Broadband Networks Activity

This activity deals with issues related to broadband communication networks. Important effort is dedicated to basic research in the above area, dealing with the accurate calculation of the cell-loss probability that occurs in the network under a particular load. We are developing and refining advanced methematical tools based on the theory of large deviations for the effective tools based on the theory of large deviations for the effective calculation of these extremely small probabilities under general assumptions on the network traffic. This general methodology also allows the fast on-line estimation of the desired QoS parameters by monitoring certain events occuring in the actual system. Related work is being carried in the area of effective bandwidths for variable bit rate traffic streams and their use in the management of the congestion and the usage-based procing of network services. Besides the above research, our group is also involved in the following research topics funded by ACTS projects.

The first topic, funded by the ACTS project CASHMAN, deals with developing sound and implementable pricing models for broadband network services. This is an extremely vital subject in modern telecommunications. More specificaly, out task is to study, develop, implement and verify charging and accounting schemes for ATM networks. These schemes are based on models that address needs such as fair charging according to effective usage of network resources, have low implementation cost, and lead to efficient usage of network resources. These models will be tested in field trials involving real users in a number of European National Host facilities, in order to access the effects of pricing to the user bahaviour regarding the use of the network services.

The second topic, funded by the RACE project ICM, concerns aspects of the architecture of the Telecommunications Management Network for the B-ISDN. In particular we are investigating and experimenting with the management requirements for virtual-path bandwidth assignment, virtual private networks, and QoS management. In addition to that, we are designing and implementing TMN components and extensions to platforms conforming to OSI standards, with advanced features such as directory services, location and distribution transparency. The design of the management components is compliant and extends ITU-TS recommendations. Many results of this activity are already submitted to the ATM Forum and the NM Forum.

A third topic, funded by the ACTS project MISA, deals with the management of broadband multipoint, multiple bit rate connections. The set-up and the re-configuration of such connections are currently performed through manual actions using the fax and the telephone. It is a vital task to automate the above procedures in order to satisfy the end-user requirements in a matter of seconds. This needs the provisioning of open interfaces to the management centres for the necessary cooperation between management systems. In addition to the above issues we also study the integrated management of ATM and SDH networks; this is a key issue because of the enormous potential benefit in optimising the use of the hybrid network resources. The validation of our approach will be based on international field trials in European National Host facilities.

A last topic of research, funded by the ACTS project REFORM, which is very related but distinct from the above concerns the problem of resource failure and restoration management of ATM networks. We address the issues concerning the provision of the necessary means and functions in order to ensure network performance and availability within acceptable levels under normal and faulty conditions. The proposed system will cover both the control and management planes of the operation of the network, with emphasis on performance, configuration and fault management. Key issues are the intelligent routing, the management of the resources under faulty conditions, and the adequate reservation of resources to be used as spare in the case of link failures. The system will be designed and implemented by adopting the TINA framework and by using a CORBA -based distributed processing environment. The effectiveness of the system will be assessed and demonstrated through field trials based on the National Hosts infrastructure in Europe and Japan.

Activity Leader: Costas Courcoubetis Tel: +30 81 391724 Email: courcou@ics.forth.gr

ICS-FORTH Telecommunications and Networks Laboratory
Last updated Mon May 19 16:12:41 EET DST 1997