Multicast Routing Optimization by PIM-SM with PMIPv6
draft-asaeda-multimob-pmip6-extension-09
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draft-asaeda-multimob-pmip6-extension-09
MULTIMOB Group H. Asaeda
Internet-Draft Keio University
Intended status: Standards Track P. Seite
Expires: September 27, 2012 France Telecom
March 26, 2012
Multicast Routing Optimization by PIM-SM with PMIPv6
draft-asaeda-multimob-pmip6-extension-09
Abstract
This document describes IP multicast routing optimization using
PIM-SM in Proxy Mobile IPv6 (PMIPv6) environment. The Mobile Access
Gateway (MAG) and the Local Mobility Anchor (LMA) are the mobility
entities defined in the PMIPv6 protocol and act as PIM-SM routers.
The proposed protocol optimization addresses the tunnel convergence
problem and provides seamless handover.
Status of this Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
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This Internet-Draft will expire on September 27, 2012.
Copyright Notice
Copyright (c) 2012 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
carefully, as they describe your rights and restrictions with respect
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 . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Conventions and Terminology . . . . . . . . . . . . . . . . . 4
3. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
3.1. Multicast Communication in PMIPv6 . . . . . . . . . . . . 4
3.2. Protocol Sequence for Multicast Channel Subscription . . . 6
4. Multicast Tunnel (M-Tunnel) . . . . . . . . . . . . . . . . . 7
4.1. Packet Encapsulation . . . . . . . . . . . . . . . . . . . 7
4.2. Multiple M-Tunnels and ECMP Routing . . . . . . . . . . . 8
5. Local Mobility Anchor Operation . . . . . . . . . . . . . . . 9
6. Mobile Access Gateway Operation . . . . . . . . . . . . . . . 10
7. Mobile Node Operation . . . . . . . . . . . . . . . . . . . . 11
8. Smooth Handover . . . . . . . . . . . . . . . . . . . . . . . 11
8.1. Handover with Policy Profile . . . . . . . . . . . . . . . 11
8.2. Handover with Extended Proxy Binding Update and
Acknowledgement . . . . . . . . . . . . . . . . . . . . . 14
9. Message Format Extension . . . . . . . . . . . . . . . . . . . 16
9.1. Proxy Binding Update with Multicast Extension . . . . . . 16
9.2. Proxy Binding Acknowledgement Message with Multicast
Extension . . . . . . . . . . . . . . . . . . . . . . . . 19
10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 19
11. Security Considerations . . . . . . . . . . . . . . . . . . . 21
12. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 21
13. References . . . . . . . . . . . . . . . . . . . . . . . . . . 21
13.1. Normative References . . . . . . . . . . . . . . . . . . . 21
13.2. Informative References . . . . . . . . . . . . . . . . . . 22
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 22
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1. Introduction
Proxy Mobile IPv6 (PMIPv6) [1] enables network-based mobility for
IPv6 mobile nodes (MNs) that do not implement any mobility protocols.
The Local Mobility Anchor (LMA) is the topological anchor point to
manages the mobile node's binding state. The Mobile Access Gateway
(MAG) is an access router or gateway that manages the mobility-
related signaling for an MN. An MN is attached to the Proxy Mobile
IPv6 Domain (PMIPv6-Domain) that includes LMA and MAG(s), and is able
to receive data coming from outside of the PMIPv6-Domain through LMA
and MAG.
Network-based mobility support for unicast is addressed in [1], while
multicast support in PMIPv6 is not discussed in it. Since LMA and
MAG set up a bi-directional IPv6-in-IPv6 tunnel for each mobile node
and forwards all mobile node's traffic according to [1], it highly
wastes network resources when a large number of mobile nodes join/
subscribe the same multicast sessions/channels, because independent
data copies of the same multicast packet are delivered to the
subscriber nodes in a unicast manner through MAG.
The base solution described in [11] provides options for deploying
multicast listener functions in PMIPv6-Domains without modifying
mobility and multicast protocol standards. However, in this
specification, MAG MUST act as an MLD proxy [2] and hence MUST
dedicate a tunnel link between LMA and MAG to an upstream interface
for all multicast traffic. This limitation does not allow to use
PIM-SM native routing on MAG, and hence does not solve the tunnel
convergence problem; MAG receives the same data from multiple LMAs
when MAG attaches to them for mobile nodes and has subscribed the
same multicast channel to them. It does not enable direct routing
and does not optimize source mobility.
This document describes IP multicast routing optimization using
PIM-SM in Proxy Mobile IPv6 (PMIPv6) environment. The Mobile Access
Gateway (MAG) and the Local Mobility Anchor (LMA) are the mobility
entities defined in the PMIPv6 protocol and act as PIM-SM routers.
The proposed protocol optimization assumes that both LMA and MAG
enable the Protocol-Independent Multicast - Sparse Mode (PIM-SM)
multicast routing protocol [3]. The proposed optimization uses a
dedicated GRE [4] tunnel for multicast, called M-Tunnel, between LMA
and MAG. The proposed protocol optimization addresses the tunnel
convergence problem and provides seamless handover. It can cooperate
with local routing and direct routing to deliver IP multicast packets
for mobile nodes and source mobility. In this document, because
multicast listener mobility is mainly focused on, the detail
specification of source mobility is not described.
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This document does not require to change unicast communication
methods or protocols defined in [1], and therefore both unicast and
multicast communications for mobile nodes in PMIPv6-Domain are
enabled if this extension is implemented.
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 [5].
The following terms used in this document are to be interpreted as
defined in the Proxy Mobile IPv6 specification [1]; Mobile Access
Gateway (MAG), Local Mobility Anchor (LMA), Mobile Node (MN), Proxy
Mobile IPv6 Domain (PMIPv6-Domain), LMA Address (LMAA), Proxy Care-of
Address (Proxy-CoA), Mobile Node's Home Network Prefix (MN-HNP),
Mobile Node Identifier (MN-Identifier), Proxy Binding Update (PBU),
and Proxy Binding Acknowledgement (PBA).
3. Overview
3.1. Multicast Communication in PMIPv6
Required components to enable IP multicast are multicast routing
protocols and host-and-router communication protocols. This document
assumes PIM-SM [3] as the multicast routing protocol and Multicast
Listener Discovery (MLD) as the host-and-router communication
protocol. This document allows mobile nodes to participate in Any-
Source Multicast (ASM) and Source-Specific Multicast (SSM) [6].
However, in order to explicitly participate in SSM, mobile nodes MUST
support either MLDv2 [7] or Lightweight-MLDv2 (LW-MLDv2) [8].
The architecture of a Proxy Mobile IPv6 domain is shown in Figure 1.
LMA and MAG are the core functional entities in PMIPv6-Domain. The
entire PMIPv6-Domain appears as a single link from the perspective of
each mobile node.
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+---------+
| Content |
| Source |
+---------+
|
*** *** *** *** ***
* ** ** ** ** *
* *
* Fixed Internet *
* *
* ** ** ** ** *
*** *** *** *** ***
/ \
+----+ +----+
|LMA1| |LMA2|
+----+ +----+
LMAA1 -> | | <-- LMAA2
| |
\\ //\\
\\ // \\
\\ // \\
\\ // \\
\\ // \\
\\ // \\
Proxy-CoA1--> | | <-- Proxy-CoA2
+----+ +----+
|MAG1|---{MN2} |MAG2|
+----+ | +----+
| | |
MN-HNP1 --> | MN-HNP2 | <-- MN-HNP3, MN-HNP4
{MN1} {MN3}
Figure 1: Proxy Mobile IPv6 Domain
When a mobile node wants to subscribe/unsubscribe a multicast
channel, it sends MLD Report messages specifying sender and multicast
addresses to the access link. The attached MAG detects this
membership information and sends the PIM Join/Prune message to the
corresponding LMA over the LMA-MAG bi-directional IPv6-in-IPv6 tunnel
when the LMA is selected as the previous-hop router for the multicast
channel, or sends the PIM Join/Prune message to the adjacent upstream
multicast router for the multicast channel. When the LMA or the
adjacent router receives the PIM Join/Prune message, it coordinates
the corresponding multicast routing tree if necessary and starts
forwarding the data.
When the MAG detects mobile node's handover, it can proceed the
seamless handover procedures. Since both PMIPv6 and multicast
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protocols (i.e., MLD and PIM-SM) do not have functions for multicast
context transfer in their original protocol specifications, the
external functions or protocols should be used for handover. One of
the possibile ways is the use of "mobile node's Policy Profile", as
it could include "multicast channel information", which expresses
mobile node's subscribing multicast channel list, as well as the
mandatory fields of the Policy Profile specified in [1]. Mobile
node's Policy Profile is provided by "policy store" whose definition
is the same as of [1].
3.2. Protocol Sequence for Multicast Channel Subscription
A mobile node sends unsolicited MLD Report messages including source
and multicast addresses when it subscribes a multicast channel.
Although MLDv2 specification [7] permits to use the unspecified
address (::) for a host whose interface has not acquired a valid
link-local address yet, MAG SHOULD send MLDv2 Report messages with a
valid IPv6 link-local source address as defined in [12]. As well,
MLDv2 Report messages MAY be sent with an IP destination address of
FF02:0:0:0:0:0:0:16, to which all MLDv2-capable multicast routers
listen, but the IP unicast address of the attached MAG SHALL be used
for the destination of MLDv2 Report messages.
When the MAG operating as a PIM-SM router receives MLD Report
messages from attached mobile nodes, it joins the multicast delivery
tree by sending PIM Join messages to its neighboring routers
(Figure 2). When the upstream router for the requested channel is
LMA, the MAG sends the corresponding PIM Join messages over the
regular LMA-MAG bi-directional tunnel, if the MAG has no multicast
state for the requested channel. When the upstream router for the
requested channel is an adjacent router that is not the LMA, the MAG
sends the corresponding PIM Join messages to the adjacent upstream
router natively, if the MAG has no multicast state for the requested
channel. The LMA or the adjacent upstream router then joins the
multicast delivery tree and forwards the packets to the downstream
MAG.
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MN1 MN2 MAG LMA
| | | |
|------MLD Report--------->| |
| (S1,G1) join | PIM (S1,G1) Join |
| | |===== M-Tunnel ===>|
| | | |---> PIM (S1,G1) Join
| | | |
| |--MLD Report-->| |
| | (S2,G2) join | |
| | |---> PIM (S2,G2) Join
| | | |
| |--MLD Report-->| |
| | (S1,G1) join | |
| | | |
Figure 2: MLD Report Messages Transmission
The MAG selects only one upstream link for a multicast channel by the
Reverse Path Forwarding (RPF) algorithm even if the MAG has
established multiple bi-directional tunnels for unicast transmission
to different LMAs. This does not cause the tunnel convergence
problem, because Multicast Routing Information Base (MRIB) used by
PIM-SM selects only one incoming interface for each multicast channel
and hence duplicate packets are not forwarded to the MAG.
4. Multicast Tunnel (M-Tunnel)
4.1. Packet Encapsulation
M-Tunnel is a bi-directional GRE tunnel [4] dedicated for PIM
messages and IP multicast data transmissions between LMA and MAG.
M-Tunnel is established between PIM-SM capable LMA and MAG. It can
be established in a bootstrap phase of MAG (without detecting a
multicast channel subscription request from a mobile node) and kept
while the MAG enables PIM routing functions to forward multicast
packets. M-Tunnel is not set up per mobile node basis, but per MAG
basis; it is shared with mobile nodes attached to the MAG as seen in
Figure 3.
MC1
\
\-->
MC2---->LMA===MC1,MC2 for MNs====>MAG
MC: Multicast packets, ==>: M-Tunnel
Figure 3: Multicast packet forwarding through M-Tunnel
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In order for the PIM routing protocol to use M-Tunnels for multicast
forwarding, an M-Tunnel interface must be recognized as the upstream
multicast interface for MAG. It is done by the configuration of
static multicast routes, such as "ip mroute 0.0.0.0 0.0.0.0 gre0".
By such configuration, MAG enabling the PIM routing function inserts
the route paths using M-Tunnel into its MRIB and selects a single
M-Tunnel as the RPF interface and PIM messages, and IP multicast data
are forwarded over the M-Tunnel. If operators want to select other
interface, e.g. a physical interface, as the upstream multicast
interface for some specific source prefixes, e.g. sources inside the
PMIPv6-Domain, they can additionally configure the specific multicast
routes with longer prefixes. Then the MAG selects as the appropriate
upstream router according to the MRIB entry. Note that the case
having multiple M-Tunnels configured on MAG is described in
Section 4.2.
The format of the tunneled multicast packet forwarded from LMA is
shown below. "S" and "G" are the same notation used for (S,G)
multicast channel.
IPv6 header (src= LMAA, dst= Proxy-CoA) /* Outer Header */
GRE header /* Encapsulation Header */
IPv6 header (src= S, dst= G) /* Inner Header */
Upper layer protocols /* Packet Content */
Figure 4: Multicast packet format tunneled from LMA to MAG
When a PIM message is sent from MAG to LMA, the src and dst addresses
of the outer tunnel header will be replaced to Proxy-CoA and LMAA,
respectively. To convey a PIM message, the src address of the inner
packet header is changed to either LMA's or MAG's link-local address.
The dst address of the packet header is assigned based on the PIM's
condition (see [3]).
In order to establish M-Tunnel, LMA and MAG need to negotiate GRE
encapsulation and GRE keys for M-Tunnel. The GRE Key option to be
used for the negotiation of GRE tunnel encapsulation mode and
exchange of the uplink and downlink GRE keys is defined in [9]. It
is also possible to use the static fixed GRE keys for M-Tunnel.
4.2. Multiple M-Tunnels and ECMP Routing
There can be multiple LMAs in a PMIPv6-Domain each serving a
different group of mobile nodes. In that case, a MAG will connect to
multiple LMAs with different M-Tunnels having different GRE keys.
For example, in Figure 5, MAG1 establishes two M-Tunnels with LMA1
and LMA2, and MAG2 establishes one M-Tunnel with LMA2.
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A MAG that has multiple M-Tunnels, such as MAG1 in Figure 5, must
decide a single upstream M-Tunnel interface for an RP or a source
address or prefix. There are two ways to decide a single upstream
M-Tunnel for a MAG. One is only with static MRIB configuration by
operation. For example, operator can configure one of the M-Tunnel
interfaces as the RPF interface for specific source adddress(es) or
prefix(es) to insert into the MRIB for the MAG.
The other way to select a single upstream M-Tunnel interface is with
PIM ECMP [13]. A MAG enabling PIM routing functions selects a path
in the ECMP based on its own implementation specific choice, which
may refer to the description in [13]. The PIM ECMP function chooses
the PIM neighbor with the highest IP address, or picks the PIM
neighbor with the best hash value over the destination and source
addresses. When operators decide to use PIM ECMP to select a single
upstream M-Tunnel from multiple M-Tunnels established between MAG and
LMAs, both MAG and LMAs MUST enable PIM ECMP for their possiblly
selecteded M-Tunnels.
+----+ +----+
|LMA1| |LMA2|
+----+ +----+
|| || ||
|| || ||
\\ M-Tunnel // \\
\\ | // \\
\\ +-> // \\ <-- M-Tunnel
M-Tunnel ---> \\ // \\
(encapsulating \\ // \\
with GRE header) \\ // \\
|| || ||
+----+ +----+
|MAG1|---{MN2} |MAG2|
+----+ +----+
| |
| |
{MN1} {MN3}
Figure 5: M-Tunnels established between LMA and MAG
5. Local Mobility Anchor Operation
The LMA is responsible for maintaining the mobile node's reachability
state and is the topological anchor point for the mobile node's home
network prefix(es). This document assumes that the LMA is capable of
forwarding multicast packets to the MAG by enabling the Protocol-
Independent Multicast - Sparse Mode (PIM-SM) multicast routing
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protocol [3]. The LMA acting as a PIM-SM multicast router may serve
MAGs as downstream routers for some multicast channels when a mobile
node is a multicast data receiver (or as upstream routers when a
mobile node is a multicast data sender). The downstream (or
upstream) MAG is connected to the LMA through the LMA-MAG bi-
directional tunnel for multicast communication.
When the LMA sets up the multicast state and joins the group as the
MAG's upstream router, the multicast packets are tunneled to the MAG
that requested to receive the corresponding multicast session. The
MAG then forwards the packets to the mobile node according to the
multicast listener state maintained in the MAG. [1] supports only
point-to-point access link types for MAG and mobile node connection;
hence a mobile node and the MAG are the only two nodes on an access
link, where the link is assumed to be multicast capable.
6. Mobile Access Gateway Operation
The MAG is the entity that performs the mobility management on behalf
of a mobile node. This document assumes that MAG is capable of
forwarding multicast packets to the corresponding mobile nodes
attached to MAG by enabling the PIM-SM multicast routing protocol.
In addition, MAG must maintain multicast membership status for the
attached mobile nodes at the edge and forwards the multicast data to
the member mobile nodes. This condition requires MAG to support
MLDv2 [7] or LW-MLDv2 [8], as well.
When mobile nodes subscribe multicast channel(s), they send MLD
Report messages with their link-local address to the MAG, and the MAG
sends the corresponding PIM Join messages to the upstream router if
the MAG has no multicast state for the requested channel(s). The
upstream router is selected by the Reverse Path Forwarding (RPF)
lookup algorithm, and that is either LMA or an adjacent multicast
router attached to the same link. If the LMA is the upstream router
for the channel(s) for the MAG, the MAG encapsulates PIM Join
messages using the LMA-MAG bi-directional tunnel.
The MAG also sends MLD Query messages to attached mobile nodes to
maintain up-to-date membership states. Since the MAG may deal with a
large number of the downstream mobile nodes, the MLD protocol
scalability should be taken into account as described in [12].
Therefore it is RECOMMENDED that the explicit tracking function [14]
is enabled on MAG.
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7. Mobile Node Operation
Mobile nodes attached to MAG can behave as regular receiver hosts. A
mobile node sends MLD messages to MAG when it wants to subscribe and
unsubscribe IP multicast channels.
In order to subscribe/unsubscribe multicast channel(s) by unsolicited
report messages and inform current membersip state by solicited
report messages, mobile nodes MUST support either MLDv1 [7], MLDv2
[7], or LW-MLDv2 [8], and SHOULD support MLDv2 or LW-MLDv2.
8. Smooth Handover
MAG is responsible for detecting the mobile node's movements to and
from the access link and for initiating binding registrations to the
mobile node's LMA. MAG tracks the mobile node's movements to and
from the access link and for signaling the mobile node's LMA. In
PMIPv6, it SHOULD NOT require for mobile nodes to initiate to re-
subscribe multicast channels, and MAG SHOULD keep multicast channel
subscription status for mobile nodes even if they move to a different
MAG (i.e., n-MAG) in PMIPv6-Domain.
MAG needs to join the multicast delivery tree when an attached mobile
node subscribes a multicast channel. When the mobile node changes
the network, it should seamlessly receive multicast data from the new
MAG according to the multicast channel information stored in the
"MN's Policy Profile" or by the "multicast context transfer
mechanism". Whether the MN's Policy Profile or the multicast context
transfer mechanism mobile operators use depend on their policy or
implementation.
8.1. Handover with Policy Profile
When the multicast channel information subscribed by mobile nodes is
maintained in "MN's Policy Profile" stored in a policy store [1], MAG
can use the channel information to provide seamless handover. The
procedures are described as follows and illustrated in Figure 6;
1. Figure 6 shows the examples that a mobile node has received
multicast data from an upstream multicast router via p-MAG (*1)
and from LMA via p-MAG (*2).
2. Whenever the mobile node moves a new network and attaches to
n-MAG, the n-MAG obtains the MN-Identifier (MN-ID) and learns
multicast channel information described in Mobile Node's Policy
Profile associated to this MN-Identifier. Describing the method
how the n-MAG identifies the p-MAG is out of scope of this
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document, while using the same mechanism described in [15] would
be one of the possible methods.
3. If there are multicast channels the mobile node has subscribed
but the n-MAG has not yet subscribed, n-MAG joins the
corresponding multicast channels by sending the PIM Join message
to its upstream router. If the upstream router is LMA, the PIM
messages are encapsulated and transmitted over the LMA-MAG bi-
directional tunnel (*4); otherwise the PIM messages are sent
natively to the adjacent upstream router (*3).
4. The multicast data is forwarded from LMA through the bi-
directional tunnel between the LMA and n-MAG (*4) or from the
adjacent upstream router (*3).
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MN p-MAG LMA n-MAG
| | | |
|--MLD Report->| | |
| |---> PIM Join (*1) |
| | PIM Join (*2) | |
| |== Bi-dir tunnel =>| |
| | |---> PIM Join (*2)
| | | |
|<--Multicast--| | |
| data (*1) | | |
| |Multicast data (*2)| |
|<-------------|<= Bi-dir tunnel ==| |
| | | |
Detach | | |
| | | |
Attach | | |
| | | MN attachment event
| | | (Acquire MN-ID and Profile)
|-------------------------RS-------------------------->|
| | | |
| | |<-------PBU--------|
| | | |
| | |--------PBA------->|
| | | |---> PIM Join (*3)
| | | PIM Join (*4) |
| | |<= Bi-dir tunnel ==|
| | | |
|<------------------------RA---------------------------|
| | | |
| | Multicast data (*3) |
|<-----------------------------------------------------|
| | |Multicast data (*4)|
| | |== Bi-dir tunnel =>|
|<-----------------------------------------------------|
| | | |
Figure 6: Handover with MN's Policy Profile
After MN attaches to n-MAG, the multicast data will be delivered to
the MN immediately. MN's multicast membership state is maintained
with MLD Query and Report messages exchanged by MN and n-MAG. If
p-MAG thinks that the moving mobile node is the last member of
multicast channel(s) (according to the membership record maintained
by the explicit tracking function [14]), p-MAG confirms it by sending
MLD query. After the confirmation, p-MAG leaves the channel(s) by
sending the PIM Prune message to its upstream router.
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8.2. Handover with Extended Proxy Binding Update and Acknowledgement
This document provides the multicast extension for the PBU message,
which is named "Proxy Binding Update with multicast extension
(PBU-M)" (detailed in Section 9.1), and the PBA message, which is
named "Proxy Binding Acknowledge with multicast extension (PBA-M)"
(detailed in Section 9.2), to inform n-MAG to subscribe multicast
channel(s) for moving mobile nodes.
1. Figure 7 shows the examples that a mobile node has received
multicast data from an upstream multicast router via p-MAG (*1)
and from LMA via p-MAG (*2).
2. Whenever the mobile node moves a new network, the p-MAG sends
de-registration PBU-M message having the lifetime value of zero
(see Section 9.1) to the LMA. The LMA then transmits the PBA
message and keeps the multicast channel information included in
that message.
3. When the mobile node attaches to n-MAG, the n-MAG obtains the
MN-Identifier (MN-ID) and transmits the regular PBU message.
4. Whenever the LMA receives the PBU message, it transmits the
PBA-M message including multicast channel information that the
mobile node has joined.
5. If there are multicast channels in the channel information the
mobile node has subscribed but the n-MAG has not yet subscribed,
the n-MAG joins the corresponding multicast channels by sending
the PIM Join message to its upstream router.
6. Follow the procedures of step 3 and 4 in Section 8.1.
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MN p-MAG LMA n-MAG
| | | |
| | | |
|--MLD Report->| | |
| |---> PIM Join (*1) |
| | PIM Join (*2) | |
| |== Bi-dir tunnel =>| |
| | |---> PIM Join (*2)
| | | |
|<--Multicast--| | |
| data (*1) | | |
| |Multicast data (*2)| |
|<-------------|<= Bi-dir tunnel ==| |
| | | |
Detach | | |
| MN detachment event | |
| | | |
| |----DeReg PBU-M--->| |
| | | |
| | Accept PBU |
| |<-------PBA--------| |
Attach | | |
| | | MN attachment event
| | | (Acquire MN-ID)
|-------------------------RS-------------------------->|
| | | |
| | |<-------PBU--------|
| | | |
| | |-------PBA-M------>|
| | (Acquire multicast channel
| | information for MN-ID)
| | | |
| | | |---> PIM Join (*3)
| | | PIM Join (*4) |
| | |<= Bi-dir tunnel ==|
| | | |
|<------------------------RA---------------------------|
| | | |
| | Multicast data (*3) |
|<-----------------------------------------------------|
| | |Multicast data (*4)|
| | |== Bi-dir tunnel =>|
|<-----------------------------------------------------|
| | | |
Figure 7: Handover with PBU-M and PBA-M
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9. Message Format Extension
9.1. Proxy Binding Update with Multicast Extension
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sequence # |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|A|H|L|K|M|R|P|C| Reserved | Lifetime |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
. .
. Mobility options .
. .
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 8: Proxy Binding Update Message with Multicast Extension
A Binding Update message that is sent by MAG to LMA is referred to as
the "Proxy Binding Update" message. A new flag (C) is included in
the Proxy Binding Update message with Multicast extension (PBU-M).
The rest of the Binding Update message format remains the same as
defined in [16] and with the additional (R), (M), and (P) flags, as
specified in [17], [18], and [1], respectively.
Multicast Channel Subscription Flag
A new flag (C) is included in the Binding Update message to
indicate to LMA that the Binding Update message is a multicast
channel subscription.
The PBU-M message is transfered for binding de-registration from
p-MAG to LMA as apecified in Section 8.2, the Lifetime value MUST be
zero.
When (C) flag is specified in PBU-M message, the Mobility options
field includes "multicast channel information", which is the same
information of MLDv2 Report message. The format of the Mobility
options field uses the TLV format defined in [16] where the field
contain Multicast Address Record with the same definitions in [7].
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0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type = TBD | Length |Nr of Mcast Address Records (M)|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
. .
. Multicast Address Record [1] .
. .
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
. .
. Multicast Address Record [2] .
. .
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| . |
. . .
| . |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
. .
. Multicast Address Record [M] .
. .
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 9: Multicast channel information
Each Multicast Address Record has the following internal format,
where the Record Type MUST be always "1" (i.e., MODE_IS_INCLUDE).
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Record Type = 1| Aux Data Len | Number of Sources (N) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
* *
| |
* Multicast Address *
| |
* *
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
* *
| |
* Source Address [1] *
| |
* *
| |
+- -+
| |
* *
| |
* Source Address [2] *
| |
* *
| |
+- -+
. . .
. . .
. . .
+- -+
| |
* *
| |
* Source Address [N] *
| |
* *
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
. .
. Auxiliary Data .
. .
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 10: Multicast Address Record format
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9.2. Proxy Binding Acknowledgement Message with Multicast Extension
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Status |K|R|P|C|Reserve|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sequence # | Lifetime |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
. .
. Mobility options .
. .
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 11: PBA with Multicast Extension
A "Proxy Binding Acknowledgement" message is sent from LMA to MAG in
response to a Proxy Binding Update message. A new flag (C) is
included in the Proxy Binding Acknowledgement message with Multicast
extension (PBA-M). The rest of the Binding Acknowledgement message
format remains the same as defined in [16] and with the additional
(R) flag, as specified in [17] and [1], respectively.
Multicast Channel Subscription Flag
A new flag (C) is included in the Binding Acknowledgement message
to indicate to MAG that the Binding Acknowledgement message is a
multicast channel subscription.
When (C) flag is specified in PBA-M message, the mobility options
field includes "multicast channel information", which is the same
information of MLDv2 Report message [7] as described in Section 9.1.
10. IANA Considerations
This document creates a new registry for the flags in the Binding
Update message called the "Binding Update Flags".
The following flags are reserved:
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(A) 0x8000 [RFC3775]
(H) 0x4000 [RFC3775]
(L) 0x2000 [RFC3775]
(K) 0x1000 [RFC3775]
(M) 0x0800 [RFC4140]
(R) 0x0400 [RFC3963]
(P) 0x0200 [RFC5213]
This document reserves a new flag (C) for "Proxy Binding Update with
Multicast Extension" as described in Section 9.1 as follows:
(C) 0x0100
The rest of the values in the 16-bit field are reserved. New values
can be assigned by Standards Action or IESG approval.
This document also creates a new registry for the flags in the
Binding Acknowledgment message called the "Binding Acknowledgment
Flags".
The following flags are reserved:
(K) 0x80 [RFC3775]
(R) 0x40 [RFC3963]
(P) 0x20 [RFC5213]
This document reserves a new flag (C) for "Proxy Binding
Acknowledgement with Multicast Extension" as described in Section 9.2
as follows:
(C) 0x010
The rest of the values in the 8-bit field are reserved. New values
can be assigned by Standards Action or IESG approval.
The IANA should also allocate the value of the type field of
"multicast channel information" described in Section 9.1 for the
Mobility options field upon publication of the first RFC.
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11. Security Considerations
TBD.
12. Acknowledgements
Many of the specifications described in this document are discussed
and provided by the multimob mailing-list.
13. References
13.1. Normative References
[1] Gundavelli, S, Ed., Leung, K., Devarapalli, V., Chowdhury, K.,
and B. Patil, "Proxy Mobile IPv6", RFC 5213, August 2008.
[2] 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, August 2006.
[3] Fenner, B., Handley, M., Holbrook, H., and I. Kouvelas,
"Protocol Independent Multicast - Sparse Mode (PIM-SM):
Protocol Specification (Revised)", RFC 4601, August 2006.
[4] Farinacci, D., Li, T., Hanks, S., Meyer, D., and P. Traina,
"Generic Routing Encapsulation (GRE)", RFC 2784, March 2000.
[5] Bradner, S., "Key words for use in RFCs to indicate requirement
levels", RFC 2119, March 1997.
[6] Holbrook, H. and B. Cain, "Source-Specific Multicast for IP",
RFC 4607, August 2006.
[7] Vida, R. and L. Costa, "Multicast Listener Discovery Version 2
(MLDv2) for IPv6", RFC 3810, June 2004.
[8] Liu, H., Cao, W., and H. Asaeda, "Lightweight Internet Group
Management Protocol Version 3 (IGMPv3) and Multicast Listener
Discovery Version 2 (MLDv2) Protocols", RFC 5790,
February 2010.
[9] Muhanna, A., Khalil, M., Gundavelli, S., and K. Leung, "Generic
Routing Encapsulation (GRE) Key Option for Proxy Mobile IPv6",
RFC 5845, June 2010.
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[10] Deering, S., Fenner, W., and B. Haberman, "Multicast Listener
Discovery (MLD) for IPv6", RFC 2710, October 1999.
13.2. Informative References
[11] Schmidt, T., Waehlisch, M., and S. Krishnan, "Base Deployment
for Multicast Listener Support in Proxy Mobile IPv6 (PMIPv6)
Domains", RFC 6224, April 2011.
[12] Asaeda, H., Liu, H., and Q. Wu, "Tuning the Behavior of IGMP
and MLD for Routers in Mobile and Wireless Networks",
draft-ietf-multimob-igmp-mld-tuning-04.txt (work in progress),
March 2012.
[13] Thaler, D. and C. Hopps, "Multipath Issues in Unicast and
Multicast Next-Hop Selection", RFC 2991, November 2000.
[14] Asaeda, H. and N. Leymann, "IGMP/MLD-Based Explicit Membership
Tracking Function for Multicast Routers",
draft-ietf-pim-explicit-tracking-00.txt (work in progress),
October 2011.
[15] Yokota, H., Chowdhury, K., Koodli, R., Patil, B., and F. Xia,
"Fast Handovers for Proxy Mobile IPv6", RFC 5949,
September 2010.
[16] Johnson, D., Perkins, C., and J. Arkko, "Mobility Support in
IPv6", RFC 3775, June 2004.
[17] Devarapalli, V., Wakikawa, R., Petrescu, A., and P. Thubert,
"Network Mobility (NEMO) Basic Support Protocol", RFC 3963,
January 2005.
[18] Soliman, H., Castelluccia, C., El Malki, K., and L. Bellier,
"Hierarchical Mobile IPv6 Mobility Management (HMIPv6)",
RFC 4140, August 2005.
[19] Loughney, Ed., J., Nakhjiri, M., Perkins, C., and R. Koodli,
"Context Transfer Protocol (CXTP)", RFC 4067, July 2005.
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Authors' Addresses
Hitoshi Asaeda
Keio University
Graduate School of Media and Governance
5322 Endo
Fujisawa, Kanagawa 252-0882
Japan
Email: asaeda@wide.ad.jp
URI: http://www.sfc.wide.ad.jp/~asaeda/
Pierrick Seite
France Telecom
4, rue du Clos Courtel
BP 91226, Cesson-Sevigne 35512
France
Email: pierrick.seite@orange-ftgroup.com
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