CS 3873 Computer Networks Group Project 1 Due Friday November 4 1 Exploring an IPv4 Network This project uses the testbed available in the main CS Lab. You will need to use linux network commands and Cisco router commands for this project. Please note that access to LINUX machines is via SSH only and access to routers is via TELNET only. Note that you cannot directly access any of these devices, except netgate, from the CS department lab machines; you must log into netgate first. The full domain name of this machine is netgate.cs.utsarr.net. Ignore any IPv6 information you find; this will be used in future projects. Devices that use only IPv6 have been omitted from the diagram, even though you may have these devices show up when you use the show cdp nei command. The networks shown in Figure 1 are available to explore and use for subsequent projects. All routers are Cisco 2600 models with varying number of connections. The known portion of the network consists of three autonomous systems, namely, AS 1, AS 2 and AS 3, each with one router. The 24-bit network prefix for LANS within the domain and the interface address for the routers within the domain uses the following mapping: 10.ASN.Z.0/24, where Z=1,2, etc. Point-to-point links between directly connected routers use this mapping: 10.100.XY.0/30, where X,Y are the routers on the link by router number. Each AS is connected to the network cloud (AS 1) by one or more connections. Some routers are interconnected using Ethernet switches (S1, S2, etc). Note that not all switches in Figure 1 are distinct switches; some may be separate broadcast domains implemented using Virtual LANs (VLANs). 2 Systematic Network Discovery There are many ways to learn about this network since you have access to all of the devices you find. In the interest of learning about this process, you should refrain from using nmap and other such comprehensive scanning and discovery tools when doing this project. The following points should help you approach this task in an organized way. You must discover the network before you can do tasks 1 and 2. • Learn everything about the machine you are using first. This means { how many adapters are installed { which IP address is assigned to each adapter{ which network mask is associated with each adapter { what is the default gateway address { are there any static routes in the routing table { are there any entries in the arp table • Next determine the size of each directly attached network by looking at the network mask for the adapter connecting to each network. This will give you a clue as to how many addresses to probe for a response. • Carefully note the addresses that respond. • Attempt to get a login prompt from each address, remembering that Cisco devices only support TELNET and LINUX workstations only support SSH. • If you gain access to an Ethernet switch { Note any Cisco devices that are neighbors and the ports for these devices { Note any other ports that show the link state is up { Note any VLAN IDs that are defined on any of the ports with the link state • If you gain access to a router { Check on which routing protocols, if any, are running on the router { Note all routes in the routing table { Note the network address and mask for each interface • Repeat these steps until you believe nothing new can be discovered There are no filters or firewalls blocking access to any part of this lab network. Perform the following tasks after your discovery process to get more information about the testbed. 1. Using the iperf tool found on nodes 1,3 and 4, measure the maximum bandwidth of the path between Node 1 and Node 3; repeat for Node 1 and Node 4. 2. Use the show cdp neighbor command on each router and note all the neighboring Cisco devices.3 Project Report Answer the following questions clearly in your report 1. Describe how you discovered the IP addresses of the devices you can directly reach from netgate? Directly reach means access the device without going through an intervening router. 2. Show the iperf configuration for both the client and server needed to measure packet loss. 3. What is the minimum bandwidth between Node 1 and Node 3? What is the RTT? 4. Looking at the routing table in R1, which special route is not being advertised by AS 1? 5. List the ASNs running an intra-AS routing protocol? What intra-AS routing protocol do they use? 6. List the ASNs running an inter-AS routing protocol? What inter-AS routing protocol do they use? 7. Are any routes obtained by an intra-AS protocol that are provided to an inter-AS protocol for further distribution? 8. Is the physical and logical topology the same inside of each AS? If not, provide a diagram that shows the differences. 9. Node RL dual is acting as what kind of network device? 10. What changes would you make to the routing configuration of R3 to force traffic from Node 2 to Node 4 to pass through this router? Submit a hardcopy of your assignment at the beginning of class on the due date.Figure 1