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

RTT(ms) Feedback Max Q Thoughput
Delay (ms) size(cells)
15 0.01 709 113.37
15 1 3193 112.87
15 10 17833 109.86
30 0.01 719 105.94
30 1 2928 106.9
30 10 15073 107.13
550 0.01 2059 NA
550 1 15307 NA
550 10 17309 NA
Table 8.5: E ect of Feedback Delay
8.15.5 TCP Performance over ATM Backbone Networks
The ATM source bu er requirement isderived by examining the maximum queues
at the source when TCP runs over ABR. We also study the performance when suf-
cient bu ers are not provided and discuss the implications for ATM backbone net-
works.
Source End System Queues in ABR
Table 8.6 shows the results with a 15-source con guration with link lengths of
1000 km (there is no VBR background). The link lengths yield a round trip time
(propagation) of 30 ms and a feedback delay of10ms. We vary the size of the source
end system bu ers from 100 cells to 100000 cells per VC (second column). These
values are compared to the maximum receiver window size (indicated as \Win" in
the table) which is 1024 kB = 24576 cells. The switch has in nite bu ers and uses
299