Chapter 21 Network Basics for Digital Investigators ©2011 Eoghan Casey. Published by Elsevier Inc. All rights reserved.

Figure 1.1 Copyright © 2011 Academic Press Inc.©2011 Eoghan Casey. Published by Elsevier Inc. All rights reserved. FIGURE 21.1 Map of ARPANET.

Figure 1.1 Copyright © 2011 Academic Press Inc.©2011 Eoghan Casey. Published by Elsevier Inc. All rights reserved. FIGURE 21.2 Timeline of key events.

Figure 1.1 Copyright © 2011 Academic Press Inc.©2011 Eoghan Casey. Published by Elsevier Inc. All rights reserved. FIGURE 21.3 Depiction of hosts with NICs connected to a router to form a network.

Figure 1.1 Copyright © 2011 Academic Press Inc.©2011 Eoghan Casey. Published by Elsevier Inc. All rights reserved. FIGURE 21.4 Hosts connected to a central hub (star typology).

Figure 1.1 Copyright © 2011 Academic Press Inc.©2011 Eoghan Casey. Published by Elsevier Inc. All rights reserved. FIGURE 21.5 Normal FDDI communication versus backup communication when a host is down (double-ring typology).

Figure 1.1 Copyright © 2011 Academic Press Inc.©2011 Eoghan Casey. Published by Elsevier Inc. All rights reserved. FIGURE 21.6 Wireless IEEE network with a PDA and PC connected to an AP. Also shown is the AP connected to the Internet.

Figure 1.1 Copyright © 2011 Academic Press Inc.©2011 Eoghan Casey. Published by Elsevier Inc. All rights reserved. FIGURE 21.7 Dissimilar networks connected using a common language to form an internet.

Figure 1.1 Copyright © 2011 Academic Press Inc.©2011 Eoghan Casey. Published by Elsevier Inc. All rights reserved. FIGURE 21.8 Barbara the Bookie’s Network.

Figure 1.1 Copyright © 2011 Academic Press Inc.©2011 Eoghan Casey. Published by Elsevier Inc. All rights reserved. FIGURE 21.9 Conceptual depiction of TCP/IP with arrows indicating communication between modules.

Figure 1.1 Copyright © 2011 Academic Press Inc.©2011 Eoghan Casey. Published by Elsevier Inc. All rights reserved. FIGURE A simplified depiction of the Open System Interconnection layers showing where TCP/IP fits.

Figure 1.1 Copyright © 2011 Academic Press Inc.©2011 Eoghan Casey. Published by Elsevier Inc. All rights reserved. FIGURE A conceptual representation of packets in network traffic relating to a single flow being extracted and reconstituted to obtain the data they carry (Casey, 2004).

Figure 1.1 Copyright © 2011 Academic Press Inc.©2011 Eoghan Casey. Published by Elsevier Inc. All rights reserved. FIGURE Graphical synopsis of the OSI reference model.

Figure 1.1 Copyright © 2011 Academic Press Inc.©2011 Eoghan Casey. Published by Elsevier Inc. All rights reserved. FIGURE How a Web browser accesses the Internet as seen through the OSI model.

Figure 1.1 Copyright © 2011 Academic Press Inc.©2011 Eoghan Casey. Published by Elsevier Inc. All rights reserved. FIGURE NetIntercept ( showing components of a Web page both in OSI layers and content recovered from network traffic.