DOWNLOAD MY Ph.D Thesis - UNAM

More documents

Recommendations

Info

Chapter 8Final conclusions pthe increase in system performance, which can be of up to ≈12% of the maximumchannel capacity.There are however modifications proposed herein, namely modifications at the INAscheduler and the NIU for the support of enhanced reservation request mechanisms. Thepiggyback mechanism and the continuous piggyback have already being integrated inthe third version of the DVB/DAVIC protocol [35] due to their remarkably performanceover the default reservation mechanism (defined in the second version). We stronglyrecommend to cable network operators to buy EuroModems supporting these piggybackmechanisms, here it was proved that the increase in system throughput could be up to25% of the maximum channel capacity for upstream channels supporting Internet andvoice traffic (see Section 7.2.7, Figure 7.8).The unsolicited grant slots (UGS) mechanism, however can achieve a better systemperformance than the piggyback mechanisms in terms of access delays for the supportof CBR traffic, here access delays below 7 ms can be obtained on high traffic loads. Theimplementation of this mechanism requires slight modifications to the INA schedulerand NIU MAC protocol. Here the ‘IA_Capabilities’ field of the Default ConfigurationMessage and the ‘IU_Capabilities’ field of the Sign-on Response Message, contain areserved field (of 5 bits for the) for future implementations, which can be used for thesupport of the UGS mechanism. This functionality requires only one bit, leaving theother four bits for future implementation. This reserved field is of one bit in the lastversion of the DVB/DAVIC standard [35], which can also be used for this functionality.With the UGS mechanism, as stated in Section 7.2.6, the number of slots needed by astation and the periodic intervals can be negotiated during the connection set-up thoughthe use of the ‘Resource Request Message’. This structure is the same as the one usedfor the establishment of fixed-rate connections, with the exception that instead ofassigning slots to a NIU in the fixed-rate region of the signalling frame, these slots areallocated in the reserved access region of the signalling frame, using the ‘ReservationGrant Message’.8-17
Chapter 8Final conclusions p8.4 Future workIn this dissertation we have provided a rigorous performance analysis and introducednovel techniques that increase the network efficiency of the upstream channel.However, there are many interesting issues requiring further research.The latest version of the DVB/DAVIC protocol specification (v.3) [35] has beenrecently released. New features such as header suppression, piggyback mechanisms,connection priority and the performance over a 12 Mbps upstream channel need to beresearched.In this dissertation we have seen that the use of header suppression provides the highestnetwork efficiency. In the latest version, a different approach is used for the suppressionof RTP sessions, which consists of the combination of RTP/UDP/IP headers. Instead ofmaintaining additional state information on all active connections at the headend, so thatthese headers and also the MAC header can be all suppressed (as suggested in [47]),only the fixed fields of the RTP/UDP/IP headers are suppressed in [35], as illustrated inFigure 8.1. This means that only up to 27 bytes (out of 12-bytes RTP + 8-bytes UDP +20-bytes IP = 40 bytes) can be suppressed. An interesting issue here would be to analysethe change in system performance when this strategy is used for the delivery of TCIS.8-18
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 63 and 64:
Page 65 and 66:
Page 67 and 68:
Chapter 3The DVB/DAVIC protocol p3.
Page 69 and 70:
Chapter 4Simulation and analytical
Page 71 and 72:
Page 73 and 74:
Page 75 and 76:
Page 77 and 78:
Page 79 and 80:
Page 81 and 82:
Page 83 and 84:
Page 85 and 86:
Page 87 and 88:
Page 89 and 90:
Page 91 and 92:
Page 93 and 94:
Page 95 and 96:
Page 97 and 98:
Page 99 and 100:
Page 101 and 102:
Page 103 and 104:
Page 105 and 106:
Chapter 5Upstream channel capacity
Page 107 and 108:
Page 109 and 110:
Page 111 and 112:
Page 113 and 114:
Page 115 and 116:
Page 117 and 118:
Page 119 and 120:
Page 121 and 122:
Page 123 and 124:
Page 125 and 126:
Page 127 and 128:
Page 129 and 130:
Page 131 and 132:
Page 133 and 134:
Page 135 and 136:
Page 137 and 138:
Page 139 and 140:
Page 141 and 142:
Page 143 and 144:
Chapter 6Optimisation of CRA using
Page 145 and 146:
Page 147 and 148:
Page 149 and 150:
Page 151 and 152:
Page 153 and 154:
Page 155 and 156:
Page 157 and 158:
Page 159 and 160:
Page 161 and 162:
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 201 and 202: aChapter 7Performance optimisation
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: Chapter 8Final conclusions pThe opt
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

Create successful ePaper yourself

Delete template?

Save as template?