CS402: Computer Communications and Networks

5.2: Internet Protocol

• Université Catholique de Louvain: Olivier Bonaventure's "Computer Networking: Principles, Protocols, and Practice" URL

  Read the introduction to section 5.2, "Internet Protocol." Stop at section 5.2.1 "IP Version 4," which you will read below.

  In this section we will explore the Internet Protocol (IP) to discover how IP enables the applications running above the transport layer (UDP/TCP) to utilize any of the different datalink layers available.

• 5.2.1: IP version 4 (IPv4)

  • Université Catholique de Louvain: Olivier Bonaventure's "Computer Networking: Principles, Protocols, and Practice" URL

    Read section 5.2.1, "IP version 4," on pages 141-150.

    This section starts with a discussion of IP version 4 before exploring network addressing in more detail. As you read, consider the following questions: What are two of the problems with IP version 4 that led to the development of the Classless Interdomain Routing (CIDR) architecture? How does CIDR improve the scalability of the IP routing system?

• 5.2.2: Internet Control Message Protocol (ICMP) Version 4

  • Université Catholique de Louvain: Olivier Bonaventure's "Computer Networking: Principles, Protocols, and Practice" URL

    Read section 5.2.2, "ICMP version 4," on pages 151-157. Sometimes a router or the destination host has to inform the sender of the packet of a problem that occurred while processing that packet. In the TCP/IP protocol suite, this reporting is done by the Internet Control Message Protocol (ICMP). How are these messages generated by the ICMP?

• 5.2.3: IP version 6 (IPv6)

  • Université Catholique de Louvain: Olivier Bonaventure's "Computer Networking: Principles, Protocols, and Practice" URL

    Read section 5.2.3, "IP version 6," on pages 157-164. As the popularity of the Internet grew exponentially, it became necessary for an expanded addressing architecture, IP version 6 (IPv6). This section discusses how IPv6 has resolved a number of routing issues while becoming the new standard.

• 5.2.4: ICMP Version 6 (ICMPv6)

  • Université Catholique de Louvain: Olivier Bonaventure's "Computer Networking: Principles, Protocols, and Practice" URL

    Read section 5.2.4, "ICMP version 6," on pages 164-166. ICMPv6 is the companion protocol for IPv6, just as ICMPv4 is the companion protocol for IPv4. ICMPv6 is used by routers and hosts to report problems when processing IPv6 packets. In addition, ICMPv6 is used when auto-configuring addresses. This section discusses messaging for IPv6.

• 5.2.5: Middleboxes

  • Université Catholique de Louvain: Olivier Bonaventure's "Computer Networking: Principles, Protocols, and Practice" URL

    Read the introduction to section 5.2.5, "Middleboxes." Stop at "Firewalls," which you will read below. As you read, consider the following questions: What is a Middlebox? Why do we need them?

  • 5.2.5.1: Firewalls

    • Université Catholique de Louvain: Olivier Bonaventure's "Computer Networking: Principles, Protocols, and Practice" URL

      Read "Firewalls" on pages 166-168. Stop at "NAT," which you will read below. As you read, consider the following questions: When you first used your computer to access the Internet, what was the first security technique you heard about? How does a firewall protect your system from the "evil-doers" lurking on the Internet?

  • 5.2.5.2: Network Address Translation (NAT)

    • Université Catholique de Louvain: Olivier Bonaventure's "Computer Networking: Principles, Protocols, and Practice" URL

      Read "NAT" on pages 168-169. Stop at section 5.3 "Routing in IP networks."

      Large corporations and government agencies prefer their networks to be private (that is, not seen on the Internet). In this section, explore the concept of private networks to learn how their need to communicate with the outside world and with specific machines under certain conditions has resulted in NAT; the mechanism that allows private networks to communicate openly with the outside world. How does NAT work?