  It is well known that frame aggregation in Internet communications improves
transmission efficiency. However, it also causes a delay that for some
real-time communications is inappropriate, thus creating a trade-off between
efficiency and delay. In this paper, we establish the conditions for frame
aggregation under the IEEE 802.11 DCF protocol to be beneficial on average
delay. To do so, we first describe the transmission time in IEEE 802.11 in a
stochastic framework and then we calculate the optimal value of the frames
that, when aggregated, saves transmission time in the long term. Our findings,
discussed with numerical experimentation, show that frame aggregation reduces
transmission congestion and transmission delays.
