A selective cell discarding scheme using packet-size information

Kenji KIHARA and Toshihisa OZAWA
Electrics and Communications in Japan - Part 1, 81, 11, pp. 48-57 (1998)


In packet communications over an asynchronous transfer mode (ATM) network, if even one cell of a packet is discarded in the network, the entire packet becomes useless. However, other cells of the packet are still transmitted through the network which wastes network resources. This may decrease the packet throughput of users. We propose a selective cell discarding scheme that prevents such useless cells from being transmitted. In this scheme, the behavior of a virtual cell queue is simulated using packet-size information, and a newly arriving packet is accepted only if the length of this virtual queue is greater than or equal to a given threshold. The packet-size information is available when the connectionless network access protocol (CLNAP) and ATM adaptation layer (AAL) type 3/4 are used in the network. Computer simulations have shown that our scheme can prevent decreased packet throughput due to discarded cells, even when the traffic load is very high, and can fairly accept packets regardless of the packet sizes.


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