To avoid overload of links, as well as packet loss in the network uses the coordination method. This method is based on the possibility of converting the original minimization problem in a simpler maximization problem and the solution of this problem using a two-level iterative computational structure. In this paper the analysis of convergence of the two-level hierarchical routing method with coordination is given.
Lemeshko O., Nevzorova O., Hailan A. The Increasing Convergence of Coordination Procedure in The Implementation of Multipath Hierarchical Routing // Proceedings of First International IEEE Conference «Problems of Infocommunications. Science and Technology» (PICS&T-2014). – Kharkiv, Ukraine: 14-17 October, 2014. – PP. 45-48.

The flow-based model of multicast routing in the telecommunications network is developed. The model is represented by a system of linear algebraic inequalities and equations of the network state. Model calculates a set of paths for multicast routing with a maximum bandwidth or a minimum number of hops. The model includes conditions to prevent a possible overload of network links.
Lemeshko, O.V. ; Arous, Kinan Mohamad. The flow-based model of multicast routing // Microwave and Telecommunication Technology (CriMiCo), 2013 23rd International Crimean Conference. - PP. 523-524.

A Design of flow-based model for MPLS Fast ReRoute is proposed in the paper. The model allows calculating two types of paths, i.e. primary and backup ones, for the same flow. Depending on the parameters of the model, different schemes of reservation such as link protection, node protection, or path protection, can be implemented. In the course of solving the problem of MPLS Fast Reroute the classical metric of primary and backup paths is minimized. The nonlinear restrictions, which are responsible for prevention of node, link or path intersection of primary and backup routes, are introduced in the structure of the model.
Lemeshko, O.V. ; Kozlova, H.V. ; Romanyuk, A.A. Flow-based model of fault-tolerant routing in MPLS-network // Microwave and Telecommunication Technology (CriMiCo), 2013 23rd International Crimean Conference. - PP. 509 - 510.

Flow model for multipath routing with guaranteed the quality of service (QoS) is proposed. The model is based on the updated version of flow conservation law, which is taking into account the possible packet loss caused by buffer overflow at the network routers. The accounting such losses is related to revise conditions associated with the quality of service. By using tensor approach analytical boundary conditions were obtained. The conditions allow ensuring different parameters of the quality of service (rate, average delay and packet loss probability) at the same time. In addition, proposed model provides minimal value of average end-to-end packet delay where delays along all paths are same. As a result jitter caused by the multipath routing (difference between delays along different paths) is minimized. The developed conditions for QoS ensuring have invariant form which do not depend on the used at the interface. Changing the traffic models and/or packet servicing algorithm is related to a modification of the metric only within the same form of conditions.
Lemeshko O.V., Yevseyeva O.Yu., Garkusha S.V. A Tensor Model of Multipath Routing Based on Multiple QoS Metrics // 2013 International Siberian Conference on Control and Communications (SIBCON). Proceedings. – Krasnoyarsk: Siberian Federal University. Russia, Krasnoyarsk, September 12−13, 2013. IEEE Catalog Number: CFP13794-CDR. - P. 1-4.

In this paper the mathematical model and two-level hierarchical method of routing jointly with resources reservation in IP/IntServ network are given.
Lemeshko A., Ahmad M. Hailan, Yevsyeyeva O. Mathematical Model and Method of Routing with Resources Reservation in IP/IntServ Network // Modern Problems of Radio Engineering, Telecommunications and Computer Science. Proceedings of the international Conference TCSET’2012. – Lviv-Slavske, Ukraine, February 21-24, 2012: Publishing House of Lviv Polytechnic, 2012. – P. 325-326.

In this paper an approach to the flow-based modeling of two-level routing in multiservice networks is considered. The model supports the source routing. At the low level - the level of edge routers - the routes are directly computed, and at the top level the received decisions are coordinated for excluding overloads of communication channels in a multiservice network.
Lemeshko O., Ahmad M. Hailan, Ali S. Ali. A flow-based model of two-level routing in multiservice network // Modern Problems of Radio Engineering, Telecommunications and Computer Science. Proceedings of the international Conference TCSET’2010. – Lviv-Slavsko: Publishing House of Lviv Polytechnic, 2010. – P. 225.

In the paper the mathematical model of traffic management in the MPLS-TE DiffServ network is proposed. This model describes the processes of routing and distribution channel resource. In article the method of two-level traffic management in the MPLS-TE DiffServ network is offered to improve the scalability of the solutions on the basis of interactions prediction.
Lemeshko O.V., Ahmad M. Hailan, Starkova O.V. Multi-level traffic management in the MPLS-TE DiffServ network // 11-th International Conference THE EXPERIENCE OF DESIGNING AND APPLICATION OF CAD SYSTEMS IN MICROELECTRONICS Polyana-Svalyava-(Zakarpattya), UKRAINE 23 - 25 February 2011: Publishing House of Lviv Polytechnic, 2011. – P. 118-120.