Chapter 11 Networks of Networks

FIGURE 11.0.F01: Switchboards were the first exchanges. Courtesy of Library of Congress, Prints & Photographs Division, [LC-DIG-ggbain ]

FIGURE 11.0.F02: Point-to-point network: a tin can telephone. Reproduced from Boy’s Book of Science, John Pepper

FIGURE 11.0.F03: Star network. © Holly Kuchera/ShutterStock, Inc.; © 2009fotofriends/ShutterStock, Inc.

FIGURE 11.0.F04: Bus or “party line” network.

FIGURE 11.0.F05: Tree network, or hierarchy.

FIGURE 11.0.F06: A mesh network example.

FIGURE 11.0.F07: Adding a layer to handle internet routing.

FIGURE 11.0.F08: Sending a packet from one LAN to another.

FIGURE 11.0.F09: Control panel of an ARPANET IMP. Photographed by Dr. Richard Smith at the Computer History Museum, California

FIGURE 11.0.F10: Old and new Internet routing structures.

FIGURE 11.0.F11: Address locations in packet headers.

FIGURE 11.0.F12: Dotted decimal notation for Internet addresses.

FIGURE 11.0.F13: Major IP packet fields (IPv4).

FIGURE 11.0.F14: ARP packet contents.

FIGURE 11.0.F15: Command to display the ARP cache.

FIGURE 11.0.F16: Interpreting a network mask.

TABLE 11.0.T01: Scope of addressing information in internet packets

FIGURE 11.0.F17: Reachability depends on address scope.

TABLE 11.0.T02: Layer 2 reachability matrix for Figure 11.17

FIGURE 11.0.F18: Typical low-cost commercial gateway. Courtesy of Dr. Richard Smith

FIGURE 11.0.F19: Layout of the Wireshark window. © Wireshark Foundation

FIGURE 11.0.F20: Ethernet header displayed in Wireshark. © Wireshark Foundation

FIGURE 11.0.F21: ARP Request displayed in Wireshark. © Wireshark Foundation

FIGURE 11.0.F22: ARP Response displayed in Wireshark. © Wireshark Foundation

FIGURE 11.0.F23: IP header displayed in Wireshark. © Wireshark Foundation

FIGURE 11.0.F24: Network gateway display of hosts on the LAN. © Netgear

FIGURE 11.0.F25: Output of a simple nmap command.

FIGURE 11.0.F26: Nmap port listing using the -sV option.

FIGURE 11.0.F27: Nmap of a Windows 7 host.

FIGURE 11.0.F28: Nmap of a Windows 7 host with -PN and -O options.

FIGURE 11.0.F29: Reachability problem.