Author: J. Charzinski
Short Description:
The M/D/1-s model, although originally developed for the call level of telephone networks, is a wonderful tool for modeling the effect of randomly arriving equal-length packets (or ATM cells) to a queue, including packet loss rates in finite buffers with space for s packets. However, for two reasons, the M/M/1-s model is not just the same for variable length packets: (1) packets never have negative exponentially distributed sizes, as there are usually minimum and maximum packet sizes. (2) The M/M/1-s model assumes a packet loss if there are s packets in the queue whereas real queues do distinguish the space required for small or large packets, even if the amount of space consumed in the queue may not be strictly proportional to the number of bytes in the packet for memory management reasons.
Keywords:
source modeling
packet size
negative exponential distribution
multi-modal distribution
buffer management
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