ENEL 492/ENEL 792 Design of Computer Networks Winter 2021 Lab 1: Introduction to riverbed Modeler Report Chi (Ena) Ho Hmc329 @uregina.ca I. II. OVERVIEW: In this lab, we develop a first-floor basic network of office. Using Riverbed to simulate the network design. Once SCENARIO 1: Create a scenario to simulate and analyze the performance of the ethernet network for office scale with size 100*100m. 1. Context: Initial Topology Create Empty Scenario Network Scale Office Specify the Size 100mx100m Model Family Ethernet Construction of Network Type: Star Network Central Node Model Ethernet_16_hub Node Model Ethernet_wkstn Link model 10Mbps Number 5 The network model: III. RESULT OF SIMULATION: After run simulation, the statistics are collected as below: 1. Ethernet collision count and Utilization (in 10 minutes) 2. Average Ethernet collision count & Utilization (in 10 minutes) 3. Ethernet delay: 4. Average Ethernet Delay: 5. Ethernet Load 6. Average of the server Ethernet load IV. “ADDING TRAFFIC TO THE NETWORK” To simulate the real traffic traces in network, we need to create traffic in Riverbed 1. First, represent users using email, sending file, receiving file and access database: Emails have light size Heavy database Files have light size 2. Second, represent user using IP call (pulse code modulation encode only) We have 2 profiles as below: 3. Set all nodes to support 2 types of profile: 4. Set server to support all services: V. SCENARIO 2: Replace the hub with a switch The simulation model as the image below: The Ethernet delay show as the image below: The average of Ethernet delay: The Ethernet delay when model using switch is quite lower than hub. The reason is pointed that: Hub does not consider to address when it transfers data packet to destination. So, hub will send packet to its all link. Besides, it will not inspect the data packet and it only transfers. In contrast, switch is self-configuration device. It will check address of destination to ensure that the packet will only be sent to the destination. And this characteristic reduces the delay without traffic propagation. VI. SCENARIO 3: Increase the number of nodes to 30 In this scenario, ethernet16_switch is used to be central node. The simulation model as the image below: 1. Ethernet delay: The Ethernet delay of 30 nodes scenario is quite higher than 5 nodes with using the same type of central node (Switch). The number of nodes which connect to the only switch affected to the transfer speed of switch, especially when the various of node requires service from service as the same time VII. ANSWER THE QUESTIONS: 1. What are the 2 questions that you are trying to answer in this simulation and what statistics are going to help you answer these questions? a) The main questions that this simulation trying to answer is: - How does the replacement between the switch and the hub affect to performance of network? - How does the number of node in network affect to performance of network? b) The statistics will help showing the different of performance (load, delay…) to easy compare results between the different scenarios and analysis the cause leading to these results 2. What is the average and peak server load? What is the average network delay? The average server load is the mean of server load in the instant time during the total time of scenario( 10 minutes in the scenario above) For example: - The average server load in this scenario at 2 minutes is 100,000bit/sec The peak server load is the highest value when the network reaches the peak traffic time. In the scenario above, the peak server load is approximate 125,000 bit/sec. - The average network delay is the mean of network delay in the instant time during the total time of scenario( 10 minutes in the scenario above) 3. What is the difference in the average load on the server by adding the new star network? Does this value make sense (look at the ratio of workstations added to the network). What was the change in delay? The network simulation show as the image below: And the average load on the server in 2 scenario (1 star network and 2 star networks) show as the image below: The average load on the server in 1 Star network scenario is much lower than in 2 Star networks This result is reasonable. Because the increase in the number of nodes while there is only one server leads to the increase of load on the server in this case. The Ethernet delay is shown as the image below: The average of Ethernet delay is shown as the image below: As shown in the figure above, the average delay in the 2-star network scenario increases by 0.0001 second from the 2nd to 10th minute compared to the 1-star network scenario. 4. What are the four steps in using the riverbed Modeler? The four steps in using the Riverbed Modeler includes: a) Configuring initial project and scenario b) Building Topology c) Creating Traffic d) Choosing Statistics 5. What is the principal function of the Project Editor? It is the main workspace of project where we can drag, drop or configure each object of project 6. What are the types of Topologies available from the Rapid Configuration Wizard? The topologies in Rapid Configuration including: a) Subnets: It represents the actual LAN network physical constructs which demonstrate the organized form of the network component. b) - Network Objects: Object Palettes: a catalog of different network devices Utility objects: simplify the setup and configuration of network model LAN objects: LAN entities Cloud objects ATM objects Attributes Standard Model - Vendor Models 7. What 3 methods exist to create a Network topology? a) First, Creating a Network topology manually. Add each component to the work space from Object Configuration b) Second, imported from existing scenario or project AppTransaction Xpert file in an existing all the typical parameters of network scenario c) Third, create the topology by choose the construct of network and add all component from Rapid Configuration Wizard. 8. From the results obtained, what is the relationship between the delay, utilization and the number of collisions? From the results obtained, the delay time is proportional to the utilization and the number of collisions. As the image above, we can see that from 4th minute, when the utilization and the number of collision increase, the delay time had the slight increase from 0.00012 to 0.00015 seconds.
