Figure 6-1 Growth pattern of Internet hosts MillionMillionMillionMillion

Figure 6-2 The Internet Hierarchy Subscribers ISPs NAPs The Internet Infrastructure HOME Dial-up, DSL, Cable Businesses T-1s ISP POPs T-3s Backbone

Figure 6-3 A Router joining three networks Router Switch Internet

Figure 6-5 Distance Vector vs. Link State Source Destination X Destination unreachable Link State vs Distance Vector Pure Distance Vector A B C D Cost = 5 Cost = 10 Cost = 1 Cost = 3

Figure 6-6 Interior and Exterior Protocols AS300 AS200 AS100 Exterior protocol running here Interior protocol running here AS (Autonomous Systems)

Figure 6-7 The Anatomy of an IPv4 address NNNNHHHH Network Octet First Octet Binary Range values Host E First Octet Decimal range values Host D Network C Host Network B Host A Octet 4 Octet 3 Octet 2 Class Octet = 8 bits N = network portion of the IP address H = host portion of the IP address Class A Class B Class C Class D Class E Examples :

Figure 6-8 Network Address Translation PRIVATE Network PUBLIC Network Internet OUT IN NAT Router LAN A NAT router translates IP addresses coming into and leaving the private network Inside IP address: outside IP address: e-bay Your IP address:

Figure 6-9 A firewall using DMZ Internet DMZ Firewall Router Switch Web server File server server Protected Zone Web server FTP Server server NIC 3 NIC 2 NIC 1

Figure 6-10 Firewalls using Protocol Switching Internet Firewall Router Switch Web server File server server Protected Zone Router Switch Web server File server server IPX/SPX Protected Zone TCP/IP IPX/SPX only Dead zone TCP/IP IPX/SPX only TCP/IP

Chapter 6 Figure 6-1Growth pattern of Internet hosts Figure 6-2The Internet Hierarchy Figure 6-3Router with three networks Figure 6-4Client/Server Relationship Figure 6-5TCP/IP Suite of Protocols Figure 6-6Chat screen Figure 6-7Distance Vector vs. Link State Figure 6-8Interior and Exterior Routing Protocols Figure 6-9Network Address Translation Figure 6-10A home network firewall

Figure 6-4 Client Server Client Server Printer

Figure 6-6 Interior and Exterior Protocols AS 200AS 100 AS 300 Interior Routing Protocol Exterior Routing Protocol AS (Autonomous Systems)