[SAM] IETF-71 meeting for SAM RG

[John Buford]

Xiaoming,

Thanks for raising these points.  Please see the separate email on
SAM RG 2007 report for a partial answer to the question,
where are we now?

Let me give my personal views to some of your questions below.

John

On Jan 3, 2008 10:52 AM, Xiaoming Fu <fu at cs.uni-goettingen.de> wrote:

> Dear all,
>
> As a RG member I have one, probably more general question: where we are
> now and where we are going within the RG? In the past few months (since
> IETF#69) the technical discussion was somewhat dormant in the mailing
> list, nor there is an active ID on SAM, therefore I have been wondering
> this question - or more specifically, a set of subquetions below:
>
> http://www.samrg.org states that
> "The Scalable Adaptive Multicast (SAM) Research Group invetigates
> multicast protocols including application layer multicast (ALM), overlay
> multicast (OM), native multicast, and hybrid techniques with the goal of
> greater scalabality and adaptability in terms of numbers of multicast
> groups and network resources. It also provides input for standardization
> efforts within the IETF."
> "The Scalable Adaptive Multicast (SAM) Research Group is chartered to
> explore and research techniques which improve multicast performance with
> respect to dimensions such as number of groups, dynamics of group
> membership, dynamics of the network topology, and network resource
> constraints. The RG will investigate approaches based on application
> layer multicast (ALM), overlay multicast (OM), and native IP multicast,
> as well as hybrid approaches."
>
> --> This indicates that, analysis of existing non-IP multicast
> approaches would be a GOAL. I have somehow sensed this as possible RG
> item but no team work being taken nor active draft at least from what I
> know for now.



I agree it is it a goal.  We also know that a few research publications have
compared several leading ALM/OM designs already.  Most of these
comparisons have been done through simulations.  This requires
a simulation environment that has a realistic network topology and can
scale to large number of end systems.  What simulation environment do
people think we should adopt in the RG?  The ones I could recommend
from personal familiarity are SSFNet and OverSim.



>
>
> "A key design consideration is the placement of multicast state
> information along the multicast path, including packet headers, end
> hosts, and network nodes, where placement may be determined adaptively."
>
> --> This implies that the placement of MC state information could be
> dynamic, which does not tell what we should do.
>
> "In SAM architectures, new protocols are expected to coexist and
> integrate with native IP multicast protocols while offering more
> flexible deployment options and scaling to support a greater number of
> simultaneous multicast groups. Alternative technologies such as
> end-system multicast and overlay multicast have been demonstrated, but
> these mechanisms must be integrated into a unified architecture and
> operational design."
>
> --> this implies a new (or called "unified") architecture will be
> defined within the RG. Maybe I am missing something, but where is an
> architecture or prototypical idea?


Please see the SAM framework draft.  It was discussed in the IETF-69
meeting and the slides are on-line.  The basic idea is to partition the
Internet into domains of different categories of native multicast and ALM
support,
and use an extension to AMT gateways to bridge these domains.  This has the
advantage of leveraging the AMT work which is already being supported
by several vendors and for which open source implementations exist.
However AMT doesn't deal with ALM, only native multicast.  Hence the
extensions.



>
>
> "Among the challenges to be addressed are: multicasting in topologies
> with concatenated VPNs, such as the Global Information Grid (GIG);
> ability to incorporate QoS mechanisms while retaining scalability;
> integration with network- and application-layer security mechanisms; and
> adaptation schemes which consider group-related factors, such as group
> size, number of sources, membership dynamics, sensitivity to delay,
> amount of state, state update rate, application data rate, and other
> application-specific parameters, as well as network-related factors,
> such as dynamics of topology, carrying capacity, and connectivity."
> --> This looks to me we aim to define evaluation metrics and make a
> systematic evaluation for various existing (non-IP) multicast proposals?


I think this is saying that the SAM Framework should be evaluated under
a variety of interesting dimensions.  Are new metrics needed?  Perhaps.
There are already various metrics in use, but these haven't been used
in the context of all these dimensions listed above.

Also, I don't expect to see VPN/GIG multicast work happening in the near
term
since it is not clear how much progress is being made on the GIG itself.


>
>
> "Methods will be explored for group formation and discovery that scale
> to large numbers of groups, accommodate highly dynamic group membership,
> and support user-initiated small-group multicast in which the group is
> defined as a set of explicitly addressed endpoints. Further challenges
> include efficient multicast for limited-resource nodes and access links,
> control mechanisms for hybrid systems, approaches to optimization in the
> network, including routing, and operation in mobile networks, including
> Mobile Ad-hoc Networks (MANETs)."
>
> --> My interpretation would be that SAMRG intends to take group
> management into account and consider multicast over specific scenarios.
> For the former, I didn't recall much ML discussion on the design space;
> For the later if I remember it correctly there is an ID (actually a
> group of IDs) on mobile multicast recently and even discussed in last
> IETF, would people here be interested on this and like to explore more
> details?


There have been no proposals in the RG that I can remember on ALM in mobile
P2P,
I don't think there has been much work on this in general.


>
>
> "Deploying, diagnosing, debugging, and managing multicast services is
> complex, particularly for services which span multiple administrative
> domains. The RG will propose and evaluate tools and strategies for
> deployment, operations, and management of SAM services."
>
> --> I would rather see some document(s) and more discussions on
> operational experiences on IPTV and  multicast deployments in the
> Internet. This may allow better understanding of the customers' need and
> what are the real operational requirements/constraints. Again question
> is: would people here be interested in contributing and discussing their
> related work/experiences to the RG?


Sure, all operational experience is useful.


>
>
> "The RG will select candidates for analysis and evaluation from existing
> research results. Researchers are invited to submit new approaches for
> further investigation. Through experimentation, the RG seeks to deepen
> its understanding of the solution space and to enable the identification
> of preferred solutions as a function of dynamic network characteristics
> and the number of multicast sources, receivers, and groups."
> --> Well, we probably have some good starts in turns of evaluation of
> existing works, but not much extended and reviewed in the RG - or I am
> missing any active editors?


More contributions in all areas of the SAM work areas including evaluations
would be a good thing.


>
>
> "The expected findings of the RG include characterizing the problem
> space, including driving scenarios, comparisons and analysis of existing
> approaches, a SAM framework that supports multiple ALM/OM/ native/hybrid
> protocols, analysis of network infrastructure impact when multicast
> traffic becomes a dominant flow in a network, and deployment scenarios
> which are independent of but can support and evolve with network
> infrastructure support for native multicast. The findings are expected
> to be published in technical reports, academic papers, and/or RFCs."
> --> This sounds reasonable scoping, but I cannot resist ask myself:
> where are we now? Maybe it would be helpful if we could make the future
> work agenda more clearly expressed, by defining RG (at least some
> mid-term) milestones and soliciting active contributors (esp.
> corresponding editors) for each of the work items, e.g., (roughly
> sequentially in time but may overlay):
>
> * A survey of existing non-IP multicast approaches (btw - did any
> RG/IAB/IETF WG publish a survey on existing IP multicast protocols?


There are a few publications on surveying IP multicast protocols, but not
clear
if these were organized by an WG/RG.



>
> RFC3569? Otherwise, I would suggest also to look at IP multicast
> protocols too as another potential work item) - Informational
> * Evaluation metrics of multicast approaches - Informational
> * An evaluation of Internet multicast approaches - Informational
> * A SAM framework for interworking (?) between different multicast
> approaches - Informational
> * Operational experience of IPTV services (or IPTV operational
> practices) - Informational
> * Experience with the xxx Protocol - Informational (or BCP?)
> * (Suggestions for) Multicast in mobile IP(v6) environments (or some
> other scenarios) - Informational
> etc.


I think there are enough WGs doing native multicast work already,
but hybrid schemes are in scope for the RG.

>
>
> My 0.02 cents
> Cheers,
> Xiaoming


Thanks for the comments.  Please attend the IETF 71 meeting and
participate in the agenda.

John




>
>  Forest.Lin wrote:
> > Hi,  I want to ask u a question , that is , when the sam-tk project can
> > release the first version on http://sourceforge.net/projects/samtk ?
> thx!
> >
> > ------------------------------------------------------------------------
> > Forest.Lin
> > 2008-01-03
> > ------------------------------------------------------------------------
> > *·¢¼þÈË£º* Eiichi Muramoto
> > *·¢ËÍʱ¼ä£º* 2008-01-03 15:35:14
> > *ÊÕ¼þÈË£º* buford at samrg.org
> > *³­ËÍ£º* sam at irtf.org; xcast at wide.ad.jp
> > *Ö÷Ì⣺* Re: [SAM] IETF-71 meeting for SAM RG
> >
> > John-san
> >
> > We would like to have presentation below at the BoF of SAM in IETF71
> >
> > - Tutorial of SAM-TK ( by Nobuo Kawaguchi of Nagoya Univ.)
> > - ALM API for Topology Management and
> >   Network Layers Transparent Multimedia Streaming
> >   (by Lim Boon Ping of Panasonic Kuala Lumpur Lab)
> > - XCAST 1.0 and 2.0 ( by Yuji -UG- Imai of WIDE )
> >
> > I think 15 min for each is enough.
> >
> > Best Regards,
> > Eiichi Muramoto
> >
> > On Wed, 2 Jan 2008 13:53:40 -0500
> > "John Buford"  <buford at samrg.org > wrote:
> >
> >  > We plan to hold a meeting of the SAM RG at IETF-71 in Philadelphia.
> >  >
> >  > When the exact date of the meeting is available, we will post to the
> mail
> >  > list.
> >  >
> >  > Please post requests for agenda items to the mail list.
> >  >
> >  > Thank you,
> >  >
> >  > John Buford & Jeremy Mineweaser
> >
> > --
> > Eiichi Muramoto  <muramoto.eiichi at jp.panasonic.com >
> >
> >
> >
>
>
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>
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