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1.3.3.3 Lab - Mapping the Internet - ILM
english
Jakarta Global University
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Lab - Mapping the Internet (Instructor Version)
Instructor Note: Red font color or Gray highlights indicate text that appears in the instructor copy only.
Objectives
Part 1: Test Network Connectivity Using Ping Part 2: Trace a Route to a Remote Server Using Windows Tracert Part 3: Trace a Route to a Remote Server Using Web-Based and Software Tools Part 4: Compare Traceroute Results
Background
Route tracing computer software is a utility that lists the networks data has to traverse from the user's originating end device to a distant destination network. This network tool is typically executed at the command line as: tracert <destination network name or end device address> (Microsoft Windows systems) or traceroute <destination network name or end device address> (Unix and similar systems) Route tracing utilities allow a user to determine the path or routes as well as the delay across an IP network. Several tools exist to perform this function. The traceroute (or tracert) tool is often used for network troubleshooting. By showing a list of routers traversed, it allows the user to identify the path taken to reach a particular destination on the network or across internetworks. Each router represents a point where one network connects to another network and through which the data packet was forwarded. The number of routers is known as the number of "hops" the data traveled from source to destination. The displayed list can help identify data flow problems when trying to access a service such as a website. It can also be useful when performing tasks such as downloading data. If there are multiple websites (mirrors) available for the same data file, one can trace each mirror to get a good idea of which mirror would be the fastest to use. Two trace routes between the same source and destination conducted some time apart may produce different results. This is due to the "meshed" nature of the interconnected networks that comprise the Internet and the Internet Protocols ability to select different pathways over which to send packets. Command-line-based route tracing tools are usually embedded with the operating system of the end device. Other tools, such as VisualRoute™, are proprietary programs that provide extra information. VisualRoute uses available online information to graphically display the route. This lab assumes the installation of VisualRoute. If the computer you are using does not have VisualRoute installed, you can download the program using the following link: visualroute/download.html If you have any trouble downloading or installing VisualRoute, ask your instructor for assistance. Ensure that you download the Lite Edition.
Scenario
Using an Internet connection, you will use three route tracing utilities to examine the Internet pathway to destination networks. This activity should be performed on a computer that has Internet access and access to the command line. First, you will use the Windows embedded tracert utility. Second, you will use a web-based traceroute tool (subnetonline/pages/network-tools/online-traceroute.php). Finally, you will use the VisualRoute traceroute program. Instructor Note: Many schools do not have access to the command prompt. Traceroutes are included in Appendix A for your use. Depending on the situation, this lab can be assigned in the classroom, as homework or can be performed by the instructor as a walk-through demonstration. Free software programs like VisualRoute can quickly go out of date. If VisualRoute Lite Edition is no longer available when you are using this lab, type into your favorite search engine, “download visual traceroute tool”. Some institutions disable ICMP echo replies used by both ping and traceroute utilities. Before students begin this activity, make sure there are no local restrictions related to ICMP datagrams. This activity assumes that ICMP datagrams are not restricted by any local security policy.
Required Resources
1 PC (Windows 7, Vista, or XP with Internet access)
Part 1: Test Network Connectivity Using Ping
Step 1: Determine whether the remote server is reachable.
To trace the route to a distant network, the PC used must have a working connection to the Internet. a. The first tool we will use is ping. Ping is a tool used to test whether a host is reachable. Packets of information are sent to the remote host with instructions to reply. Your local PC measures whether a response is received to each packet, and how long it takes for those packets to cross the network. The name ping comes from active sonar technology in which a pulse of sound is sent underwater and bounced off of terrain or other ships. b. From your PC, click the Windows Start icon, type cmd in the Search programs and files box, and then press Enter.
For Australia: C:&gt; ping apnic
For Europe: C:&gt; ping ripe
For South America: C:&gt; ping lacnic
All these pings were run from a computer located in the U. What happens to the average ping time in milliseconds when data is traveling within the same continent (North America) as compared to data from North America traveling to different continents?
Answer varies based on location. In the data above, the average ping time in milliseconds dramatically increases. What is interesting about the pings that were sent to the European website?
At the time that these pings were sent, the site was unreachable.
Part 2: Trace a Route to a Remote Server Using Tracert
Step 1: Determine what route across the Internet traffic takes to the remote server.
Now that basic reachability has been verified by using the ping tool, it is helpful to look more closely at each network segment that is crossed. To do this, the tracert tool will be used. a. At the command-line prompt, type tracert cisco.
In the example output shown above, the tracert packets travel from the source PC to the local router default gateway (hop 1: 192.168.1) to the ISPs Point of Presence (POP) router (hop 2: 10.18.20). Every ISP has numerous POP routers. These POP routers are at the edge of the ISP’s network and are the means by which customers connect to the Internet. The packets travel along the Verizon network for two hops and then jump to a router that belongs to alter. This could mean that the packets have traveled to another ISP. This is significant because sometimes there is packet loss in the transition between ISPs, or sometimes one ISP is slower than another. How could we determine if alter is another ISP or the same ISP?
e. There is an Internet tool known as whois. The whois tool allows us to determine who owns a domain name. A web-based whois tool is found at whois.domaintools/. This domain is also owned by Verizon according to the web-based whois tool.
To summarize, Internet traffic starts at a home PC and travels through the home router (hop 1). It then connects to the ISP and travels through its network (hops 2-7) until it arrives at the remote server (hop 8). This is a relatively unusual example in which there is only one ISP involved from start to finish. It is typical to have two or more ISP involved as displayed in the following examples.
f. Now examine an example that involves Internet traffic crossing multiple ISPs. Below is the tracert for afrinic:
What happens at hop 7? Is level3 the same ISP as hops 2-6, or a different ISP? Use the whois tool to answer this question.
The Internet traffic goes from being on alter to level3. The whois tool reveals that this is a separate company/separate ISP. What happens in hop 10 to the amount of time it takes for a packet to travel between Washington D. and Paris, as compared with the earlier hops 1-9?
In hops 1-9 most packets traverse their link in 50 ms or less. On the Washington D. to Paris link, the time increases to 132 ms. What happens in hop 18? Do a whois lookup on 168.209.201 using the whois tool. Who owns this network?
TracePath Output:
1: pera.subnetonline (141.138.203) 0 pmtu 1500 1: gw-v130.xl-is (141.138.203) 1 2: rt-eu01-v2.xl-is (79.170.92) 0 3: akamai.telecity4.nl-ix (193.239.116) 1
afrinic: TracePath Output:
1: pera.subnetonline (141.138.203) 0 pmtu 1500 1: gw-v130.xl-is (141.138.203) 0 2: rt-eu01-v2.xl-is (79.170.92) 0 3: xl-internetservices.nikhef.openpeering (217.170.0) 10 4: r22.amstnl02.nl.bb.gin.ntt (195.69.144) asymm 5 4 5: ae-5.r23.londen03.uk.bb.gin.ntt (129.250.5) 49 6: ae-2.r02.londen03.uk.bb.gin.ntt (129.250.5) asymm 7 8 7: dimensiondata-0.r02.londen03.uk.bb.gin.ntt (83.231.235) 18 8: 168.209.201 (168.209.201) 196 9: csw4-pkl-gi1-1.ip.isnet (196.26.0) asymm 10 186 10: 196.37.155 (196.37.155) 185 11: fa1-0-1.ar02.jnb.afrinic (196.216.3) 197
How is the traceroute different when going to cisco from the command prompt (see Part 1) rather than from the online website? (Your results may vary depending upon where you are located geographically, and which ISP is providing connectivity to your school.)
The tracert from the command prompt in Part 1 ended up at a server in Cambridge, Massachusetts. The traceroute from the website in the Netherlands went to a mirror server in the Netherlands. The domain cisco is hosted on many websites or mirrors throughout the world. This is done so that access time to the site will be fast from anywhere in the world.
Compare the tracert from Part 1 that goes to Africa with the tracert that goes to Africa from the web interface. What difference do you notice?
The route across Europe is on a different ISP. Make the point with students that there is not a single backbone to the Internet. Rather there are many backbones to the Internet. They all connect at Peering Points. Performance on the network on one ISP could be very different than performance on the network with a different ISP.
Some of the traceroutes have the abbreviation asymm in them. Any guesses as to what this means? What is its significance?
This is an abbreviation for asymmetric. It means that the test packet took one path to reach the destination, and a different path to return by. Imagine someone driving from their home to New York City. On the way to New York City, they noticed that the highway was congested and traffic was slow. They might decide to come home by a different or asymmetric path.
Step 2: Use VisualRoute Lite Edition
VisualRoute is a proprietary traceroute program that can display the tracing path results graphically. a. Please download the VisualRoute Lite Edition from the following link if it is not already installed: visualroute/download.html If you have any trouble downloading or installing VisualRoute, ask your instructor for assistance. Ensure that you download the Lite Edition. b. Using VisualRoute 2010 Lite Edition, trace the routes to cisco. c. Record the IP addresses in the path in Notepad.
Part 4: Compare Traceroute Results
Compare the traceroute results to cisco from Parts 2 and 3.
Step 1: List the path to cisco using tracert.
192.168.1 > 10.18.20 > 130.81.196 > 130.81.22 > 152.63.1 > 152.63.17 > 152.63.21 >
23.1.
Tracing route to afrinic [196.216.2] over a maximum of 30 hops:
1 1 ms <1 ms <1 ms dslrouter.westell [192.168.1] 2 39 ms 38 ms 37 ms 10.18. 3 40 ms 38 ms 39 ms G4-0-0-2204.ALBYNY-LCR-02.verizon-gni [130.81.197] 4 44 ms 43 ms 43 ms so-5-1-1-0.NY325-BB-RTR2.verizon-gni [130.81.22] 5 43 ms 43 ms 42 ms 0.so-4-0-0.XT2.NYC4.ALTER [152.63.9] 6 43 ms 71 ms 43 ms 0.ae4.BR3.NYC4.ALTER [152.63.16] 7 47 ms 47 ms 47 ms te-7-3-0.edge2.NewYork2.level3 [4.68.111] 8 43 ms 55 ms 43 ms vlan51.ebr1.NewYork2.Level3 [4.69.138] 9 52 ms 51 ms 51 ms ae-3-3.ebr2.Washington1.Level3 [4.69.132] 10 130 ms 132 ms 132 ms ae-42-42.ebr2.Paris1.Level3 [4.69.137] 11 139 ms 145 ms 140 ms ae-46-46.ebr1.Frankfurt1.Level3 [4.69.143] 12 148 ms 140 ms 152 ms ae-91-91.csw4.Frankfurt1.Level3 [4.69.140] 13 144 ms 144 ms 146 ms ae-92-92.ebr2.Frankfurt1.Level3 [4.69.140] 14 151 ms 150 ms 150 ms ae-23-23.ebr2.London1.Level3 [4.69.148] 15 150 ms 150 ms 150 ms ae-58-223.csw2.London1.Level3 [4.69.153] 16 156 ms 156 ms 156 ms ae-227-3603.edge3.London1.Level3 [4.69.166] 17 157 ms 159 ms 160 ms 195.50. 18 353 ms 340 ms 341 ms 168.209. 19 333 ms 333 ms 332 ms csw4-pkl-gi1-1.ip.isnet [196.26.0] 20 331 ms 331 ms 331 ms 196.37. 21 318 ms 316 ms 318 ms fa1-0-1.ar02.jnb.afrinic [196.216.3] 22 332 ms 334 ms 332 ms 196.216.
Trace complete.
C:&gt; tracert lacnic
Tracing route to lacnic [200.3.14] over a maximum of 30 hops:
1 <1 ms <1 ms <1 ms dslrouter.westell [192.168.1] 2 38 ms 37 ms 37 ms 10.18. 3 37 ms 38 ms 40 ms G3-0-9-2204.ALBYNY-LCR-02.verizon-gni [130.81.196] 4 43 ms 42 ms 43 ms so-5-1-1-0.NY325-BB-RTR2.verizon-gni [130.81.22] 5 46 ms 75 ms 46 ms 0.ae2.BR3.NYC4.ALTER [152.63.16] 6 43 ms 43 ms 43 ms 204.255. 7 178 ms 182 ms 178 ms ge-1-1-0.100.gw1.gc.registro [159.63.48] 8 172 ms 180 ms 182 ms xe-5-0-1-0.core1.gc.registro [200.160.0]
9 177 ms 172 ms 181 ms xe-4-0-0-0.core2.nu.registro [200.160.0]
10 173 ms 180 ms 176 ms ae0-0.ar3.nu.registro [200.160.0] 11 184 ms 183 ms 180 ms gw02.lacnic.registro [200.160.0] 12 180 ms 179 ms 180 ms 200.3. 13 182 ms 180 ms 180 ms lacnic [200.3.14]
Trace complete.
1.3.3.3 Lab - Mapping the Internet - ILM
Course: english
University: Jakarta Global University
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