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

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6.22.7 Adaptation to Various Source Tra c Models . . . . . . . . 194 6.22.8 Bursty Tra c . . . . . . . . . . . . . . . . . . . . . . . . . . 195 6.22.9 ACR Retention . . . . . . . . . . . . . . . . . . . . . . . . . 197 6.23 Summary of the ERICA and ERICA+ Schemes . . . . . . . . . . . 198 7. Source Rule Design for the ABR Service . . . . . . . . . . . . . . . . . . 223 7.1 Use-It-or-Lose-It Policies . . . . . . . . . . . . . . . . . . . . . . . . 224 7.1.1 Issues in Use-It-or-Lose-It . . . . . . . . . . . . . . . . . . . 225 7.1.2 Early UILI Proposals . . . . . . . . . . . . . . . . . . . . . 226 7.1.3 Problems and Side E ects of Early Proposals . . . . . . . . 228 7.1.4 Worst Case Performance . . . . . . . . . . . . . . . . . . . . 228 7.1.5 Bursty and RPC Tra c Performance . . . . . . . . . . . . . 229 7.1.6 December 1995 Proposals . . . . . . . . . . . . . . . . . . . 230 7.1.7 Unresolved UILI Issues . . . . . . . . . . . . . . . . . . . . . 230 7.1.8 Count-Based UILI Proposal . . . . . . . . . . . . . . . . . . 231 7.1.9 Time-Based UILI Proposal . . . . . . . . . . . . . . . . . . 237 7.1.10 Joint Source-Based UILI Proposal . . . . . . . . . . . . . . 238 7.1.11 Switch-Based Proposal . . . . . . . . . . . . . . . . . . . . . 239 7.1.12 Simulation Results . . . . . . . . . . . . . . . . . . . . . . . 240 7.1.13 Summary of UILI Alternatives and ATM Forum Decision . 252 7.2 Issues with Low Rate Sources . . . . . . . . . . . . . . . . . . . . . 253 7.3 Summary of Source Rule Design Issues . . . . . . . . . . . . . . . . 255 8. Supporting Internet Applications over the ATM-ABR Service . . . . . . 256 8.1 TCP control mechanisms . . . . . . . . . . . . . . . . . . . . . . . 258 8.2 Closed Loop vs Open Loop Control Revisited . . . . . . . . . . . . 260 8.3 Nature of TCP Tra c at the ATM Layer . . . . . . . . . . . . . . 261 8.4 TCP Performance With Cell Loss . . . . . . . . . . . . . . . . . . . 264 8.5 Source Model and TCP Options . . . . . . . . . . . . . . . . . . . 265 8.6 ABR Source End System and ERICA Parameters . . . . . . . . . . 266 8.7 The n Source + VBR Con guration . . . . . . . . . . . . . . . . . 266 8.8 Performance Metrics . . . . . . . . . . . . . . . . . . . . . . . . . . 268 8.9 Peak TCP Throughput . . . . . . . . . . . . . . . . . . . . . . . . 268 8.10 E ect of Finite Bu ers . . . . . . . . . . . . . . . . . . . . . . . . . 270 8.11 E ect of Finite Bu ers and Varying ABR Capacity . . . . . . . . . 272 8.12 Observations on Tail Drop . . . . . . . . . . . . . . . . . . . . . . . 276 8.13 Summary of TCP/IP performance over ABR under lossy conditions 278 8.14 Bu ering Requirements for TCP over ABR . . . . . . . . . . . . . 279 8.14.1 Assumptions . . . . . . . . . . . . . . . . . . . . . . . . . . 280 8.14.2 Derivation of the bu er requirement . . . . . . . . . . . . . 281 xi
8.15 Factors A ecting Bu ering Requirements of TCP over ATM-ABR Service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 295 8.15.1 E ect of Number of Sources . . . . . . . . . . . . . . . . . . 296 8.15.2 E ect of Round Trip Time (RTT) . . . . . . . . . . . . . . 296 8.15.3 LANs: E ect of Switch Parameters . . . . . . . . . . . . . . 297 8.15.4 E ect of Feedback Delay . . . . . . . . . . . . . . . . . . . . 298 8.15.5 TCP Performance over ATM Backbone Networks . . . . . . 299 8.15.6 Summary of bu ering requirements for TCP over ABR . . . 302 8.16 E ect of ON-OFF VBR Background Tra c . . . . . . . . . . . . . 303 8.16.1 Simulation Results . . . . . . . . . . . . . . . . . . . . . . . 304 8.16.2 Summary of ON-OFF VBR background e ects . . . . . . . 311 8.17 E ect of Long-Range Dependent (LRD) VBR background tra c . 312 8.17.1 Overview of MPEG-2 over ATM . . . . . . . . . . . . . . . 312 8.17.2 VBR Video modeling . . . . . . . . . . . . . . . . . . . . . 317 8.17.3 Modeling MPEG-2 Transport Streams over VBR . . . . . . 318 8.17.4 Observations on the Long-Range Dependent Tra c Generation Technique . . . . . . . . . . . . . . . . . . . . . . . . . 320 8.18 Simulation Con guration and Parameters . . . . . . . . . . . . . . 321 8.18.1 E ect of High Variance and Total VBR Load . . . . . . . . 323 8.18.2 Comparison with ON-OFF VBR Results . . . . . . . . . . . 325 8.18.3 Satellite simulations with Short Feedback Delay . . . . . . . 326 8.18.4 Satellite simulations with Long Feedback Delay . . . . . . . 328 8.18.5 Summary of the e ect of long-range dependent VBR . . . . 330 8.19 E ect of bursty TCP applications . . . . . . . . . . . . . . . . . . . 331 8.20 Summary of TCP over ABR results . . . . . . . . . . . . . . . . . . 333 9. The Virtual Source/Virtual Destination (VS/VD) Feature: Design Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 337 9.1 Switch Queue Structure . . . . . . . . . . . . . . . . . . . . . . . . 339 9.1.1 A Non-VS/VD Switch . . . . . . . . . . . . . . . . . . . . . 339 9.1.2 A VS/VD Switch . . . . . . . . . . . . . . . . . . . . . . . . 340 9.1.3 A VS/VD Switch with Unidirectional Data Flow . . . . . . 342 9.1.4 Bi-directional Data Flow . . . . . . . . . . . . . . . . . . . . 342 9.2 The ERICA Switch Scheme: Renotated . . . . . . . . . . . . . . . 344 9.2.1 Rate Calculations in a non-VS/VD Switch . . . . . . . . . . 344 9.2.2 Rate Calculations in a VS/VD Switch . . . . . . . . . . . . 345 9.3 VS/VD Switch Design Options . . . . . . . . . . . . . . . . . . . . 346 9.3.1 Measuring the VC's Current Rate . . . . . . . . . . . . . . . 346 9.3.2 Measuring the Input Rate at the Switch . . . . . . . . . . . 347 9.3.3 E ect of Link Congestion Actions on Neighboring Links . . 348 9.3.4 Frequency of Updating the Allocated Rate . . . . . . . . . . 349 xii
Page 1 and 2: Tra c Management for the Available
Page 3 and 4: ABSTRACT With the merger of telecom
Page 5 and 6: Tra c Management for the Available
Page 7 and 8: To my family iv
Page 9 and 10: VITA April 30, 1971 :::::::::::::::
Page 11 and 12: 2.7 Switch Behavior . . . . . . . .
Page 13: 5.8 Proof: Fairness Algorithm Impro
Page 17 and 18: Bibliography . . . . . . . . . . .
Page 19 and 20: 8.12 Maximum Queues for Satellite N
Page 21 and 22: 5.1 Transmitted cell rate (instanta
Page 23 and 24: 6.13 Results foratwo sources con gu
Page 25 and 26: 7.11 E ect of UILI on Medium Bursts
Page 27 and 28: C.3 Flow Chart of Bi-Directional Co
Page 29 and 30: header information which limits the
Page 31 and 32: switches since a standard does not
Page 33 and 34: congestion control deals with the c
Page 35 and 36: hand side of the equation is the su
Page 37 and 38: analyses which are used to validate
Page 39 and 40: CHAPTER 2 THE ABR TRAFFIC MANAGEMEN
Page 41 and 42: time (RTT). As we explain later, AB
Page 43 and 44: feedback from nearby switches to re
Page 45 and 46: Note that in-rate and out-of-rate d
Page 47 and 48: Data cells also have an Explicit Fo
Page 49 and 50: opportunity the source may nd that
Page 51 and 52: Figure 2.7: Scheduling of forward R
Page 53 and 54: as the timeout value) which reduces
Page 55 and 56: It has been incorrectly believed th
Page 57 and 58: NI CI Action 0 0 ACR Min(ER, ACR +
Page 59 and 60: Source Rule 13: Sources can optiona
Page 61 and 62: Switch Rule 1: This rule speci es t
Page 63 and 64: Observe that the ABR tra c manageme
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complex method like per-VC queuing
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graphs have a steady state with con
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Figure 3.2: Operating point between
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The following example illustrates t
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mention this concept of fairness fo
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control problem was also simpler. S
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of such an occurrence is expected t
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y giving only one feedback per meas
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CHAPTER 4 SURVEY OF ATM SWITCH CONG
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The adaptive FCVC algorithm [63] co
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np. Thus, long path VCs have fewer
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networks like ATM can have complete
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scheme followed by a discussion of
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exibility of decoupling the enforce
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4.6.1 Key Techniques In EPRCA, the
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If the mean ACR is not a good estim
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is the ratio of the input rate to t
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which shares the link equally as al
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proportional to the the unused ABR
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The key technique in the scheme is
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the bandwidth allocations to satis
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4.10 DMRCA scheme The Dynamic Max R
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on its CCR. Further MAX times out i
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other words, a di erent set of para
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A combination of several ideas in a
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4.13 SP-EPRCA scheme The SP-EPRCA s
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RTD and shuts o the source (for sta
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4.14.1 Common Drawbacks Though the
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The ATM Tra c Management standard a
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5.1.1 Control-Cell Format The contr
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The last two elds are used in the b
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Figure 5.3: Flow chart for updating
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LAF in cell Max(LAF in cell, z) The
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the time of departure (instant mark
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the steady state. The system operat
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5.2.3 Use Measured Rather Than Decl
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said about the maximum queue length
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The key problem with some unipolar
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Figure 5.6: Space time diagram show
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As noted, these heuristics do not g
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Transmitted Cell Rate ABR Queue Len
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4. The RM cell contains a timestamp
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1. The source o ered average cell r
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Transmitted Cell Rate Link Utilizat
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Figure 5.17: The parking lot fairne
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Figure 5.19: Network con guration w
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5.8 Proof: Fairness Algorithm Impro
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Region 2: y s and x s and U(1 + ) x
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eing divided into eight non-overlap
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Proof for Region 2 Triangular regio
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have: and y 0 = y(1 ; ) z x + y 0 =
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The OSU scheme is, therefore, incom
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workloads, where input load and cap
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(a) Regions used to prove Claim C1
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6.1 The Basic ERICA Algorithm The s
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A ow chart of the basic algorithm i
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efore competing sources can receive
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that the latest CCR information is
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the CCR value may not be an accurat
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(Target Utilization) (Link Bandwidt
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ABR Capacity Input Rate Overload Fa
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of arithmetic averaging used above.
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level of control. These parameters
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6.14 ERICA+: Queue Length as a Seco
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6.16 ERICA+: Maintain a \Pocket" of
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hence, introduces a new parameter,
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Figure 6.4: Linear functions for ER
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and Figure 6.6: The queue control f
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small averaging intervals. If the a
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The maximum value of T 0 also depen
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6.22 Performance Evaluation of the
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espectively. The target delay T 0 i
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6.22.4 Fairness Figure 6.9: Parking
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st link, VC 15 is limited to a thro
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From the gures, it is clear that ER
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counts the bursty source as active
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6.23 Summary of the ERICA and ERICA
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(a) Transmitted Cell Rate (c) Link
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(a) Transmitted Cell Rate (basic ER
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Page 241 and 242:
Page 243 and 244:
Page 245 and 246:
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RM cells. In this chapter, we devot
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low. This tradeo was discovered and
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in the speci cation. b) ACR shall n
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7.1.6 December 1995 Proposals There
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Figure 7.2: Multiplicative vsAdditi
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is never triggered. However, the PR
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simulation results of bursty source
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1. The time-based proposal also ind
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The switch maintains a local alloca
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PNI = f0, 1g : f1 ) No rule 5b, 0 )
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after reaching the goal. The time-b
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Figure 7.8: Closed-Loop Bursty Tra
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The algorithm measures the load and
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Medium Bursts Medium bursts are exp
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count-based technique may be insu c
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Figure 7.13: An event trace illustr
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CHAPTER 8 SUPPORTING INTERNET APPLI
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u ering which does not depend upon
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4 make it to the destination are ar
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Figure 8.3: At the ATM layer, the T
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issues and e ect of bursty applicat
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from the loss and they trigger the
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8.8 Performance Metrics We measure
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the performance is fair. Also, the
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Figure 8.7(b) shows the rates (ACRs
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Window Size in bytes vfive-tcp/opti
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The e ect of large bu ers on CLR is
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8.13 Summary of TCP/IP performance
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Feedback delay: Twice the delay fro
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on a link, two cells are expected a
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state only after the switch algorit
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queue length is less susceptible to
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to equalize rates for fairness, and
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QB = Link bandwidth (RT T ; T ) and
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u ered at the end-system, and not i
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Part b): When ABR load goes away, t
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All our simulations presented use t
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Averaging RTT(ms) Feedback Max Q Th
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a modi ed version of the ERICA algo
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ABR is better than UBR in these (en
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problems. During the ON time, the V
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hand, the frequency of the VBR is h
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like ERICA+ which uses the queueing
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minimum fairshare is low. This may
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8.17 E ect of Long-Range Dependent
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terminology) are called \Presentati
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The key point is that the MPEG-2 ra
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the MPEG-2 Transport Stream, and st
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8.17.4 Observations on the Long-Ran
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For the video sources, we choose me
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Video Sources ABR Metrics # Mean St
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However, with modi cations to ERICA
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Video Sources ABR Metrics # Avg Src
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Video Sources ABR Metrics # Avg Src
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On the other hand, if the applicati
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of managing bu ers, queueing, sched
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hence control the total load on the
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call such a switch a \VS/VD switch"
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Figure 9.2: Per-class queues in a n
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which arises is where the rate calc
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9.2 The ERICA Switch Scheme: Renota
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The unknowns in the above equations
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Figure 9.9: Two methods to measure
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9.4 VS/VD Switch Design Options 9.4
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# VC Rate VC Input Rate Input Rate
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8 uses source rate measurement, we
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The allocated rate update and the e
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sources in chapter 6. We expect the
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con guration mentioned in the table
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can be very di erent for di erent V
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CHAPTER 10 IMPLEMENTATION ISSUES At
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With an enhanced UBR service, appli
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2. Some switch schemes have a proce
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4. Large legacy switches have a pro
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section 9. Further, WAN switches wo
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CHAPTER 11 SUMMARY AND FUTURE WORK
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good transient performance. Since r
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variant background tra c conditions
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APPENDIX A SOURCE, DESTINATION AND
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7. After following behaviors #5 and
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set the QL and SN elds to zero, pre
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d) VS/VD Control: The switch may se
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5. Setting of other parameters at V
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4. The averaging interval timer exp
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1. Initialization: Target Cell Rate
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THEN IF (OCR In Cell Fair Share Rat
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APPENDIX C ERICA SWITCH ALGORITHM:
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Number Active VCs In Last Interval
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IF (NOT(Averaging VCs Option)) THEN
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IF (Load Factor = In nity) THEN Loa
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; (Contribution[VC] = Decay Factor)
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Name Explanation Flow Chart (FC) or
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Figure C.2: Flow Chart for Achievin
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Figure C.4: Flow Chart of averaging
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Figure C.6: Flow chart of averaging
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C.3 Pseudocode for VS/VD Design Opt
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(* | Bottleneck rate of next loop |
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Follow SESRules 1-4 (see appendix A
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CRM - Missing RM-cell Count DIR bit
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TUB -Target Utilization Band Trm -
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[12] J. Bennett and G. Tom Des Jard
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[38] M. Grossglauser, S.Keshav, and
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[64] H. T. Kung. Flow Controlled Vi
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