a simple network simulator

A company with 4 different working units situated at different places as Unit1, Unit2, Unit3 and Unit4. The links of these units are managed as follows Link 1 connects Unit 1 to 2, Link 2 connects Unit 1 to 3 Link 3 connects Unit 2 to 4 Link 4 connects Unit 3 to 4 Links 5 and possibly 6 connect the Gateway Node to the network. The distance between every unit is 400metres where the LAN based solution is deployed using Ethernet. ## Deliverables You need to solve these two problems Problem 1::: Develop * A high quality video link between the unit 1 and Unit 2 (vid1 in both directions) * A medium quality video link from the unit 3 to unit 1 (vid2) At this time a video links fall into these categories. Video phone 64K very low quality Medium quality 6*64Kbps (less than VHS) High quality 2.0Mbps broadcast TV quality. * A high-speed file transfer capability from unit 4 to unit3 (ftp1 in one direction only) * A fault tolerant design is required so that communication can be maintained between any two nodes if any single link fails * In your simulation demonstrate how the system recovers from any single link failure * Use the simulator ns2 to complete these tasks Problem 2:: * Upgrade the network design created to solve Problem 1 to provide a Gateway to the Internet * Create a new gateway node to allow access to the Internet, connect the Gateway via one (Link 5 ) or two links (Links 5 and 6) to the internal network * Assume that a video conference is taking place on the high speed link * Single users at each unit location initiate an FTP download from the Internet via the Gateway Node. * Undertake tests to determine the network design required to ensure that video packets are not lost during FTP download sessions Time when traffic should turn on:: Video conference traffic, turns on at 1.0sec, off at 5 sec ??" vid1 Unit 1 FTP download turns on at 1.1, off 4.1 ??" ftp2 Unit 2 FTP download turns on at 1.2, off 4.2 ??" ftp3 Unit 3 FTP download turns on at 1.3, off 4.3 ??" ftp4 Unit 4 FTP turns download on at 1.4, off 4.4 ??" ftp5 ## Platform Windows xp/2k NS tool (Network simulator)