SYSTEM MANAGEMENT IN A FRAME RELAY NETWORK

The introduction of digital transmission systems in wide area networks has resulted in a dramatic improvement in the bit error rate. Fast packet switching is a new switching technique which has been defined in response to this improved error rate. In the spectrum of switching technologies it resides halfway between circuit switching and packet switching and benefits from their respective advantages but suffers none of their disadvantages. Briefly, it is packet switching with minimal functionality in the network, which leads to a corresponding increase in network throughput. Frame relay is the fast packet switching technique proposed for Narrowband Integrated Services Digital Network. Frame relay was originally defined as a bearer service for high speed data only. However, a number of modifications are presented in this thesis which enable it to carry multi-service traffic with differing service requirements. In particular, a classification of traffic is proposed and a buffer architecture and service mechanism are defined to support this classification. In addition, a novel solution to the problem of unacceptable delays incurred by delay sensitive traffic, during the transmission of long low priority frames, is proposed. In fast packet switching, flow control functions are carried out by the end Terminal Equipments, not the network. This makes the network more vulnerable to congestion, and hence a congestion management strategy is required. A critique of the congestion management strategy defined in the frame relay standard is given and the conclusion is reached that the strategy is not compatible with the service requirements of the traffic. An alternative congestion management strategy, called Enhanced Go-back-N is proposed. This is based on an extension of the Go-back-N protocol and simulation results show that, even under extreme overload conditions, it maximises the network throughput. Under the same overload conditions, the congestion strategy proposed in the frame relay standard, exhibits a state of congestion collapse. Further investigations are identified which indicate how frame relay and multi-service networks must develop in the immediate future.

Name dc:type.qualificationname

PhD

Level dc:type.qualificationlevel

Doctoral

Grantor dc:publisher.institution

De Montfort University

Year dc:date.issued

1994

Author dc:creator

• Platt, Amelia

Licence

• https://dora.dmu.ac.uk/bitstreams/9a413950-ce3c-4a63-869b-361906d08f11/download