DMM Working Group Kyoungjae Sun
Internet Draft Younghan Kim
Intended status: Informational Soongsil University
Expires: April 2017 October 31, 2016
Multicast Anchoring in DMM
draft-kjsun-dmm-multicast-anchoring-04.txt
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Abstract
In this draft, we define multicast support functions in a
Distributed Mobility Management (DMM) environment. Based on the
decomposed mobility management functions in [RFC7429], each defined
multicast support function can be located and operated with DMM
functions.
Table of Contents
1. Introduction ................................................ 2
2. Conventions and Terminology ................................. 3
3. Multicast Support Functions in DMM .......................... 3
3.1. Multicast Anchoring Function (Multicast AF) ............ 3
3.2. Multicast Group Management Function (Multicast GM) ..... 4
3.3. Multicast Forwarding Management Function (Multicast FM). 5
4. Deploying Multicast Functions into Current Approaches ....... 5
4.1. Distributed AM, LM, and FM : All-in-One ................ 6
4.2. Distributed AF-DP, LM and FM with centralized AF-CP .... 6
4.3. Distributed AF-DP and FM-DP with centralized AF-CP, LM,
and FM-CP ............................................. 6
5. Security Considerations ..................................... 6
6. IANA Considerations ......................................... 6
7. References .................................................. 7
7.1. Normative References ................................... 7
7.2. Informative References ................................. 8
8. Acknowledgments ............................................. 8
1. Introduction
Based on [RFC7333], a multicast solution in Distributed Mobility
Management (DMM) should be considered early in the process of
designing protocol and deployment models. Multicast support in DMM
should avoid inefficient methods, such as non-optimal forwarding or
tunnel convergence.
To support IP multicasting, we need several functions: a multicast
routing protocol, membership management, etc. When we consider
multicast support in DMM, we should determine how efficiently these
functions can be operated with the mobility management functions in
DMM. Possible use cases are already described in [Use Case for
Multicast DMM]. However, since current DMM research considers
control/data separation and functional decomposition, we need to
define multicast support functions following decomposed DMM anchor
functions and operate with them.
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In this draft, we define multicast mobility management functions
that enable us to deploy the DMM functions defined in [RFC7429]. We
define multicast mobility management functions in a similar way
because it is easier to deploy multicast mobility management
functions with DMM functions.
2. Conventions and 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 RFC-2119 [RFC2119].
This document uses the terminology defined in [RFC5213], [RFC3810],
and [RFC4601]. New entities are defined by relying on the DMM
functions specified in [RFC7429]:
1. Anchoring Function (AF) is an allocation to a mobile node of an
IP address (e.g. Home Address (HoA))) or prefix (e.g. Home Network
Prefix (HNP)), topologically anchored by the advertising node.
2. Internetwork Location Management (LM) function manages and keeps
track of the internetwork location of an Mobile Node (MN). The
location information may be a binding of the advertised IP
address/prefix (e.g. HoA or HNP) to the MN's IP routing address, or
it may be a binding of a node that can forward packets destined for
the MN.
3. Forwarding Management (FM) function intercepts and forwards a
packet to/from the IP address/prefix assigned to the MN based on the
internetwork location information, either to the destination or to
some other network element that knows how to forward the packets to
their destinations.
3. Multicast Support Functions in DMM
In this chapter, we define functions to support multicasting in DMM
environment. The multicast support of previous mobility management
schemes (e.g., MIP and PMIP) deployed multicast router or MLD proxy
functions into their mobility entities (e.g., HA, LMA, and MAG).
According to the decomposition of previous mobility management
functions and considering the separation of the control and data
planes, a multicast support function also could be decompose into
several functions.
3.1. Multicast Anchoring Function (Multicast AF)
The multicast AF is defined as the anchoring point for multicast
subscribers in DMM domain. It means that all multicast traffic
from/to the DMM domain should be forwarded through the multicast AF.
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Even if the multicast AF is anchor point for multicast traffic, it
does not mean that it is anchor point for unicast traffic. In other
words, this function could be deployed separately with the DMM AF
(e.g. MTMA solution in [RFC7028]), or combined with the DMM AF
(e.g. LMA in [RFC6224]). The multicast AF function provides
connectivity to the multicast infrastructure out of the DMM domain.
With the multicast AF, the network entity may be part of multicast
tree. That is, multicast AFs have a Tree Information Base (TIB). It
could be act role of MLD proxy function which generate MLD
membership report or user-defined subset in the its upstream
interface. In addition, the multicast AF acts as MLD Querier of
other MLD proxy instances located in DMM.
To support multicast listeners, the multicast AF collects MLD report
messages from mobile nodes or other entities (e.g. MLD proxy defined
in [RFC4605]). To provide an appropriate multicast subscription, the
multicast AF should join/prune multicast channels based on MLD
reports from the mobile nodes. To support the multicast sender, this
function forwards the source information of the sender to the
Rendezvous Point (RP) in multicast infrastructure.
The multicast AF could be separated into control-plane function and
data-plane function. In that case, the multicast AF Control Plane
(multicast AF-CP) is responsible of managing multicast tree
information and sharing source information through multicast
infrastructure. In other words, the multicast AF-CP acts as MLD
Querier for the DMM domain and MLD proxy for the multicast
infrastructure. For that, the multicast AF-CP maintains multicast
forwarding states at its corresponding downstream interface and
aggregated multicast membership states at its upstream interface.
The multicast Data Plane (multicast AF-DP) is responsible of
anchoring multicast data packets destined to the appropriate
subscribers in the DMM domain. It should forward multicast traffic
according to the multicast forwarding rules configured by the
multicast AF-CP.
3.2. Multicast Group Management Function (Multicast GM)
The multicast GM function is partially acts as MLD proxy which
manages multicast subscriber information. According to [RFC4605],
the MDL proxy devices maintain the membership database, which
considers merging all subscriptions on the downstream interface. The
membership database is presented a set of membership records,
multicast addresses, filter modes and source lists. The multicast GM
can maintain this database to support maintaining multicast
subscribers and multicast sources. For that, the multicast AF
function should create/delete/update membership database in the
multicast GM when the mobile node join or leave multicast channel.
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Especially the multicast GM support mobility management easily by
requesting/updating subscriber information to this function. To
track location of mobile node, the multicast GM can deployed with
the location management function for DMM or can be extended flow
entry table in that. Using this function, all multicast subscribers
using the same multicast channel can be managed logically into the
same records wherever they attach to so that it can avoid tunnel
convergence problem. For example, even though two different nodes
subscribing same multicast channel from different access router are
moving to the same access node, the multicast GM can support to use
only one upstream interface to the same multicast source address by
updating its database and signaling with access node. Additionally
the multicast GM function can support optimal multicast routing
which sender and receiver are connected in the DMM domain. According
group database in the multicast GM and location information of
mobile nodes, in case that both sender and subscriber are located in
DMM domain, the multicast AF can forward multicast packets directly
to the access node where receiver is located in.
3.3. Multicast Forwarding Management Function (Multicast FM)
The multicast FM function manages forwarding states that is used to
forward packets from a source to a multicast group. Forwarding
states could be managed together or separately with unicast
forwarding states handled by the DMM FM function. In the former
case, the multicast FM function should be located at the same entity
where the DMM FM function is deployed (e.g. MAG function in
[RFC7028] and [RFC6224]). Basically the multicast FM function
maintains forwarding rules for routing from/to multicast
infrastructure and multicast subscribers, and additionally it can be
used specific forwarding mechanism such as PMIP or GRE tunneling
between multicast FM entities to support mobility.
The multicast FM function can be split into the control and data
plane. The multicast FM control plane (FM-CP) performs multicast
routing mechanism, makes forwarding rules for multicast traffic and
commands to the multicast FM data plane (FM-DP). For communication
between control and data plane, [dmm-fpc-cpdp] can be a method for
configuring forwarding policies. Rule of forwarding multicast
traffic can be considered in various way; a set of forwarding rules
of multicast subscribers or a single rule for each multicast
channel.
4. Considering multicast functions into current approaches
In this section, we consider how multicast functions can be merged
with DMM functional deployment model. In this section, based on DMM
functional deployment model in [sijeon-dmm-deployment-models], we
make use cases which combine or separate multicast functions as we
defined in previous section.
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4.1. Distributed AM, LM, and FM : All-in-One
In this model, all of DMM anchor functions (AF, FM, LM) are combined
into one physical entity and such physical entities are distributed
at the edge of network. This model is presented in [seite-dmm-dma]
and [bernardos-dmm-pmip] To support multicast, the multicast anchor
functions may be deployed together in mobility router. Optionally,
in case of central LM usage, the multicast GM entity also may be
centralized. On the other hand, one or more multicast entity also
may be deployed independently as described in Figure 1. For example,
in case of deploying the multicast AF functions separately,
signaling messages for supporting mobility are required between
All-in-One DMM entity and the multicast AF. In this example, DMM
entity which includes the multicast FM function can perform as
multicast proxy.
+---------------------+
| (LM + GM) |
+---------------------+
^ ^
| |
v v
+--------------+ +------------------+
| AF + LM + FM |(<-->)| M-AF + GM + M-FM |
+--------------+ +------------------+
u m
u m
u m
+------+
| MN |
+------+
Figure 1: Multicast anchor for distributed AM, LM, and FM
4.2. Distributed AF-DP, LM and FM with centralized AF-CP
This model separates AF function into control and data plane. AF-DP
is distributed with LM and FM while AF-CP is centralized in a single
entity. In this model, centralized AF-CP can determine AF-DP based
on policy or network condition. As presented in [RFC7389], specific
routing protocol, such as GTP or GRE, can be used to forward MN's
traffic between AF-DPs.
To support multicast in this model, the multicast AF-CP may be co-
located where DMM AF-CP is placed. The multicast AF-DP may deploy
together with DMM AF-DP or separately. In the latter case, like as
Multimedia Broadcast Multicast Service (MBMS) gateway in
[3GPP TS 36.440], specific AF-DP gateway can be used. Centralized
AF-CP which includes multicast AF-CP can determine the multicast
AF-DP for forwarding multicast traffic of MN. Figure 2 is described
one options for adopting this model.
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+---------------+ +------------------+
| AF-CP (+ LM) |(<-->)| M-AF-CP (+ GM) |
+---------------+ +------------------+
^ ^
(fpc) | | (fpc)
v v
+------------+ +------------+
| AF-DP + | | M-AF-DP + |
| LM + FM | | GM + M-FM |
+------------+ +------------+
u m
u m
+------+
| MN |
+------+
Figure 2: Multicast anchor for distributed AF-DP, LM and
FM with centralized AF-CP
4.3. Distributed AF-DP and FM-DP with centralized AF-CP, LM, and FM-CP
This model considers separation of FM-CP and FM-DP with separation
of AF-CP and AF-DP. In this model, forwarding path between AF-DP can
be provided more flexible. [matsushima-stateless-uplane-vepc] is
one example of this model. To support multicast in this model,
multicast FM-CP, AF-CP and GM may be implemented in centralized
control plane of DMM. In this case, signaling messages between
control and data plane can be used by extending messages which could
be used in normal DMM. For example, [dmm-fpc-cpdp] can be extended
to make rule for multicast traffic by defining group forwarding
rules. Figure 3 is described for this model.
+----------------------+ +--------------------------+
| AF-CP + LM + FM-CP |(<-->)| M-AF-CP + GM + M-FM-CP |
+----------------------+ +--------------------------+
^ ^
(fpc) | | (fpc)
v v
+---------+ +---------+
| AF-DP | | M-AF-DP |
| FM-DP | | M-FM-DP |
+---------+ +---------+
u m
u m
+------+
| MN |
+------+
Figure 3: Multicast anchor for distributed AF-DP and FM-DP
with centralized AF-CP, LM, and FM-CP
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5. Security Considerations
TBD
6. IANA Considerations
TBD
7. References
7.1. Normative References
[RFC2119] S. Bradner, "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
7.2. Informative References
[RFC5213] Gundavelli, S., Leung, K., Devarapalli, V., Chowdhury, K.,
Patil, B., "Proxy Mobile IPv6", RFC 5213, August 2008.
[RFC3810] Vida, R., Costa, L., "Multicast Listener Discovery Version
2 (MLDv2) for IPv6", RFC 3810, June 2004.
[RFC4601] Fenner, B., Handley, M., Holbrook, H., Kouvelas, I.,
"Protocol Independent Multicast - Sparse Mode (PIM-SM):
Protocol Specification (Revised)", RFC 4601, August 2006.
[RFC7429] Liu, D., Zuniga, JC., Seite, P., Chan, H., Bernardos, CJ.,
"Distributed Mobility Management: Current Practices and
Gap Analysis", RFC 7429, January 2015.
[RFC7333] Chan, H., Liu, D., Seite, P., Yokota, H., Korhonen, J.,
"Requirements for Distributed Mobility Management", RFC
7333, August 2014.
[Use Case for Multicast DMM] Figueiredo, S., Jeon, S., Aguiar, R.,
L., "IP Multicast Use Cases and Analysis over Distributed
Mobility Management", draft-sfigueiredo-multimob-use-case-
dmm-03, October 2012 (Expired).
[RFC4605] Fenner, B., He, H., Haberman, B., Sandick, H., "Internet
Group Management Protocol (IGMP) / Multicast Listener
Discovery (MLD)-Based Multicast Forwarding ("IGMP/MLD
Proxying")", RFC 4605, August 2006.
[RFC6224] Schmidt, T., Waehlisch, M., Krishnan, S., "Base Deployment
for Multicast Listener Support in Proxy Mobile IPv6
(PMIPv6) Domains", RFC 6224, April 2011.
[dmm-fpc-cpdp] Liebsch, M., Matsushima, S., Gundavelli, S., Moses,
D., Bertz, L., "Protocol for Forwarding Policy
Configuration (FPC) in DMM", draft-ietf-dmm-fpc-cpdp-03
(work in progress), March 2016.
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[sijeon-dmm-deployment-models] Jeon, S., Kim, Y., "Deployment Models
for Distributed Mobility Management", draft-sijeon-dmm-
deployment-models-02 (work in progress), March 2016.
[seite-dmm-dma] Seite, P., Bertin, P., and J. Lee, "Distributed
Mobility Anchoring" (Expired), draft-seite-dmm-dma-07,
February 2014.
[bernardos-dmm-pmip] Bernardos, C., Oliva, A., and F. Giust, "A
PMIPv6-based solution for Distributed Mobility
Management", draft-bernardos-dmm-pmip-06 (work in
progress), March 2016.
[RFC7389] Wakikawa, R., Pazhyannur, R., Gundavelli, S., and C.
Perkins, "Separation of Control and User Plane for Proxy
Mobile IPv6", RFC 7389, October 2014.
[3GPP TS 36.440] ETSI TS 36.440 v12.0.0, "LTE; Evolved Universal
Terrestrial Radio Access Network (E-UTRAN); General
aspects and principles for interfaces supporting
Multimedia Broadcast Multicast Service (MBMS) within
E-UTRAN (3GPP TS 36.440 version 12.0.0 Release 12)",
September 2014.
[matsushima-stateless-uplane-vepc] Matsushima, S. and R. Wakikawa,
"Stateless user-plane architecture for virtualized EPC
(vEPC)", draft-matsushima-stateless-uplane-vepc-06 (work
in progress), March 2016.
8. Acknowledgments
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Authors' Addresses
Kyoungjae Sun
Soongsil University
369, SSnagdo-ro, Dongjak-gu
Seoul, Korea
Email: gomjae@dcn.ssu.ac.kr
Younghan Kim
Soongsil University
369, SSnagdo-ro, Dongjak-gu
Seoul, Korea
Email: younghak@ssu.ac.kr
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