Traffic Management for the Available Bit Rate (ABR) Service in ...
Traffic Management for the Available Bit Rate (ABR) Service in ... Traffic Management for the Available Bit Rate (ABR) Service in ...
Transmitted Cell Rate Link Utilization 180 160 140 120 100 80 60 40 20 TCR for S1 TCR for S2 TCR for S3 0 0 10000 20000 30000 Time in micro-seconds 120 100 (a) Transmitted Cell Rates 80 60 40 20 parking.u 150 0.90 0.90 37 Link Utilization of Sw1-Sw2 link Link utilization of Sw2-Sw3 link 0 0 5000 10000 15000 20000 25000 30000 Time in micro-seconds (c) Link Utilization Queue Length 500 450 400 350 300 250 200 150 100 50 Cells in Q to Sw1-Sw2 link 0 0 10000 20000 30000 Time in micro-seconds (b) Queue Lengths Figure 5.18: Simulation results for the parking lot con guration 131
Figure 5.19: Network con guration with upstream bottleneck. 5.7 Results with Packet Train Workload The most commonly used tra c pattern in congestion simulations is the so called "in nite source model." In this model, all sources have cells to send at all times. It is a good starting con guration because, after all, we are comparing schemes for overload and if a scheme does not work for in nite source it is not a good congestion scheme. In other words, satisfactory operation with in nite source model is necessary. However, it is not su cient. We have found that many schemes work for in nite source models but fail to operate satisfactorily if the sources are bursty, which is usually the case. In developing the OSU scheme, we used a packet train model to simulate bursty tra c [47]. A packet train is basically a \burst" of k cells (probably consisting of segments of an application PDU) sent instantaneously by the host system to the adapter. In real systems, the burst is transfered to the adapter at the system bus rate which is very high and so simulating instantaneous transfers is justi ed. The adapter outputs all its cells at the link rate or at the rate speci ed by the network in case of rate feedback schemes. If the bursts are far apart, the resulting tra c on the link will look like trains of packets with a gap between trains. 132
- Page 107 and 108: 4.10 DMRCA scheme The Dynamic Max R
- Page 109 and 110: on its CCR. Further MAX times out i
- Page 111 and 112: other words, a di erent set of para
- Page 113 and 114: A combination of several ideas in a
- Page 115 and 116: 4.13 SP-EPRCA scheme The SP-EPRCA s
- Page 117 and 118: RTD and shuts o the source (for sta
- Page 119 and 120: 4.14.1 Common Drawbacks Though the
- Page 121 and 122: The ATM Tra c Management standard a
- Page 123 and 124: 5.1.1 Control-Cell Format The contr
- Page 125 and 126: The last two elds are used in the b
- Page 127 and 128: Figure 5.3: Flow chart for updating
- Page 129 and 130: LAF in cell Max(LAF in cell, z) The
- Page 131 and 132: the time of departure (instant mark
- Page 133 and 134: the steady state. The system operat
- Page 135 and 136: 5.2.3 Use Measured Rather Than Decl
- Page 137 and 138: said about the maximum queue length
- Page 139 and 140: The key problem with some unipolar
- Page 141 and 142: Figure 5.6: Space time diagram show
- Page 143 and 144: As noted, these heuristics do not g
- Page 145 and 146: Transmitted Cell Rate ABR Queue Len
- Page 147 and 148: 4. The RM cell contains a timestamp
- Page 149 and 150: 1. The source o ered average cell r
- Page 151 and 152: Transmitted Cell Rate Link Utilizat
- Page 153 and 154: Transmitted Cell Rate Link Utilizat
- Page 155 and 156: Transmitted Cell Rate Link Utilizat
- Page 157: Figure 5.17: The parking lot fairne
- Page 161 and 162: Transmitted Cell Rate Link Utilizat
- Page 163 and 164: Transmitted Cell Rate Link Utilizat
- Page 165 and 166: 5.8 Proof: Fairness Algorithm Impro
- Page 167 and 168: Region 2: y s and x s and U(1 + ) x
- Page 169 and 170: eing divided into eight non-overlap
- Page 171 and 172: Proof for Region 2 Triangular regio
- Page 173 and 174: have: and y 0 = y(1 ; ) z x + y 0 =
- Page 175 and 176: The OSU scheme is, therefore, incom
- Page 177 and 178: workloads, where input load and cap
- Page 179 and 180: (a) Regions used to prove Claim C1
- Page 181 and 182: 6.1 The Basic ERICA Algorithm The s
- Page 183 and 184: A ow chart of the basic algorithm i
- Page 185 and 186: efore competing sources can receive
- Page 187 and 188: that the latest CCR information is
- Page 189 and 190: the CCR value may not be an accurat
- Page 191 and 192: (Target Utilization) (Link Bandwidt
- Page 193 and 194: ABR Capacity Input Rate Overload Fa
- Page 195 and 196: of arithmetic averaging used above.
- Page 197 and 198: level of control. These parameters
- Page 199 and 200: 6.14 ERICA+: Queue Length as a Seco
- Page 201 and 202: 6.16 ERICA+: Maintain a \Pocket" of
- Page 203 and 204: hence, introduces a new parameter,
- Page 205 and 206: Figure 6.4: Linear functions for ER
- Page 207 and 208: and Figure 6.6: The queue control f
Transmitted Cell <strong>Rate</strong><br />
L<strong>in</strong>k Utilization<br />
180<br />
160<br />
140<br />
120<br />
100<br />
80<br />
60<br />
40<br />
20<br />
TCR <strong>for</strong> S1<br />
TCR <strong>for</strong> S2<br />
TCR <strong>for</strong> S3<br />
0<br />
0 10000 20000 30000<br />
Time <strong>in</strong> micro-seconds<br />
120<br />
100<br />
(a) Transmitted Cell <strong>Rate</strong>s<br />
80<br />
60<br />
40<br />
20<br />
park<strong>in</strong>g.u 150 0.90 0.90 37<br />
L<strong>in</strong>k Utilization of Sw1-Sw2 l<strong>in</strong>k<br />
L<strong>in</strong>k utilization of Sw2-Sw3 l<strong>in</strong>k<br />
0<br />
0 5000 10000 15000 20000 25000 30000<br />
Time <strong>in</strong> micro-seconds<br />
(c) L<strong>in</strong>k Utilization<br />
Queue Length<br />
500<br />
450<br />
400<br />
350<br />
300<br />
250<br />
200<br />
150<br />
100<br />
50<br />
Cells <strong>in</strong> Q to Sw1-Sw2 l<strong>in</strong>k<br />
0<br />
0 10000 20000 30000<br />
Time <strong>in</strong> micro-seconds<br />
(b) Queue Lengths<br />
Figure 5.18: Simulation results <strong>for</strong> <strong>the</strong> park<strong>in</strong>g lot con guration<br />
131
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