A Revised Gomory-Hu Algorithm Taking Account of Physical Unavailability of Network Channels
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The classical Gomory-Hu algorithm aims for finding, for given input flows, a network topology for data transmission and bandwidth of its channels which are optimized subject to minimal bandwidth criteria. In practice, it may occur that some channels between nodes of the network are not active. Ignoring such channels using the topology obtained be the Gomory-Hu algorithm will not lead to an optimal flow-rate.
In this paper the focus is on a modified algorithm taking into account deficient channels. While the classical algorithm generates a sequence of ring subnets, in our modified version the use of deficient channels is checked at intermediate stages in each cycle of the algorithm. When forming ring subnets, the availability of new channels to be introduced into the ring subnet is checked and in the case of unavailability another ring closest to the optimal one is selected. The network optimized by this modified algorithm guarantees the transmission of the maximum input stream.
KeywordsNetwork topology Channel capacity Gomory-Hu algorithm
(i) This work was realized within the framework of the Jean Monnet 2019 program under Erasmus+’611692-EPP-1-2019-1-UAEPPJMO-MODULE Data Protection in EU’.
It is also to be considered as a first step in a cooperation project under preparation, following up the joint Ukraine-Austria R & D project ‘Traffic and telecommunication networks modelling’, project No. UA 10/2017/0118U001750, M-130/2018 (cf ).
(ii) The authors thank Nadyja Popovuch, student at Lviv Polytechnic National University, for providing figures.
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