Using the Internet seems pretty easy. We go to a web address and up comes a page. Or we go to our favorite social site and see pictures of our friends, families, and pets. But it takes a lot of complex software and hardware to make the Internet seem so simple. The design of the technologies that make today’s Internet work started in the 1960s, and there were over 20 years of research into how to build internetworking technologies before the ﬁrst “Internet” was built in the late 1980s by academics in a project called NSFNet. Since then, the research and development into improving network technologies has continued as networks have become far larger and faster and globally distributed with billions of computers.
In order to better understand how today’s Internet works, we will take a look at how humans and computers have communicated using technology over the years.
1.1 Communicating at a Distance .
1.2 Computers Communicate Differently .
1.3 Early Wide Area Store-and-Forward Networks .
1.4 Packets and Routers .
1.5 Addressing and Packets
1.6 Putting It All Together .
2 Network Architecture
2.1 The Link Layer
2.2 The Internetwork Layer (IP) .
2.3 The Transport Layer (TCP)
2.4 The Application Layer
2.5 Stacking the Layers
3 Link Layer
3.1 Sharing the Air
3.2 Courtesy and Coordination
3.3 Coordination in Other Link Layers
4 Internetworking Layer (IP) 35
4.1 Internet Protocol (IP) Addresses .
4.2 How Routers Determine the Routes .
4.3 When Things Get Worse and Better
4.4 Determining Your Route .
4.5 Getting an IP Address
4.6 A Different Kind of Address Reuse
4.7 Global IP Address Allocation .
5 The Domain Name System
5.1 Allocating Domain Names
5.2 Reading Domain Names .
6 Transport Layer
6.1 Packet Headers .
6.2 Packet Reassembly and Re transmission .
6.3 The Transport Layer In Operation
6.4 Application Clients and Servers
6.5 Server Applications and Ports
7 Application Layer
7.1 Client and Server Applications
7.2 Application Layer Protocols
7.3 Exploring the HTTP Protocol
7.4 The IMAP Protocol for Retrieving Mail
7.5 Flow Control
7.6 Writing Networked Applications 7.
8 Secure Transport Layer 89
8.1 Encrypting and Decrypting Data
8.2 Two Kinds of Secrets
8.3 Secure Sockets Layer (SSL)
8.4 Encrypting Web Browser Trafﬁc
8.5 Certiﬁcates and Certiﬁcate Authorities
9 The OSI Model
9.1 Physical (Layer 1)
9.2 Data Link (Layer 2
9.3 Network (Layer 3) .
9.4 Transport (Layer 4)
9.5 Session (Layer 5)
9.6 Presentation (Layer 6) .
9.7 Application (Layer 7)
9.8 Comparing the OSI and TCP/IP Models .
9.9 Link Layer (TCP/IP) .
9.10Internetwork Layer (TCP/IP) .
9.11Transport Layer (TCP/IP) . .
9.12Application Layer (TCP/IP) .