MEMORANDUM of UNDERSTANDING
For the implementation of a European Concerted Research Action
designated as COST Action 264
Title : Enabling Networked Multimedia Group Communication
The Signatories of this Memorandum of Understanding, declaring their common
intention to participate in the Concerted Action referred to above and
described in the Technical Annex to the Memorandum, have reached the
following understanding :
- The Action will be carried out in accordance with the provisions
of the document COST/400/94 _Rules and Procedures for
Implementing COST Actions", the contents of which the
Signatories are fully aware of.
- The main objectives of the action are to enable the cooperation
of scientists in Europe involved in the design of the
architecture and applications related to group communication.
Results will be made available to the signatories as well as to
the industry. Also, contributions will be send to
standardization bodies. Another primary goal will be to
experiment solutions and
applications on a Mbone type of network and provide
recommendations on how such a network can be enhanced.
- To this end a cooperative effort involving universities as well as
telecommunication R&D establishments and industries is required.
- The overall cost of the activities carried out under the Action has
been estimated, on the basis of information available during the
planning of the Action, at 5.75 MEcus at 1997 prices.
- The Memorandum of Understanding will take effect on being signed by
at least five Signatories.
- The Memorandum of Understanding will remain in force for a period of
4 years, unless the duration of the Action is modified according to the
provisions of Chapter 6 of the document referred to in Point 1 above.
COST Action 264
Enabling Networked Multimedia Group Communication
The work carried out within various projects including COST237 has
demonstrated the importance of multimedia group communication for
enabling high-performance networking and new emerging applications. One
can mention multiparty conferencing, Internet telephony, collaborative
work or distributed interactive simulation. They are characterized by
interactivity, real-time constraints, and various number of
participants. Obviously, all these applications require multipeer
functionalities that are not currently available as a basic service. It
has been recognized that providing both multipeer capabilities as well
as quality of service in various forms is not achieved no matter what
technology is considered, i.e : ATM, IP, mobile networks, satellites,
etc. Moreover, it was shown that there is a lack of practical
understanding and experience in this area, mainly because no
experimental network is available in Europe. The only existing
infrastructure is the experimental Mbone (overlay multicast network on
the Internet) ; but it is not satisfactory as it does not provide any
transmission control facility (congestion/flow control, reliability,
Quality of Service, group and address management, etc.). Nowadays, there
exists an increasing demand and a large potential market for multimedia
multipeer applications that justify the development of an efficient
European multicast network infrastructure.
The objective of this action is to build up on the COST 237 results
(Multimedia Telecommunications Services) to bring together European
research teams involved in group communication both from the
infrastructure and application perspective. They will cooperate in order
to identify solutions for the improvement of the multipeer communication
architecture, including application, communication mechanisms, and
infrastructure. This area is becoming of utmost strategic importance
both from the research and industrial perspective. An incredible amount
of work is done in this domain in the USA and Japan. Some work is also
visible in Europe but with a lack of coordination and dissemination of
results to the academic and industrial world. This is enforced by the
need of experimentation on a multicast network to develop and assess
B) Objectives and benefits
The main objective of this action will be to provide a forum where
researchers and industrials active in this area will participate.
Complementary experimentations will be conducted to enable and
understand multimedia group communications that will be available on
various networks in the future. These activities will contribute to
leverage European research in this domain as well as to the development
of enhanced architectures at the International level.
The action will be divided into two complementary parts of similar
importance, that together will enable the action to meet its goals :
The " infrastructure and dissemination " part aims at cooperation and
coordination between research actors to improve the existing
infrastructure to support group communication (principally the Mbone).
The infrastructure activity is a pre-requisite to the scientific
cooperation. It will allow experimentation with the applications and
mechanisms developed by participants, as well as providing a way to
support an effective dissemination of the work. This activity will:
- Infrastructure and dissemination.
- Research and experimentation.
The " research and experimentation " part is devoted to cooperation
between participants in the areas of multicast, multipeer, group
communication and relevant applications. This is an area of utmost and
strategic importance for research and industry. Multimedia group
communication will leverage industry competitivity and provide new tools
for cooperative work. This activity will:
- Create a multicast group on the Mbone (named the "Costbone")
dedicated to this action and to the European networking research
- Coordinate work to improve the infrastructure based on the
- Define and support an homogeneous environment in the sites
connected on the Costbone to fulfill the requirements for distributed
- Disseminate the action activity through euro-seminars and other
forms (multiparty conferencing, telephony, Collaborative work, etc.).
Both activities are tightly coupled and converge to :
- Bring together European teams already involved in the area of group
communication to discuss research activities, identify key issues and
potential solutions, and therefore benefit from cross-fertilization.
- Invite people from industry to whom these technologies will be very
important in the near future, to describe their needs and expectations.
- Evaluate the work carried out in the different standardization or
project bodies and provide feedback as users and researchers to the
standardization groups (in particular to IETF).
- Discuss solutions through meetings (including electronic meetings over
- Experiment new multipeer transmission control algorithms and
mechanisms designed by the action's participants. Evaluate
experimentally the proposed solutions on the available infrastructure
- Provide a framework for the exchange of research scientists and
students in order to improve the level of collaboration between research
A technical report that describes the progress made in the area of group
communication thanks to the action activity. This report will be
published as a book or as a special issue of a technical journal .
Benefits, as described above, will be an understanding of the issues to
enable group communication that appears as a challenging research area
as well as an emerging market. It will organize the research community
involved in these areas and disseminate the results outside the action
participants (academic and industry). Finally, the action should have an
influence on the standardization activities in this domain.
Recommendations on how to use the results achieved in the action and
solutions to enhance the Mbone will be provided.
According to the issues mentioned above, the action will deliver and
emphasize on the following results :
- manage and experiment distributed multimedia applications,
- dissemination through Euro-seminars,
- design new solutions (algorithms and mechanisms) for multipeer
- report action results to major standardization bodies,
- deliver a final report published as a book or as a special issue of a
- identify solutions to enhance the Mbone infrastructure.
C) Technical program
The action will enable a strong and permanent cooperation and
coordination between the actors from different perspectives, mainly
technical but also through experimentations that are of utmost
importance when group communication is involved. The action goals are on
one hand to identify the problems encountered with group communication
(and propose solutions to these problems), and on the other hand to make
a " well-behaved " multicast backbone comes true to support experiments,
allow fast and easy dissemination of results and support
C.1. Research and experimentation
Group communication is recognized as a new paradigm that requires a deep
modification of the networking functions, mechanisms and protocols
designed with only " unicast " communication in mind. The action
participants are already involved in this research. The following are
currently addressed :
Naming and addressing.
In the current Internet, multicast address allocation is done on a
random basis. With group communication becoming popular, and
applications using more than one group per session, it becomes urgent to
define hierarchical address allocation schemes together with a unified
naming strategy. Both will improve error control and congestion control
by providing a simple and efficient way to select multicast addresses
and to identify objects within a data flow.
Today, there are three main approaches to error control in multicast:
local recovery, hierarchical recovery, and FEC. These three approaches
are nowadays deployed in many different experimental protocols, but
their specific advantages and disadvantages are not well understood.
These protocols have to be tested on a real platform to be qualified
regarding application characteristics and network dynamics.
Congestion control for multicast is an unsolved problem. There are two
approaches to multicast congestion control : Rate based control (such as
in TCP slow-start) and application based control (with techniques such
as layered multicast or media-scaling). Congestion control is being
studied in the Internet community as one of the compulsory mechanisms to
enable the wide deployment of multicast.
Scalability: group management.
Having all the participants of a session in the same group is neither
scalable, nor useful. The scalability problem is obvious. At the same
time, each participant does not need to receive all information coming
from all other participants. He will be mostly concerned by his
neighbors, by his allied, by people with the same communication medium,
etc. This will allow to subdivide the group of participants in
sub-groups with different constraints and attributes.. Solutions are
required to target very large group communication systems such as the
one encountered in applications like distributed games, distributed
interactive simulation, large scale document dissemination, etc. The
dynamic of the group activity as well as the management of the group
properties and semantic relationships between users will be addressed.
Multicast QoS capable architectures
The ability to support multipeer Quality of Service (QoS) will be
studied for various technologies available today or in the near future
such as IP, ATM, mobile networks, satellite networks or any kind of
heterogeneous technology. The mechanisms mentioned above will be
considered from the perspective of efficiency, network support or
The different technical issues described above are the foundation for
the design of a multipeer communication infrastructure. Research work in
this area requires a close cooperation of involved research groups in
order to be efficient and converge to a coherent solution.
C.2. Infrastructure and dissemination
The target of this activity is to identify how to improve the existing
infrastructure (mainly the Mbone) as well as provide the support for
distributed multimedia experimentations and action dissemination :
Contributing to the improvement of the infrastructure
The infrastructure is mandatory for the action to settle a continuous
efficient and active cooperation between the participants. It will also
add to the international credibility of the action, in particular in the
Internet community (IRTF and IETF). Improving the infrastructure will
allow research groups to experiment with their work in a wide-area
network, with the support of other European researchers.
The goal of this activity is to allow participants to share their
experience in local or Mbone environments and provide recommendations
and understanding to the deployment of an efficient infrastructure.
The action participants are already active in the research area of group
communication. However, anytime they want to experiment with their
algorithms and protocols, they face the problem of the lack of a robust
experimental network infrastructure. They also face the absence of
feedback from other research groups. This activity will have a direct
influence on the importance and on the credibility of the action
contributions. It will also allow the action to contribute, at the
highest scientific level, in a domain where the USA have dominated for
Dissemination of information:
Information dissemination is a key factor for efficient cooperation in
research. Solutions such as multiparty conferencing, telephony, and CSCW
(Cooperative Support for Collaborative Work), will be made available
through the Costbone. It will allow all European countries to profit
and/or to participate at their own technology level : as simple
participants or as researchers. Moreover, design, test, and distribution of
new multicast multimedia applications will be done through the entire
action life. The results of the action will be made available to a large
extend, to industry and research actors.
D) Organization and Timetable
The organization of the group will follow the standard form of Cost
actions with the following initiatives :
The duration of the action is 4 years.
- signatories are represented in the Management Committee (MC) by
- there will be two meetings a year and electronic meetings several
times a year,
- the action will seek the advice of the Technical Committee
Telecommunication (TCT) to achieve a working liaison between the action
and other related COST actions,
- dissemination though euro-seminars,
- a workshop will be organized once or twice per year in order to put
together the experts in the area of group communication,
- report action results to major standardization bodies, and in
particular to IRTF and IETF,
- continue the joint organization of the Ecmast conference (in the
continuation of COST237),
- exchange researchers or students,
- define and do joint experiments on the existing infrastructure
The action will start with two areas that will be activated through the
definition of working groups :
Area 1 : Research and experimentation
This area is targeting cooperation in important research issues in the
domain of group communication, as mentioned in section 3. It is a
technical area where we will discuss research activities carried out by
the action participants, as well as research done in other
organizations. It should become a major forum for research in Europe
covering aspects ranging from multicast mechanisms to application design
for group communication. Outputs will be delivered to standardization
bodies. Cooperation with industry will also be promoted within this
Area 2 : Infrastructure and dissemination
This area is responsible for the activity related to the part "
Infrastructure and dissemination " described above. It will consist in
sharing experience with the Mbone utilization, and to identify possible
improvements to the available infrastructure. This WG will be also in
charge of scheduling seminars, conferences and experiments on the
A tightly coupled liaison will be established between the two areas and
working groups will be defined to organize the related activities at the
early stage of the project. Also, new working groups might appear and
others get stopped if required by the evolution of the area and
participants. The operational management will build on the one
experimented for COST237.