Performance evaluation of buffer management schemes for differentiated services in the internet | |
| Author | Pennatee Rohitsatian |
| Call Number | AIT Thesis no.TC-01-01 |
| Subject(s) | Buffer storage (Computer science) Telecommunication--Traffic |
| Note | A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering, School of Engineering and Technology |
| Publisher | Asian Institute of Technology |
| Series Statement | Thesis ; no. TC-01-01 |
| Abstract | To implement Differentiated Service in the network, Active Queue Management (AQM) can be used. The most widely used AQM is Random Early Detection (RED) scheme. This thesis work focuses on four RED schemes, RED with IN/OUT (RIO-C), Modified RIO scheme (RI+O), Weighted RED (WRED) and RED with IN/OUT Decouple virtual queue (RIO-DC). All schemes use two drop precedences and their dropping thresholds can be set in three ways, Staggered, Partially Overlapped and Overlapped setting. The performance of these schemes is studied in three different traffic cases, Variable Bit Rate (VBR) traffic, Bulk Transfer traffic, such as File Transfer Protocol (FTP) and ON-OFF Pareto and Exponential traffics. In each case, CBR traffic is varied to make the congestion in the bottleneck link and it is always marked as low priority. Another stream can be marked as high priority or low priority depending on the traffic case. By simulation, the performance is considered in terms of packet loss, throughput and mean end-to-end delay. The simulation results show that Staggered model has best performance for all traffic cases. Comparing all RED schemes, RI+O has highest performance even in the heavy congestion period. In terms of the ability to protect VBR traffic from loss, when the burstiness of VBR traffic increases, the performance of RIO-DC scheme is much degraded while the performance of RIO-C, WRED and RI+O is deteriorated slightly. As seen from the simulation results, when the burstiness changes from 2 to 5, the percentage ofVBR packet loss is increased by about 6.5 percent for RIO-DC while it is increased by only 0.5 percent for RIO-C. In bulk transfer case, when profile rate of FTP flow increases, only RI+O scheme can achieve the target rate at the expense of CBR traffic. The comparison of Pareto case and Exponential case shows that heavy-tailed distribution in ON and OFF states of Pareto source can relieve the congestion in the bottleneck link when RIO-C and WRED schemes are implemented. Such a result is shown clearly in WRED scheme. The CBR packet loss in Pareto case is about 5 percent less than in Exponential case and Pareto packet loss is around 1.5 percent less than Exponential packet loss for WRED. |
| Year | 2001 |
| Corresponding Series Added Entry | Asian Institute of Technology. Thesis ; no. TC-01-01 |
| Type | Thesis |
| School | School of Engineering and Technology (SET) |
| Department | Department of Information and Communications Technologies (DICT) |
| Academic Program/FoS | Telecommunications (TC) |
| Chairperson(s) | Erke, Tapio; |
| Examination Committee(s) | Ahmed, Kazi M. ;Teerapat Sanguankotchakom; |
| Scholarship Donor(s) | Telephone Organization of Thailand ; |
| Degree | Thesis (M.Eng.) - Asian Institute of Technology, 2001 |