Traffic Management for the Available Bit Rate (ABR) Service in ...

etransmissions occur at 900 ms and 1900 ms. The merging of the packets at the
AAL5 occurs at 1300 ms. After the second timeout, the window of S2 increases lin-
early from one. Since source S1 does not experience this phenomenon, it gets higher
throughput.
Figure 8.10: Unfairness due to TailDrop
A simple x is what we call Intelligent Tail Drop. This policy sets a threshold a
few cells before the bu er limit. Once the threshold is crossed, the switch drops all
cells except the rst EOM cell. The EOM cell will reach the destination and result in
the dropping of the rst packet and merging of packets is avoided in the destination
AAL5. Whenever any cells are dropped, the switch should ensure that the next EOM
cell is transmitted. This prevents the back-to-back retransmissions and improves
fairness. Since this policy only enhances tail drop, it can still be used in conjunction
with other drop policies like Early Packet Discard (EPD) [75]. A similar policy for
partial packet discard is described in Reference [5]. Drop policies assume importance
for the UBR service class and have been studied in a related work [36].
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