DOWNLOAD MY Ph.D Thesis - UNAM

More documents

Recommendations

Info

Chapter 5Upstream channel capacity and characterisation pheader) and 18-bytes (Ethernet MAC header/trailer). Therefore, not all of the streamcapacity is available to isochronous applications. For instance, in the worse casescenario when 64-byte packets are delivered, for a 12 kbps isochronous stream theeffective bandwidth (excluding higher layer protocol overhead = 20-bytes TCP + 20-bytes IP + 3-bytes LLC + 18-bytes Ethernet MAC = 61-bytes), is dramatically reducedto 0.56 kbps when the TCP/IP protocol with an Ethernet bridge solution is considered.Such overheads should be taken into account when considering the delivery ofapplications with specific bandwidth requirements. The effective throughput for thedifferent streams as a function of the packet size and protocol stack (see Figure B.1)used for these simulations is given in Table 5.3, (shaded lines in the table present theeffective bandwidth when the TCP/IP with an Ethernet bridge solution is considered,which is the most popular solution in CATV networks).It is evident from Table 5.3, that although lower packet sizes provide quickerinteraction, smaller packet sizes reduce the available bandwidth due to a proportionalincrease in overhead. In order to compensate for the considerable reduction inbandwidth, in the last version of the of the DVB/DAVIC protocol [35] (recentlyTable 5.3 - Effective bandwidth in isochronous streams (kbps).Isochronous Streams (kbps)Packet size (bytes)64 128 256 512 1024 151812 TCP/IP 3.94 7.97 9.98 10.99 11.50 11.66UDP/IP 6.19 9.09 10.55 11.27 11.64 11.75PPP 9.38 10.69 11.34 11.67 11.84 11.89TCP/MAC Eth 0.56 6.28 9.14 10.57 11.29 11.29UDP/MAC Eth 2.81 7.41 9.70 10.85 11.43 11.6132 TCP/IP 10.50 21.25 26.63 29.31 30.66 31.09UDP/IP 16.50 24.25 28.13 30.06 31.03 31.35PPP 25.00 28.50 30.25 31.13 31.56 31.70TCP/MAC Eth 1.50 16.75 24.38 28.19 30.09 30.71UDP/MAC Eth 7.50 19.75 25.88 28.94 30.47 7.5064 TCP/IP 21.00 42.50 53.25 58.63 61.31 62.19UDP/IP 33.00 48.50 56.25 60.13 62.06 62.69PPP 50.00 57.00 60.50 62.25 63.13 63.41TCP/MAC Eth 3.00 33.50 48.75 56.38 60.19 61.43UDP/MAC Eth 15.00 39.50 51.75 57.88 60.94 15.00128 TCP/IP 42.00 85.00 106.50 117.25 122.63 124.37UDP/IP 66.00 97.00 112.50 120.25 124.13 125.39PPP 100.00 114.00 121.00 124.50 126.25 126.82TCP/MAC Eth 6.00 67.00 97.50 112.75 120.38 122.86UDP/MAC Eth 30.00 79.00 103.50 115.75 121.88 30.005-7
Chapter 5Upstream channel capacity and characterisation preleased in October 2001), a new advanced mechanisms is used for header suppression.By using this feature, all constant components of the different headers can besuppressed, thus the effective data rate of isochronous streams (e.g. multiplexed voice,audio and/or video) is remarkably increased.5.3.5 System parameters and assumptionsIn all simulations, one upstream channel with a capacity of 3.088 Mbps and onedownstream channel with 42 Mbps were considered. Another important simulationparameter is the choice of the network size. According to [100] the number of activesubscribers per upstream channel on European cable networks is approximately 50 usersin peak hours of traffic.In our analysis we use cluster sizes of up to 70 stations per upstream channel in order toanalyse the performance of the DVB/DAVIC protocol during high periods ofcongestion. Some scenarios will approach an increased number of stations (up to 340stations), with a reduced traffic load to analyse the maximum number of nodes that canbe supported. The complete set of simulation parameters used in order to produce theresults presented in this chapter are summarised in Table 5.4.Table 5.4 – Simulation parameters.Simulation ParameterValueUpstream data rate (QPSK)3.088 MbpsDownstream rate (64-QAM)42 MbpsDownstream signallingIn BandMaximum number of active NIUs (EuroModems) 340*Minimum and maximum backoff values for the exponential backoff algorithm 3 and 5*Entry spreading factor of the splitting tree algorithm 6*Minimum contention-based slots per signalling frame3 slots*Buffer capacity per NIU3000 ATM cells*Transmission time (cycle) of the signalling frame3 ms*Simulation time for each run60sMaximum reservation request message length32 ATM cells (slots)*Maximum contention access message length0 ATM cells (slots)*Distance from nearest/farthest NIU to the Headend10-16 KmSpacing between closest and farthest NIURandomly distributedHeadend and NIU processing delay2 microseconds eachPropagation delay (coax and fibre)5 microseconds/Km* These parameters will be ranged as indicated by the traffic scenarios5-8
Page 6 and 7:
I would like to thank all the peopl
Page 10:
CHAPTER 6: OPTIMISATIO OF CRA ALGOR
Page 13 and 14:
FIGURE 5.17 - SYSTEM THROUGHPUT VS.
Page 15 and 16:
LIST OF TABLESTABLE 2.1 - NEXT GENE
Page 17 and 18:
Chapter 1Introduction pBecause of h
Page 19 and 20:
Chapter 1Introduction pA first step
Page 21 and 22:
Chapter 1Introduction passumption i
Page 23 and 24:
Chapter 1Introduction ppolynomial b
Page 25 and 26:
Chapter 1Introduction pIn general,
Page 27 and 28:
Chapter 1Introduction pminislots to
Page 29 and 30:
Chapter 1Introduction pThe authors
Page 31 and 32:
Chapter 1Introduction prate access
Page 33 and 34:
Chapter 1Introduction p1.4 Overview
Page 35 and 36:
Chapter 2OVERVIEW OF CURRENT CATVNE
Page 37 and 38:
Chapter 2Overview of current CATV n
Page 39 and 40:
Page 41 and 42:
Page 43 and 44:
Page 45 and 46:
Page 47 and 48:
Page 49 and 50:
Page 51 and 52:
Page 53 and 54:
Page 55 and 56:
Chapter 3THE DVB/DAVIC PROTOCOL3.1
Page 57 and 58:
Chapter 3The DVB/DAVIC protocol pEu
Page 59 and 60: Chapter 3The DVB/DAVIC protocol pMA
Page 61 and 62: Chapter 3The DVB/DAVIC protocol pTh
Page 67 and 68: Chapter 3The DVB/DAVIC protocol p3.
Page 69 and 70: Chapter 4Simulation and analytical
Page 105 and 106: Chapter 5Upstream channel capacity
Page 109: Chapter 5Upstream channel capacity
Page 143 and 144: Chapter 6Optimisation of CRA using
Page 161 and 162:
Chapter 6Optimisation of CRA using
Page 163 and 164:
Page 165 and 166:
Page 167 and 168:
Page 169 and 170:
Page 171 and 172:
Chapter 7PERFORMANCE OPTIMISATION F
Page 173 and 174:
Chapter 7Performance optimisation f
Page 175 and 176:
Page 177 and 178:
Page 179 and 180:
Page 181 and 182:
Page 183 and 184:
Page 185 and 186:
Page 187 and 188:
Page 189 and 190:
Page 191 and 192:
Page 193 and 194:
Page 195 and 196:
Page 197 and 198:
Page 199 and 200:
Page 201 and 202:
aChapter 7Performance optimisation
Page 203 and 204:
Page 205 and 206:
Page 207 and 208:
Page 209 and 210:
Chapter 8Final conclusions p8.2 Gen
Page 211 and 212:
Chapter 8Final conclusions pWe have
Page 213 and 214:
Chapter 8Final conclusions pperform
Page 215 and 216:
Chapter 8Final conclusions pslots i
Page 217 and 218:
Chapter 8Final conclusions pfocused
Page 219 and 220:
Chapter 8Final conclusions preserva
Page 221 and 222:
Chapter 8Final conclusions pbandwid
Page 223 and 224:
Chapter 8Final conclusions pThe opt
Page 225 and 226:
Chapter 8Final conclusions p8.4 Fut
Page 227 and 228:
Chapter 8Final conclusions pApplica
Page 229 and 230:
Chapter 8Final conclusions pTCIS st
Page 231 and 232:
Referencesp[17] I. Cidon, and M. Si
Page 233 and 234:
Referencesp[50] N. F. Huang, C. A.
Page 235 and 236:
Referencesp[85] V. Rangel, R. Edwar
Page 237 and 238:
Referencesp[112] K. Sriram, “Meth
Page 239 and 240:
APPEDIX A: GLOSSARYAALABRADSLATMBCB
Page 241 and 242:
Appendix AGlossary pkbpsLANLLCMACMA
Page 243 and 244:
Appendix AGlossary pUSBUWVDSLVoDVoI
Page 245 and 246:
Appendix BProtocol stack and packet
Page 247 and 248:
Appendix BProtocol stack and packet
Page 249 and 250:
APPENDIX C: D VERIFICATION TEST FOR
Page 251 and 252:
Appendix D Verification test p209 2
Page 253 and 254:
Appendix EResults for a 6 Mbps upst
Page 255:
Appendix FGuide to CD-ROM p IEEE802
show all

DOWNLOAD MY Ph.D Thesis - UNAM

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?