wdiff draft-ietf-ssm-overview-02.txt draft-ietf-ssm-overview-03.txt

INTERNET-DRAFT Supratik Bhattacharyya
Expires 04 June September 2002 Christophe Diot
Sprint ATL
Leonard Giuliano
Juniper Networks
Rob Rockell
Sprint E|Solutions
John Meylor
Cisco Systems
David Meyer
Sprint E|Solutions
Greg Shepherd
Juniper Networks
Brian Haberman
No Affiliation
4 December 2001
04 March 2002

An Overview of Source-Specific Multicast(SSM) Deployment
<draft-ietf-ssm-overview-02.txt> Multicast (SSM)
<draft-ietf-ssm-overview-03.txt>

Status of this Memo

This document is an Internet-Draft and is in full conformance with
all provisions of Section 10 of RFC2026.

Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF), its areas, and its working groups. Note that
other groups may also distribute working documents as Internet-
Drafts.

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."

The list of current Internet-Drafts can be accessed at
http://www.ietf.org/ietf/1id-abstracts.txt

The list of Internet-Draft Shadow Directories can be accessed at
http://www.ietf.org/shadow.html.

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 [RFC 2119].

Abstract

This document provides an overview of the Source-Specific Multicast
(SSM) service and its deployment using the PIM-SM and IGMP/MLD
protocols. The network layer service provided by SSM is a "channel",
identified by an SSM destination IP address (G) and a source IP
address S. The An IPv4 address range 232/8 has been reserved by IANA fo for use
by the SSM service. An SSM destination address range already exists
for IPv6. A source S transmits IP datagrams to an SSM destination
address G. A receiver can receive these datagrams by subscribing to
the channel (S,G). Channel subscription is supported by version 3 of
the IGMP protocol for IPv4 and version2 of the MLD protocol for IPv6.
The interdomain tree for forwarding IP multicast datagrams is rooted
at the source S. Although a number of protocols
exists for constructing source-rooted forwarding trees, this document
discusses one of S, and is constructed using the most widely implemented one - PIM Sparse Mode
[PIM-SM-NEW]. [PIM-
SM-NEW] protocol.

This document is not intended as to be a starting point standard for Source-Specific
Multicast (SSM). Instead, its goal is to serve as an introduction to
SSM and and its benefits for anyone interested in deploying SSM
services. It provides an architectural overview of SSM and describes and how it solves a
number of problems faced in the deployment of inter-
domain inter-domain multicast.
It outlines changes to protocols and applications both at end-hosts
and routers for supporting SSM, with pointers to more detailed
documents where appropriate. Issues of interoperability with the
multicast service model defined by RFC 1112 are also discussed.

1. Terminology

This section defines some terms that are used in the rest of this
document :

Any-Source Multicast (ASM) : This is the IP multicast service model
defined in RFC 1112 [RFC1112]. An IP datagram is transmitted to a
"host group", a set of zero or more end-hosts identified by a single
IP destination address (224.0.0.0 through 239.255.255.255 for IPv4).
This model supports one-to-many and and many-to-many multicast groups.
End-hosts may join and leave the group any time, and there is no
restriction on their location or number. Moreover, this model supports
multicast groups with arbitrarily many senders - any end-host may
transmit to a host group, even if it is not a member of that group.

Source-Specific Multicast (SSM) : This is the multicast service model
defined in [SSM-ARCH]. An IP datagram is transmitted by a source S to
an SSM destination address G, and receivers can receive this datagram
by subscribing to channel (S,G). SSM provides host applications with a
"channel" abstraction, in which each channel has exactly one source
and any number of receivers. SSM is derived from earlier work in
EXPRESS [EXPRESS]
and supports one-to-many multicast.The [EXPRESS].The address range 232/8 has been assigned by IANA
[IANA-ALLOC] for SSM service in IPv4. For IPv6, the range FF3x::/96 is
defined for SSM services [SSM-IPv6].

Source-Filtered Multicast (SFM) : This is a variant of the multicast ASM service model defined in RFC 1112. A source transmits IP datagrams to
a host group address in
model, and uses the same address range of 224.0.0.0 to 239.255.255.255.
However, each as ASM
(224.0.0.0-239.255.255.255). It extends the ASM service model as
follows. Each "upper layer protocol module" can now request data sent
to a host group G by only a specific set of sources, or can request
data sent to host group G from all BUT a specific set of sources.
Such support
Support for source filtering is provided by version 3 of the Internet
Group Management Protocol (or IGMPv3) [IGMPv3] for IPv4, and version 2
of the Multicast Listener Discovery (or MLD) MLDv2) [MLDv2] protocol for
IPv6 [MLDv2].
IPv6. We shall henceforth refer to these two protocols as
"SFM-capable". "SFM-
capable". Earlier versions of these protocols - IGMPv1/IGMPv2 and
MLDv1 - do not provide support for source-filtering, and are referred
to as "non-SFM-capable". Note that while SFM is a different model than
ASM from a receiver standpoint, there is no distinction between the
two for a sender.

For the purpose of this document, we treat the scoped multicast model of
[RFC2365] to be a variant of ASM since it does not explicitly restrict
the number of sources, but only requires that they be located within the
scope zone of the group.

2. The IGMP/PIM-SM/MSDP/MBGP Architecture Protocol Suite for ASM

All

As of this writing, all multicast-capable networks of today support the ASM
service model. One of the most common multicast protocol architectures suites for
supporting ASM in wide-area backbones consists of IGMP version 2 [IGMPv2], PIM-SM [PIM-SM,PIM-SM-NEW], [PIM-
SM,PIM-SM-NEW], MSDP [MSDP] and MBGP [MBGP] protocols. To become a member of a particular host group end-hosts
report multicast group membership with querier routers handling
multicast group membership function using the IGMP version 2 (IGMPv2)
protocol IGMPv2
[RFC2236] for IPv4 or is the MLD version 1 (MLDv1) most commonly used protocol
[RFC2710] for IPv6. Routers then exchange messages with each other
according hosts to specify
membership in a routing protocol to construct a distribution tree
connecting multicast group, and nearly all multicast routers
support (at least) IGMPv2. In case of IPv6, MLDv1 [RFC2710] is the end-hosts. A
commonly used protocol.

Although a number of different protocols such as PIM-DM [PIM-DM], CBT
[RFC2189,RFC2201], DVMRP [IPMULTICAST], etc. exist for building
multicast forwarding trees, which differ mainly in the
type of delivery tree constructed [IPMULTICAST,PIM-ARCH, PIM-SM, PIM-
SM-NEW, PIM-DM]. For scalability reasons, sparse-mode protocols
(e.g., PIM-SM) are preferred over dense-mode protocols (e.g., DVMRP,
PIM-DM) for deployment among all receivers and sources in large backbone networks (though many
smaller networks deploy dense-mode protocols). PIM-SM, the same
administrative domain, PIM-SM [PIM-SM, PIM-SM-NEW] is the most widely
deployed sparse-mode protocol,
used protocol. PIM-SM builds a spanning multicast tree rooted at a
core rendezvous point or RP for all group members within a single
administrative domain. Multicast sources within this domain
send their data A 'first-hop' router adjacent to this a multicast
source sends the source's traffic to the RP for its domain. The RP which
forwards the data down the shared spanning tree to all interested
receivers within the domain. PIM-SM also allows receivers to switch
to a source-based shortest path tree.

As of this writing, multicast end-hosts with SFM capabilities are not
widely available. Hence a client can only specify interest in an
entire host group and receives data sent from any source to this
group. PIM-SM also allows
receivers to switch to

Inter-domain multicast service (i.e., where at least one source for a source-based shortest path tree.
multicast group is located in a different domain than the receivers)
requires additional protocols - MSDP [MSDP] and MBGP [MBGP] are the
most commonly used ones. An RP uses the MSDP [MSDP] protocol to
announce multicast sources to RPs in other domains. When an RP
discovers a source in a different domain transmitting data to a
multicast group for which there are interested receivers in its own
domain, it joins the shortest-path source based tree rooted at that
source. It then redistributes the data received to all interested
receivers via the intra-domain shared tree rooted at itself.

The MBGP protocol [MBGP] defines extensions to the BGP protocol [BGP]
to support the advertisement of reachability information for
multicast routes. This allows an autonomous system (AS) to support
incongruent unicast and multicast routing topologies, and thus
implement separate routing policies for each.

3. Problems with Current Architecture

There are several deployment problems associated with current
multicast architecture:

A) Inefficient handling of well-known sources :

In cases where the address of the source is well known in advance
of the receiver joining the group, and when the shortest
forwarding path is the preferred forwarding mode, then shared tree
mechanisms and MSDP are not necessary.

B) Lack of access control :

In the ASM service model, a receiver can not specify which
specific sources it would like to receive when it joins a given
group. A receiver will be forwarded data sent to a host group by
any source.

C) Address Allocation :

Address allocation is one of core deployment challenges posed by
the ASM service model. The current multicast architecture does not
provide a deployable solution to prevent address collisions among
multiple applications. The problem is more much less serious for IPv4 than IPv6
than for IPv4 since the total number size of the multicast addresses address space is smaller.
much larger. A static address allocation scheme, GLOP [GLOP00]
has been proposed as an interim solution for IPv4; however, GLOP
addresses are allocated per registered AS, which is inadequate in
cases where the number of sources exceeds the AS numbers available
for mapping. Proposed longer-term solutions such as the Multicast
Address Allocation Architecture [MAAA] are generally perceived as
being too complex (with respect to the dynamic nature of multicast
address allocation) for widespread deployment.

B) Lack of Access control :

In the ASM service model, a receiver cannot specify which
specific sources it would like to receive when it joins a given
group. A receiver will be forwarded data sent to a host group by
any source. Moreover, even when a source is allocated a multicast
group address to transmit on, it has no way of enforcing that no
other source will use the same address. This is true even in the
case of IPv6, where address collisions are less likely due to the
much larger size of the address space.

C) Inefficient handling of well-known sources :

4. Source Specific Multicast (SSM) : Benefits and Requirements

As mentioned before, the Source Specific Multicast (SSM) service
model defines a "channel" identified by an (S,G) pair, where S is a
source address and G is an SSM destination address. Channel
subscriptions are described using an SFM-capable group management
protocol such as IGMPv3 or MLDv2. Only source-based forwarding trees
are needed to implement this model.

The SSM service model alleviates all of the deployment problems
described earlier :

4.1 SSM lends itself to an elegant solution to the access control
problem. When a receiver subscribes to an (S,G) channel, it
receives data sent by a only the source S. In contrast, any host
can transmit to an ASM host group. Hence, it is more difficult to
spam an SSM channel than an ASM host group.

4.2

A) Address Allocation : SSM defines channels on a per-source
basis, i.e., the channel (S1,G) is distinct from the channel
(S2,G), where S1 and S2 are source addresses, and G is an SSM
destination address. This averts the problem of global allocation
of SSM destination addresses, and makes each source independently
responsible for resolving address collisions for the various
channels that it creates.

4.3

B) Access Control : SSM lends itself to an elegant solution to the
access control problem. When a receiver subscribes to an (S,G)
channel, it receives data sent by a only the source S. In
contrast, any host can transmit to an ASM host group. At the same
time, when a sender picks a channel (S,G) to transmit on, it is
automatically ensured that no other sender will be transmitting on
the same channel (except in the case of malicious acts such as
address spoofing). This makes it much harder to "spam" an SSM
channel than an ASM multicast group.

C) Handling of well-known sources : SSM requires only source-based
forwarding trees; this eliminates the need for a shared tree
infrastructure. In terms of the IGMP/PIM-SM/MSDP/MBGP protocol
suite, this implies that neither the RP-based shared tree
infrastructure of PIM-SM nor the MSDP protocol is required. Thus
the complexity of the multicast routing infrastructure for SSM is
low, making it viable for immediate deployment.

4.4 Note that MBGP is
still required for distribution of multicast reachability
information.

D) It is widely held that point-to-multipoint applications such as
Internet TV will dominate the Internet multicast application
space be important in the near future. The SSM model is
ideally suited for such applications.

5. SSM Framework

Figure 1 illustrates the elements in an end-to-end implementation
framework for SSM :

--------------------------------------------------------------
IANA assigned 232/8 for IPv4 ADDRESS ALLOCATION
FF3x::/12 for IPv6
--------------------------------------------------------------
|
v
+--------------+ session directory/web page
| source,group | SESSION DESCRIPTION
--------------------------------------------------------------
^ |
Query | | (S,G)
| v
+-----------------+ host
| SSM-aware app | CHANNEL DISCOVERY
--------------------------------------------------------------
| SSM-aware app | SSM-AWARE APPLICATION
--------------------------------------------------------------
| IGMPv3/MLDv2 | IGMPv3/MLDv2 HOST REPORTING
+-----------------+
|(source specific host report)
--------------------------------------------------------------
v
+-----------------+ Querier Router
| IGMPv3/MLDv2 | QUERIER
--------------------------------------------------------------
| PIM-SSM | PIM-SSM ROUTING
+------------+ Designated Router
|
| (S,G) Join only
v
+-----------+ Backbone Router
| PIM-SSM |
+-----------+
|
| (S,G) Join only
V

Figure 1 : SSM Framework: elements in end-to-end model

We now discuss the framework elements in detail :

5.1 Address Allocation

For IPv4, the address range of 232/8 has been assigned by IANA for
SSM. To ensure global SSM functionality in 232/8, including in
networks where routers run non-SFM-capable protocols, operational
policies are being proposed [SSM-BCP] which prevent data sent to
232/8 from being delivered recommend that routers
should not send SSM traffic to parts of the network that do not have
channel subscribers.

Note that IGMPv3/MLDv2 does not limit (S,G) joins to only the 232/8
range. However, SSM service, as defined in [SSM-ARCH], is guaranteed available
only in this address range for IPv4.

In case of IPv6, [HABE1] has defined an extension to the addressing
architecture to allow for unicast prefix-based multicast addresses.
In this case, bytes
Bytes 0-3 (starting from the least significant byte) of the IP
address is are used to specify a multicast group id, bytes 4-11 is
be are used
to specify a unicast address prefix (of up to 64 bits) that owns this
multicast group id, and byte 12 is used to specify the length of the
prefix. A source-specific multicast address can be is specified by setting
both the prefix length field and the prefix field to zero.

5.2 Session Description and Channel Discovery

An SSM receiver application must know both the SSM destination
address G and the source address S before subscribing to a
channel. Thus the function of channel Channel discovery becomes is the responsibility of applications.
This information can be made available in a number of ways,
including via web pages, sessions announcement applications, etc. The
This is similar to what is used for ASM applications where a
multicast session needs to be announced so that potential
subscribers can know of the multicast group adddres, encoding
schemes used, etc. In fact, the only additional piece of
information that needs to be announced is the source address for
the channel being advertised. However, the exact mechanisms for
doing this is outside the scope of this framework document.

5.3. SSM-Aware Applications

-- For applications sourcing content via An application that wants to received an SSM channels, the session must be advertised including a source first
discover the channel address as well as an SSM
address. in use. Any of the mechanisms
described in Section 5.2 can be used for this purpose.

-- Applications expecting to subscribe to an SSM channel A receiving application must be
capable of specifying able to specify both a source
address in addition to an SSM and a destination address. address to the network layer protocol
module on the end-host. In other words, the application must be "SSM-
aware".
"SSM-aware".

Specific API requirements are identified in [THAL00]. [THAL00]
describes a recommended application programming interface for a
host operating system to support the SFM service model. Although
it is intended for SFM, a subset of this interface is sufficient
for supporting SSM.

5.4. IGMPv3/MLDv2 Host Reporting and Querier

IGMP version 2 [IGMPv2] allows end-hosts to report their interest
in a multicast group by specifying a class-D IP address for IPv4.
However in

In order to implement the use SSM service model, service, an end-host must be able to specify a
channel address, consisting of a source's unicast address as well as and an
SSM destination address. This capability IGMP version 2 [IGMPv2] and MLD version 1
[MLDv1] allows an end-host to specify only a destination multicast
address. The ability to specify an SSM channel address c is
provided by IGMP version 3
[IGMPv3]. IGMPv3 supports [IGMPv3] and MLD version 2 [MLDv2].
These protocols support "source filtering", i.e., the ability of
an end-system to express interest in receiving data packets sent
only by SPECIFIC sources, or from ALL BUT some specific sources.
Thus,
In fact, IGMPv3 provides a superset of the capabilities required
to realize the SSM service model.

There are a number of backward compatibility issues between IGMP
versions 2 and 3 which have to be addressed.

A detailed discussion of the use of IGMPv3 in the SSM destination
address range is provided in [SSM-IGMPv3].

The Multicast Listener Discovery (MLD) protocol used by an IPv6
router to discover the presence of multicast listeners on its
directly attached links, and to discover the multicast addresses
that are of interest to those neighboring nodes. Version 1 of MLD
[DEER99] is derived from IGMPv2 and allows a multicast listener
to specify does not provide the multicast group(s) that it is interested in. source
filtering capability required for the SSM service model. Version 2
of MLD [VIDA01] is derived from, and provides the same support for
source-filtering as, IGMPv3. THus IGMPv3 (or MLDv2 for IPv6)
provides a host with the ability to request the network for an SSM
channel subscription.

5.5. PIM-SSM Routing

PIM-SM

[PIM-SM-NEW] itself supports two types of trees, a shared tree
rooted at a core (RP), and provides guideliness for how a source-based shortest path tree. Thus
PIM-SM already supports source-based trees. The original PIM-SM [PIM-SM] implementation
should handle source-specific host reports as required by SSM.
Earlier versions of the PIM protocol specifications did not allow a router to choose between a shared
tree and a source-based tree. In fact, a receiver always joined a PIM
shared tree to start with, and may later be switched describe
how to a per-source
tree by its adjacent edge router. However, the more recent PIM-SM
specification [PIM-SM-NEW] has support do this.

The router requirements for source-specific join.

Supporting operation in the SSM range are detailed
in [SSM-ARCH]. These rules are primarily concerned with PIM-SM involves preventing
ASM-style behaviour in the SSM address range. In order to comply with
[SSM-ARCH] several changes to the PIM-SM protocol are required, as
described in [PIM-SM-NEW]. The resulting PIM functionality is
described as PIM-SSM. The specific architectural issues associated
with PIM-SSM and IGMPv3/MLDv2 are detailed in [SSM-ARCH]. The [PIM-SM-NEW].The most important changes to in PIM-SM
required for compliance with respect to SSM [SSM-ARCH] are as follows: :

-- When a DR receives an (S,G) join request with the address G in
the SSM address range, it must initiate a (S,G) join and NEVER a
(*,G) join.

--Backbone routers (i.e. routers that do not have directly
attached hosts) must not propagate (*,G) joins for group addresses
in the SSM address range.

--Rendezvous Points (RPs) must not accept PIM Register messages or
(*,G) Join messages in the SSM address range.

Note that only a small subset of the full PIM-SM protocol
functionality is needed to support the SSM service model. This subset
is explicitly documented in [PIM-SM-NEW].

6. Interoperability with Existing Multicast Service Models

Interoperability with ASM is one of the most important issues in
moving to SSM deployment. ASM and SSM will always coexist; hence
there will be two service deployment, since both models for Internet multicast. are expected to be used
at least in the foreseeable future. SSM is the ONLY service model for
the SSM address range - the correct protocol behaviour for this range
is specified in [SSM-ARCH]. The ASM service model will be offered for
the non-SSM adddress range, where receivers can issue (*,G) join
requests to receive multicast data. A receiver is also allowed to
issue an (S,G) join request in the non-SSM address range; however, in
that case there is no guarantee that it will receive service
according to the SSM model.

Another backward compatibility interoperability issue concerns the MSDP protocol, which is
used between PIM-SM rendezvous points (RPs) to discover multicast
sources across multiple domains. SSM obviates the needs MSDP is not needed for
MSDP, SSM, but MSDP is still required to support
needed if ASM for non-SSM class-D
IPv4 addresses. In order is supported. [SSM-BCP] specifies operational
recommendations to help ensure that SSM is MSDP does not interfere with the sole forwarding
model in 232/8,
ability of a network to support the SSM service model. Specifically,
[SSM-BCP] states that RPs must not accept, originate or forward MSDP
SA messages for the SSM address range [SSM-BCP].

7. Security Considerations

SSM does not introduce new security considerations for IP multicast.
It can help in preventing denial-of-service attacks resulting from
unwanted sources transmitting data to a multicast channel (S, G).
However no guarantee is provided.

8. Acknowledgments

We would like to thank Gene Bowen, Ed Kress, Bryan Lyles, Sue Moon Lyles and Timothy
Roscoe at Sprintlabs, Hugh Holbrook, Isidor Kouvelas, Tony Speakman
and Nidhi Bhaskar at Cisco Systems for participating in lengthy
discussions and design work on SSM, and providing feedback on this
document. Thanks are also due to Mujahid Khan and Ted Seely at
SprintLink, Tom Pusateri at Juniper Networks, Bill Fenner at AT&T
Research, Kevin Almeroth at the University of California Santa
Barbara, Brian Levine at the University of Massachusetts Amherst,
Brad Cain at Cereva Networks and Hugh LaMaster at NASA for their
valuable insights and continuing support.

9. References:

[EXPRESS] H. Holbrook and D.R. Cheriton. IP Multicast Channels :
EXPRESS Support for Large-scale Single-Source Applications. In
Proceedings of SIGCOMM 1999.

[IANA-ALLOCATION] Internet Assigned Numbers Authority.
http://www.isi.edu/in-notes/iana/assignments/multicast-addresses.

[RFC2236] W. Fenner. Internet Group Management Protocol, Version 2.
Request For Comments 2236.

[IGMPv3] B. Cain and S. Deering, I. Kouvelas and A. Thyagarajan.
Internet Group Management Protocol, Version 3. Work in Progress.

[SSM-IGMPv3] H. Holbrook and B. Cain. IGMPv3 for SSM. Work in
Progress.

[SSM-ARCH] H. Holbrook and B. Cain. Source-Specific Multicast for
IP. Work in Progress.

[IPMULTICAST] S. Deering and D. Cheriton. Multicast Routing in
Datagram Networks and Extended LANs. ACM Transactions on Computer
Systems, 8(2):85-110, May 1990.

[PIM-ARCH] S. Deering et al. PIM Architecture for Wide-Area
Multicast Routing. IEEE/ACM Transaction on Networking, pages 153-162,
April 1996.

[PIM-SM] D. Estrin et al. Protocol Independent Multicast - Sparse
Mode (PIM-SM) : Protocol Specification. Request for Comments, Comments 2362.

[PIM-SM-NEW] B. Fenner, M. Handley, H. Holbrook, I. Kouvelas.
Protocol Independent Multicast - Sparse Mode (PIM-SM): Protocol
Specification (Revised)", Work In Progress, 2000. <draft-ietf-pim-
sm-v2-new-01.txt>.

[PIM-DM] S. Deering et al. Protocol Independent Multicast Version 2
Dense Mode Specification. Work in Progress.

[RFC2189] A. Ballardie. Core-Based Trees (CBT Version 2) Multicast
Routing -- Protocol Specification. Request for Comments 2189.

[RFC2201] A. Ballardie. Core-Based Trees (CBT) Multicast Routing
Architecture. Request for Comments 2201.

[RFC2365] D. Meyer. Adminstratively Scoped IP Multicast. Request for
Comments 2365.

[MSDP] Farinacci et al. Multicast Source Discovery Protocol. Work in
Progress.

[MAAA] M. Handley, D. Thaler and D. Estrin. The Internet Multicast
Address Allocation Architecture. Work in Progress (draft-ietf-
malloc-arch-**.txt) June 2000.

[MCAST-DEPLOY] C. Diot, B. Levine, B. Lyles, H. Kassem and D.
Balensiefen. Deployment Issues for the IP Multicast Service and
Architecture. In IEEE Networks Magazine's Special Issue on
Multicast, January, 2000.

[SSM-RULES] H. Sandick and B. Cain. PIM-SM Rules for Support of
Single-Source Multicast. Work in Progress.

[MSF-API] Dave Thaler, Bill Fenner and Bob Quinn. Socket Interface
Extensions for Multicast Source Filters. Work in Progress.

[RFC2770] GLOP Addressing in 233/8. Request For Comments 2770.

[RCVR-INTEREST] B. Levine et al. Consideration of Receiver Interest
for IP Multicast Delivery. In Proceedings of IEEE Infocom, March
2000.

[SSM-BCP] G. Shepherd et al. Source-Specific Protocol Independent
Multicast in 232/8. Work in Progress.

[RFC2710] S. Deering, W. Fenner and B. Haberman. Multicast Listener
Discovery for IPv6. Request for Comments 2710.

[MLDv2] R. Vida, et. al.
Multicast Listener Discovery Version 2 (MLDv2) for IPv6.
Work in progress.

[SSM-IPv6] B. Haberman and D. Thaler.
Unicast-Prefix-Based IPv6 Multicast Addresses. Work in
Progress.

[IPSEC] S. Kent, R. Atkinson.
Security Architecture for the Internet Protocol. Request for
Comments 2401.

[IPv6-ALLOC] B. Haberman.
Dynamic Allocation Guidelines for IPv6 Multicast Addresses.
Work in Progress.

12. Authors' Address:

Supratik Bhattacharyya
Christophe Diot
Sprint Advanced Technology Labs
One Adrian Court
Burlingame CA 94010 USA
{supratik,cdiot}@sprintlabs.com
http://www.sprintlabs.com

Leonard Giuliano
Greg Shepherd
Juniper Networks, Inc.
1194 North Mathilda Avenue
Sunnyvale, CA 94089 USA
{lenny,shep}@juniper.net

Robert Rockell
David Meyer
Sprint E|Solutions
Reston Virginia USA
{rrockell,dmm}@sprint.net

John Meylor
Cisco Systems
San Jose CA USA
jmeylor@cisco.com

Brian Haberman
No Affiliation
haberman@innovationslab.net