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Lecture TCP-IP protocol suite (3/e): Chapter 8 - Behrouz Forouzan

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Chapter 8 - Internet protocol. Upon completion you will be able to: Understand the format and fields of a datagram, understand the need for fragmentation and the fields involved, understand the options available in an IP datagram, be able to perform a checksum calculation, understand the components and interactions of an IP package. | Chapter 8 Upon completion you will be able to: Internet Protocol Understand the format and fields of a datagram Understand the need for fragmentation and the fields involved Understand the options available in an IP datagram Be able to perform a checksum calculation Understand the components and interactions of an IP package Objectives TCP/IP Protocol Suite Figure 8.1 Position of IP in TCP/IP protocol suite TCP/IP Protocol Suite 8.1 DATAGRAM A packet in the IP layer is called a datagram, a variable-length packet consisting of two parts: header and data. The header is 20 to 60 bytes in length and contains information essential to routing and delivery. TCP/IP Protocol Suite Figure 8.2 IP datagram TCP/IP Protocol Suite Figure 8.3 Service type or differentiated services TCP/IP Protocol Suite The precedence subfield was designed, but never used in version 4. Note: TCP/IP Protocol Suite Table 8.1 Types of service TCP/IP Protocol Suite Table 8.2 Default types of | Chapter 8 Upon completion you will be able to: Internet Protocol Understand the format and fields of a datagram Understand the need for fragmentation and the fields involved Understand the options available in an IP datagram Be able to perform a checksum calculation Understand the components and interactions of an IP package Objectives TCP/IP Protocol Suite Figure 8.1 Position of IP in TCP/IP protocol suite TCP/IP Protocol Suite 8.1 DATAGRAM A packet in the IP layer is called a datagram, a variable-length packet consisting of two parts: header and data. The header is 20 to 60 bytes in length and contains information essential to routing and delivery. TCP/IP Protocol Suite Figure 8.2 IP datagram TCP/IP Protocol Suite Figure 8.3 Service type or differentiated services TCP/IP Protocol Suite The precedence subfield was designed, but never used in version 4. Note: TCP/IP Protocol Suite Table 8.1 Types of service TCP/IP Protocol Suite Table 8.2 Default types of service TCP/IP Protocol Suite Table 8.3 Values for codepoints TCP/IP Protocol Suite The total length field defines the total length of the datagram including the header. Note: TCP/IP Protocol Suite Figure 8.4 Encapsulation of a small datagram in an Ethernet frame TCP/IP Protocol Suite Figure 8.5 Multiplexing TCP/IP Protocol Suite Table 8.4 Protocols TCP/IP Protocol Suite An IP packet has arrived with the first 8 bits as shown: Example 1 01000010 The receiver discards the packet. Why? Solution There is an error in this packet. The 4 left-most bits (0100) show the version, which is correct. The next 4 bits (0010) show the header length; which means (2 × 4 = 8), which is wrong. The minimum number of bytes in the header must be 20. The packet has been corrupted in transmission. TCP/IP Protocol Suite In an IP packet, the value of HLEN is 1000 in binary. How many bytes of options are being carried by this packet? Example 2 Solution The HLEN value is 8, which .