
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described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Multicast routing protocols . . . . . . . . . . . . . . . . . 3
2.1. ASM routing protocols . . . . . . . . . . . . . . . . . . 4
2.2. SSM Routing protocols . . . . . . . . . . . . . . . . . . 5
3. Discussion . . . . . . . . . . . . . . . . . . . . . . . . . 5
3.1. Observations on ASM and SSM deployments . . . . . . . . . 5
3.2. Advantages of SSM for interdomain multicast . . . . . . . 6
4. Recommendations . . . . . . . . . . . . . . . . . . . . . . . 7
4.1. Deprecating use of ASM for interdomain multicast . . . . 7
4.2. Including network support for IGMPv3 / MLDv2 . . . . . . 8
4.3. Building application support for SSM . . . . . . . . . . 8
4.4. Preferring SSM applications intradomain . . . . . . . . . 9
4.5. Documenting common practices for SSM support in
applications. . . . . . . . . . . . . . . . . . . . . . . 9
4.6. Documenting an ASM/SSM protocol mapping mechanism . . . . 10
4.7. Not filtering ASM addressing between domains . . . . . . 10
4.8. Not precluding Intradomain ASM . . . . . . . . . . . . . 10
5. Congestion Control Considerations . . . . . . . . . . . . . . 11
6. Security Considerations . . . . . . . . . . . . . . . . . . . 11
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 11
8. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 11
9. References . . . . . . . . . . . . . . . . . . . . . . . . . 11
9.1. Normative References . . . . . . . . . . . . . . . . . . 11
9.2. Informative References . . . . . . . . . . . . . . . . . 13
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 14
1. Introduction
IP Multicast has been deployed in various forms, within private
networks, the wider Internet, and federated networks such as national
or regional research networks. While a number of service models have
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been published, and in many cases revised over time, there has been
no strong recommendation made by the IETF on the appropriateness of
those models to certain scenarios, even though vendors and
federations have often made such recommendations.
This document addresses this gap by making a BCP-level recommendation
to deprecate the use of ASM for interdomain multicast, leaving SSM as
the remaining interdomain mode of multicast. This recommendation
thus also implicitly states that all hosts and routers that are
expected to support interdomain multicast applications fully support
SSM.
This document does not make any statement on the use of ASM within a
single domain or organisation, and therefore does not preclude its
use. Indeed, there are application contexts for which ASM is
currently still widely considered well-suited within a single domain.
The main issue in most cases with moving to SSM is application
support. Many applications will first get used intradomain but only
later interdomain. Therefore, this document recommends making
applications support SSM, even when they are initially meant to be
just used intradomain. As explained below, SSM applications are
readily compatible with existing intradomain ASM deployments that
follow the current IETF standard protocol recommendations.
2. Multicast routing protocols
The general IP multicast service model [RFC1112] is that sender(s)
send to a multicast group address, receivers express an interest in
traffic sent to a given multicast group address, and that routers use
multicast routing protocols to determine how to deliver traffic from
the sender(s) to the receivers.
Two high-level flavours of this service model have evolved over time.
In Any-Source Multicast (ASM), any number of sources may transmit
multicast packets, and those sources may come and go over the course
of a multicast session without being known a priori. In ASM,
receivers express interest only in a given multicast group address,
and the multicast routing protocol facilitates source discovery at
the network layer. ASM is simply the name given to the 1989 RFC1112
IP Multicast model when in around 2000 the idea for the alternative
SSM model was taking shape: In Source-Specific Multicast (SSM) the
specific source(s) that may send traffic to the group are known in
advance by the receivers, or may be determined during a session,
typically through an out-of-band protocol sitting above the network
layer. Thus in SSM, receivers express interest in both a multicast
group address and specific associated source address(es).
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IANA has reserved specific ranges of IPv4 and IPv6 address space for
multicast addressing. Guidelines for IPv4 multicast address
assignments can be found in [RFC5771], while guidelines for IPv6
multicast address assignments can be found in [RFC2375] and
[RFC3307]. The IPv6 multicast address format is described in
[RFC4291].
2.1. ASM routing protocols
The most commonly deployed ASM routing protocol is Protocol
Independent Multicast - Sparse Mode, or PIM-SM, as detailed in
[RFC7761]. PIM-SM, as the name suggests, was designed to be used in
scenarios where the subnets with receivers are sparsely distributed
throughout the network. Because it does not know sender addresses in
advance, PIM-SM uses the concept of a Rendezvous Point (RP) to 'marry
up' senders and receivers, and all routers in a PIM-SM domain are
configured to use specific RP(s), either explicitly or through
dynamic RP discovery protocols.
To enable PIM-SM to work between multiple domains, i.e., to allow an
RP in one domain to learn the existence of a source in another
domain, an inter-RP signalling protocol known as Multicast Source
Discovery Protocol (MSDP) [RFC3618] is used. Deployment scenarios
for MSDP are given in [RFC4611]. MSDP has remained an Experimental
protocol since its publication in 2003. One core reason for this is
the need to flood information about all active sources for all active
applications to the RPs in all the domains in an MSDP peering mesh -
even if there is no receiver for a given application in a domain.
This is the key scalability and security issue with MSDP and also the
reason why it was not extended to support IPv6.
To this day, there is no IETF Proposed Standard level interdomain
solution for IPv4 ASM multicast because MSDP was the "best" component
for the interdomain discovery problem, and it stayed Experimental.
Other protocol options where investigated at the same time but did
achieve at most achieve IETF informational status and are now
historic (e.g: [RFC3913]).
Due to the availability of more bits in an IPv6 address than in IPv4,
an IPv6-specific mechanism was able to be designed in support of
interdomain ASM with PIM-SM. Embedded-RP [RFC3956] allows routers
supporting the protocol to determine the RP for the group without any
prior configuration or discovery protocols, simply by observing the
unicast RP address that is embedded (included) in the IPv6 multicast
group address. Embedded-RP allows PIM-SM operation across any IPv6
network (intradomain but especially interdomain) in which there is an
end-to-end path of routers supporting the mechanism.
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2.2. SSM Routing protocols
SSM is detailed in [RFC4607]. It is in effect a subset of PIM-SM
where no RP is used. Note that there is no separate document for
PIM-SSM, it just leverages a subset of [RFC7761].
PIM-SSM expects that sender source address(es) are known in advance
by receivers; i.e., a given source's IP address is known (by some out
of band mechanism), and thus the receiver's router can send a PIM
JOIN directly towards the sender, without needing to use an RP.
IPv4 addresses in the 232/8 (232.0.0.0 to 232.255.255.255) range are
designated as source-specific multicast (SSM) destination addresses
and are reserved for use by source-specific applications and
protocols. See [RFC4607]. For IPv6, the address prefix FF3x::/32 is
reserved for source-specific multicast use.
3. Discussion
3.1. Observations on ASM and SSM deployments
In enterprise and campus scenarios, ASM in the form of PIM-SM is
likely the most commonly deployed multicast protocol and has
generally replaced PIM-DM [RFC3973], which is an IETF Experimental
category RFC, while PIM-SM is full Internet Standard. The
configuration and management of an RP (even with RP redundancy)
within a single domain is well understood operational practice.
However, if interworking with external PIM domains is needed in IPv4
multicast deployments, interdomain MSDP is required to exchange
information about sources between domain RPs. The problems with this
use of MSDP are as explained above. They are the problems that make
MSDP an Experimental protocol, and that make it (in these
deployments) a complex and fragile protocol to administer and
troubleshoot (flooding RPF rules, state attack protection, undesired
source filtering, ...).
PIM-SM is a general purpose protocol that can handle all use cases.
In particular, it was designed for cases such as videoconferencing
where multiple sources may come and go during a multicast session.
But for cases where a single, persistent source for a group is used,
and receivers can be configured to know of that source, PIM-SM has
unnecessary complexity. In these applications it is typically only
necessary to extend the configuration or signaling for the IP
multicast group to be used with the additional information on the IP
multicast source to be used. There are also various techniques to
use a single logical "anycast" source address supported by two or
more redundant senders to give additional reliability for SSM, and to
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offer simpler deployment by using that address as a "static"/"well-
known" address.
As explained above, MSDP was not taken forward to IPv6. Instead, the
proposed interdomain ASM solution for PIM-SM with IPv6 is Embedded-
RP, which allows the RP address for a multicast group to be embedded
in the group address, making RP discovery automatic, if all routers
on the path between a receiver and a sender support the protocol.
Embedded-RP can support lightweight ad-hoc deployments. However, it
relies on a single RP for an entire group that could only be made
resilient within one domain. While this approach solves the MSDP
issues, it does not solve the problem of unauthorised sources sending
traffic to ASM multicast groups; this security issues is one of
biggest problem of interdomain multicast. Embedded-RP was run
successfully between European and US academic networks during the
6NET project in 2004/05. Its usage generally remains constrained to
academic networks.
As stated in RFC 4607, SSM is particularly well-suited to
dissemination-style applications with one or more senders whose
identities are known (by some mechanism) before the application
starts running - or applications that have some existing signaling
indicating multicast groups, where the additional source address can
easily be added - for example electronic programming guide signalling
in IPTV applications. PIM-SSM is therefore very well-suited to
applications such as classic linear broadcast TV over IP.
SSM requires applications, host operating systems and their subnet
routers using it to support the new(er) IGMPv3 [RFC3376] and MLDv2
[RFC3810] protocols. While delayed delivery of support in some OSes
has meant that adoption of SSM has been slower than might have been
expected, or hoped, and was a historical reason to use ASM rather
than SSM, support for IGMPv3 and MLDv2 has become widespread in
common OSes for several years (Windows, MacOS, Linux/Android).
3.2. Advantages of SSM for interdomain multicast
A significant benefit of SSM is its reduced complexity through
eliminating the network-based source discovery required in ASM. This
means there are no RPs, shared trees, Shortest Path Tree (SPT)
switchovers, PIM registers, MSDP, or data-driven state creation
elements to support, or any requirement to run dynamic RP discovery
and redundancy signaling protocols such as BSR. SSM is really just a
small subset of PIM-SM, alongside the integration with IGMPv3 / MLDv2
where the source address signaled from the receiver is immediately
used to create (S,G) state. Eliminating network-based source
discovery for interdomain multicast means the vast majority of the
complexity issues go away.
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This reduced complexity makes SSM radically simpler to manage,
troubleshoot and operate, particularly for network backbone
operators, and this is the main operator motivation for the
recommendation to deprecate the use of ASM in interdomain scenarios.
Note that SSM operation is all standardised in PIM-SM (RFC7761).
There is no separate specification for PIM-SSM.
RFC 4607 details many benefits of SSM, including:
"Elimination of cross-delivery of traffic when two sources
simultaneously use the same source-specific destination address;
Avoidance of the need for inter-host coordination when choosing
source-specific addresses, as a consequence of the above;
Avoidance of many of the router protocols and algorithms that are
needed to provide the ASM service model."
Further discussion can also be found in [RFC3569].
SSM is considered more secure in that it supports access control,
i.e. you only get packets from the sources you explicitly ask for, as
opposed to ASM where anyone can decide to send traffic to a PIM-SM
group address. This topic is expanded upon in [RFC4609].
4. Recommendations
4.1. Deprecating use of ASM for interdomain multicast
This document recommends that the use of ASM is deprecated for
interdomain multicast, and thus implicitly that hosts and routers
that are expected to support such interdomain applications fully
support SSM and its associated protocols. Best current practices for
deploying interdomain multicast using SSM are documented in
[RFC8313].
The recommendation applies to the use of ASM between domains where
either MSDP (IPv4) or Embedded-RP (IPv6) is used for sharing
knowledge of remote sources (MSDP) or RPs (Embedded-RP).
This document also recommends against the interdomain use of PIM-SM
with a (potentially redundant) RP, where multicast tunnels are used
between domains.
An interdomain use of ASM multicast in the context of this document
is primarily one where PIM-SM for ASM, e.g., with RPs/MSDP/Embedded-
RP, is run on routers operated by two or more separate operational
entities (domains, organisations).
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The more inclusive interpretation of this recommendation is that it
also extends to the case where PIM may only be operated in a single
operator domain, but where user hosts or non-PIM network edge devices
are under different operator control. A typical example of this case
is an SP providing IPTV (single operator domain for PIM) to
subscribers operating an IGMP proxy home gateway and IGMPv3/MLDv2
hosts (computer, tablets, set-top boxes).
While MSDP is an Experimental category IETF standard, this document
does not propose making MSDP Historic, given its use may be desirable
for intradomain multicast use cases (e.g., RP redundancy
intradomain). This may change in future documents should a successor
to MSDP for intradomain RP redundancy ([RFC4610]) be defined to add
better support for some currently missing operational requirements.
4.2. Including network support for IGMPv3 / MLDv2
This document recommends that all host and router platforms
supporting multicast, and any security appliances that may handle
multicast traffic, support IGMPv3 [RFC3376] and MLDv2 [RFC3810]
(based on the version IP they intend to support). The updated IPv6
Node Requirements RFC [I-D.ietf-6man-rfc6434-bis] states that MLDv2
support is a MUST in all implementations. Such support is already
widespread in common host and router platforms.
Further guidance on IGMPv3 and MLDv2 is given in [RFC4604].
It is sometimes desirable to limit the propagation of multicast
messages in a layer 2 network, typically through a layer 2 switch
device. In such cases multicast snooping can be used, by which the
switch device observes the IGMP/MLD traffic passing through it, and
then attempts to make intelligent decisions about on which physical
ports it should forward multicast. Typically, ports that have not
expressed an interest in receiving multicast for a given group would
not have traffic for that group forwarded through them. Such
snooping capability should therefore support IGMPv3 and MLDv2. There
is further discussion in [RFC4541].
4.3. Building application support for SSM
There is a wide range of applications today that only support ASM
(mostly for historic reasons), whether as software packages, or code
embedded in devices such as set-top boxes.
The recommendation to use SSM for interdomain multicast means that
applications should use SSM, and operate correctly in an SSM
environment, triggering IGMPv3/MLDv2 messages to signal use of SSM.
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It is often thought that ASM is required for multicast applications
where there are multiple sources. However, RFC 4607 also describes
how SSM can be used instead of PIM-SM for multi-party applications:
"SSM can be used to build multi-source applications where all
participants' identities are not known in advance, but the multi-
source "rendezvous" functionality does not occur in the network
layer in this case. Just like in an application that uses unicast
as the underlying transport, this functionality can be implemented
by the application or by an application-layer library."
Given all common OSes support SSM, it is then down to the programming
language and APIs used as to whether the necessary SSM APIs are
available. SSM support became first ubiquitous for C/C++/Python, and
key exceptions today include websockets used in web-browser based
applications (see e.g.: https://github.com/nodejs/node/pull/15735/
files introducing SSM support there in 2017).
Some useful considerations for multicast applications can still be
found in the relatively old [RFC3170].
4.4. Preferring SSM applications intradomain
If feasible, it is recommended to make applications use SSM, even if
they are initially only meant to be used in intradomain environments
supporting ASM. Because PIM-SSM is a subset of PIM-SM, it should be
possible to readily make existing intradomain PIM-SM networks
compatible with SSM application receivers, therefore allowing
continued use of an existing ASM PIM-SM deployment in a network with
no or very little changes. SSM's benefits of simplified address
management and significantly reduced operational complexity apply
equally to intradomain use.
However, for some applications it may be prohibitively difficult to
add support for signaling of source IP addresses into the
application.
4.5. Documenting common practices for SSM support in applications.
Currently, there is no good document summarising best current
practices to convert ASM applications into SSM applications, or how
to most easily support SSM in greenfield application designs. This
would be useful guidance for the IETF to work on.
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4.6. Documenting an ASM/SSM protocol mapping mechanism
In the case of existing ASM applications that cannot readily be
ported to SSM, it may be possible to use some form of protocol
mapping, i.e., to have a mechanism to translate a (*,G) join or leave
to a (S,G) join or leave, for a specific source, S. The general
challenge in performing such mapping is determining where the
configured source address, S, comes from.
There are existing vendor-specific mechanisms deployed that achieve
this function, but none are documented in IETF documents. This
appears to be a useful area for the IETF to work on, but it should be
noted that any such effort would only be an interim transition
mechanism, and such mappings do not remove the requirement for
applications to be allocated ASM group addresses for the
communications.
The reason why these mechanisms should not be considered a long-term
solution is because they introduce network operator management work,
and need some form of address management, both of which are not
required in SSM.
4.7. Not filtering ASM addressing between domains
A key benefit of SSM is that a multicast application does not need to
be allocated a specific multicast group by the network, rather as SSM
is inherently source-specific, it can use any group address, G, in
the reserved range of IPv4 or IPv6 SSM addresses for its own source
address, S.
In principle, if interdomain ASM is deprecated, backbone operators
could begin filtering the ranges of group addresses used by ASM. In
practice, this is not recommended given there will be a transition
period from ASM to SSM, where some form of ASM-SSM mappings may be
used, and filtering may preclude such operations.
4.8. Not precluding Intradomain ASM
The use of ASM within a single multicast domain, such as a campus or
enterprise, with an RP for the site, is still relatively common
today. There are even global enterprise networks that have
successfully been using PIM-SM for many years. The operators of such
networks most often use Anycast-RP [RFC4610] or MSDP for RP
resilience, at the expense of the extra complexity in managing that
configuration. These existing practices are unaffected by this
document.
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This document does not preclude continued use of ASM in the
intradomain scenario. If an organisation, or AS, wishes to use
multiple multicast domains within its own network border, that is a
choice for that organisation to make, and it may then use MSDP or
Embedded-RP internally within its own network.
5. Congestion Control Considerations
Traffic over non-controlled networks, which most interdomain paths
are, must support congestion control. This is achievable with rate
adaptation, layered codecs, circuit breakers and/or other appropriate
mechanisms. See [RFC8085].
6. Security Considerations
This document adds no new security considerations. It instead
removes security issues incurred by interdomain ASM with PIM-SM/MSDP:
infrastructure control plane attacks and application and bandwidth/
congestion attacks from unauthorised sources sending to ASM multicast
groups. RFC 4609 describes the additional security benefits of using
SSM instead of ASM.
7. IANA Considerations
This document makes no request of IANA.
Note to RFC Editor: this section may be removed upon publication as
an RFC.
8. Acknowledgments
The authors would like to thank members of the IETF mboned WG for
discussions on the content of this document, with specific thanks to
the following people for their contributions to the document: Hitoshi
Asaeda, Dale Carder, Jake Holland, Albert Manfredi, Mike McBride, Per
Nihlen, Greg Shepherd, James Stevens, Stig Venaas, Nils Warnke, and
Sandy Zhang.
9. References
9.1. Normative References
[RFC1112] Deering, S., "Host extensions for IP multicasting", STD 5,
RFC 1112, DOI 10.17487/RFC1112, August 1989,
<https://www.rfc-editor.org/info/rfc1112>.
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[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>.
[RFC3307] Haberman, B., "Allocation Guidelines for IPv6 Multicast
Addresses", RFC 3307, DOI 10.17487/RFC3307, August 2002,
<https://www.rfc-editor.org/info/rfc3307>.
[RFC3376] Cain, B., Deering, S., Kouvelas, I., Fenner, B., and A.
Thyagarajan, "Internet Group Management Protocol, Version
3", RFC 3376, DOI 10.17487/RFC3376, October 2002,
<https://www.rfc-editor.org/info/rfc3376>.
[RFC3810] Vida, R., Ed. and L. Costa, Ed., "Multicast Listener
Discovery Version 2 (MLDv2) for IPv6", RFC 3810,
DOI 10.17487/RFC3810, June 2004,
<https://www.rfc-editor.org/info/rfc3810>.
[RFC3956] Savola, P. and B. Haberman, "Embedding the Rendezvous
Point (RP) Address in an IPv6 Multicast Address",
RFC 3956, DOI 10.17487/RFC3956, November 2004,
<https://www.rfc-editor.org/info/rfc3956>.
[RFC4291] Hinden, R. and S. Deering, "IP Version 6 Addressing
Architecture", RFC 4291, DOI 10.17487/RFC4291, February
2006, <https://www.rfc-editor.org/info/rfc4291>.
[RFC4607] Holbrook, H. and B. Cain, "Source-Specific Multicast for
IP", RFC 4607, DOI 10.17487/RFC4607, August 2006,
<https://www.rfc-editor.org/info/rfc4607>.
[RFC4610] Farinacci, D. and Y. Cai, "Anycast-RP Using Protocol
Independent Multicast (PIM)", RFC 4610,
DOI 10.17487/RFC4610, August 2006,
<https://www.rfc-editor.org/info/rfc4610>.
[RFC5771] Cotton, M., Vegoda, L., and D. Meyer, "IANA Guidelines for
IPv4 Multicast Address Assignments", BCP 51, RFC 5771,
DOI 10.17487/RFC5771, March 2010,
<https://www.rfc-editor.org/info/rfc5771>.
[RFC7761] Fenner, B., Handley, M., Holbrook, H., Kouvelas, I.,
Parekh, R., Zhang, Z., and L. Zheng, "Protocol Independent
Multicast - Sparse Mode (PIM-SM): Protocol Specification
(Revised)", STD 83, RFC 7761, DOI 10.17487/RFC7761, March
2016, <https://www.rfc-editor.org/info/rfc7761>.
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9.2. Informative References
[RFC2375] Hinden, R. and S. Deering, "IPv6 Multicast Address
Assignments", RFC 2375, DOI 10.17487/RFC2375, July 1998,
<https://www.rfc-editor.org/info/rfc2375>.
[RFC3170] Quinn, B. and K. Almeroth, "IP Multicast Applications:
Challenges and Solutions", RFC 3170, DOI 10.17487/RFC3170,
September 2001, <https://www.rfc-editor.org/info/rfc3170>.
[RFC3569] Bhattacharyya, S., Ed., "An Overview of Source-Specific
Multicast (SSM)", RFC 3569, DOI 10.17487/RFC3569, July
2003, <https://www.rfc-editor.org/info/rfc3569>.
[RFC3618] Fenner, B., Ed. and D. Meyer, Ed., "Multicast Source
Discovery Protocol (MSDP)", RFC 3618,
DOI 10.17487/RFC3618, October 2003,
<https://www.rfc-editor.org/info/rfc3618>.
[RFC3913] Thaler, D., "Border Gateway Multicast Protocol (BGMP):
Protocol Specification", RFC 3913, DOI 10.17487/RFC3913,
September 2004, <https://www.rfc-editor.org/info/rfc3913>.
[RFC3973] Adams, A., Nicholas, J., and W. Siadak, "Protocol
Independent Multicast - Dense Mode (PIM-DM): Protocol
Specification (Revised)", RFC 3973, DOI 10.17487/RFC3973,
January 2005, <https://www.rfc-editor.org/info/rfc3973>.
[RFC4541] Christensen, M., Kimball, K., and F. Solensky,
"Considerations for Internet Group Management Protocol
(IGMP) and Multicast Listener Discovery (MLD) Snooping
Switches", RFC 4541, DOI 10.17487/RFC4541, May 2006,
<https://www.rfc-editor.org/info/rfc4541>.
[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, DOI 10.17487/RFC4604,
August 2006, <https://www.rfc-editor.org/info/rfc4604>.
[RFC4609] Savola, P., Lehtonen, R., and D. Meyer, "Protocol
Independent Multicast - Sparse Mode (PIM-SM) Multicast
Routing Security Issues and Enhancements", RFC 4609,
DOI 10.17487/RFC4609, October 2006,
<https://www.rfc-editor.org/info/rfc4609>.
Abrahamsson, et al. Expires January 3, 2019 [Page 13]
Internet-Draft Deprecating Interdomain ASM July 2018
[RFC4611] McBride, M., Meylor, J., and D. Meyer, "Multicast Source
Discovery Protocol (MSDP) Deployment Scenarios", BCP 121,
RFC 4611, DOI 10.17487/RFC4611, August 2006,
<https://www.rfc-editor.org/info/rfc4611>.
[RFC8085] Eggert, L., Fairhurst, G., and G. Shepherd, "UDP Usage
Guidelines", BCP 145, RFC 8085, DOI 10.17487/RFC8085,
March 2017, <https://www.rfc-editor.org/info/rfc8085>.
[RFC8313] Tarapore, P., Ed., Sayko, R., Shepherd, G., Eckert, T.,
Ed., and R. Krishnan, "Use of Multicast across Inter-
domain Peering Points", BCP 213, RFC 8313,
DOI 10.17487/RFC8313, January 2018,
<https://www.rfc-editor.org/info/rfc8313>.
[I-D.ietf-6man-rfc6434-bis]
Chown, T., Loughney, J., and T. Winters, "IPv6 Node
Requirements", draft-ietf-6man-rfc6434-bis-08 (work in
progress), March 2018.
Authors' Addresses
Mikael Abrahamsson
T-Systems
Stockholm
Sweden
Email: mikael.abrahamsson@t-systems.se
Tim Chown
Jisc
Lumen House, Library Avenue
Harwell Oxford, Didcot OX11 0SG
United Kingdom
Email: tim.chown@jisc.ac.uk
Lenny Giuliano
Juniper Networks, Inc.
2251 Corporate Park Drive
Hemdon, Virginia 20171
United States
Email: lenny@juniper.net
Abrahamsson, et al. Expires January 3, 2019 [Page 14]
Internet-Draft Deprecating Interdomain ASM July 2018
Toerless Eckert
Futurewei Technologies Inc.
2330 Central Expy
Santa Clara 95050
USA
Email: tte+ietf@cs.fau.de
Abrahamsson, et al. Expires January 3, 2019 [Page 15]