부산대학교 도서관

In the first phase of the ATM introduction connectionless services constitute a high percentage of the whole traffic. This is due to the great interest in high speed computer interconnection and long distance LAN emulation. This type of traffic in the classical computer networks is served mainly by the TCP transport layer protocol (and the datagram version UDP). These protocols will definitely be applied in the first ATM networks and this is the reason why their performance over ATM is of great importance. Two main possible solutions for serving this type of traffic are proposed by the ATM Forum. The first one, the UBR service carries the traffic in the "best effort" way. The second is the ABR service with the set of preventive mechanisms to avoid congestion in the network. This paper deals with the behaviour of the above protocols over ATM networks using different services as well as presenting some general considerations on how to use these protocols in the broadband networks.