Congestion Control Scheme Based on Traffic Priority in Computer Networks with Finite Nodal Buffer


IEICE TRANSACTIONS (1976-1990)   Vol.E67   No.5   pp.279-286
Publication Date: 1984/05/25
Online ISSN: 
Print ISSN: 0000-0000
Type of Manuscript: PAPER
Category: Computer Communication

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Store-and-forward communication networks with no effective means of flow control are subject to congestion under heavy load conditions. In this paper a distributed congestion control policy, called PF-C, with nodal buffer management strategy based on traffic priorities is proposed and analyzed. The priority of a packet is depended upon the number of hops it has traveled and the number ob hops it has to travel to reach its destination. More importantly, packets are identified into classes according to their priorities. The limited number of buffers (limit value) at any node to be occupied by each class of packets are assigned. The mechanism of this policy is that, a packet which arrived at a given node is rejected if the total number of allocated buffers exceeds a limit value corresponding to its class. Rejected packets are dropped from the network and considered as lost. This policy is analyzed in the context of symmetrical networks, whereby a queuing model is developed. Finally, network throughput which is an example of system performance, is formulated in terms of offered load, total number of buffers in a node and the limit values. Numerical applications to loop networks clearly demonstrate the good behavior of this policy to achieve the maximum network throughput.