tailieunhanh - Lecture Routing Protocols and Concepts - Chapter 6: VLSM and CIDR

Chapter 6 introduce VLSM and CIDR. This chapter compare and contrast classful and classless IP addressing, review VLSM and explain the benefits of classless IP addressing, describe the role of the Classless Inter-Domain Routing (CIDR) standard in making efficient use of scarce IPv4 addresses. | VLSM and CIDR Routing Protocols and Concepts – Chapter 6 Objectives Compare and contrast classful and classless IP addressing. Review VLSM and explain the benefits of classless IP addressing. Describe the role of the Classless Inter-Domain Routing (CIDR) standard in making efficient use of scarce IPv4 addresses. Introduction Prior to 1981, IP addresses used only the first 8 bits to specify the network portion of the address In 1981, RFC 791 modified the IPv4 32-bit address to allow for three different classes IP address space was depleting rapidly The Internet Engineering Task Force (IETF) introduced Classless Inter-Domain Routing (CIDR) CIDR uses Variable Length Subnet Masking (VLSM) to help conserve address space VLSM is simply subnetting a subnet Classful and Classless IP Addressing Classful IP addressing As of January 2007, there are over 433 million hosts on internet Initiatives to conserve IPv4 address space include: VLSM & CIDR notation (1993, RFC 1519) Network Address . | VLSM and CIDR Routing Protocols and Concepts – Chapter 6 Objectives Compare and contrast classful and classless IP addressing. Review VLSM and explain the benefits of classless IP addressing. Describe the role of the Classless Inter-Domain Routing (CIDR) standard in making efficient use of scarce IPv4 addresses. Introduction Prior to 1981, IP addresses used only the first 8 bits to specify the network portion of the address In 1981, RFC 791 modified the IPv4 32-bit address to allow for three different classes IP address space was depleting rapidly The Internet Engineering Task Force (IETF) introduced Classless Inter-Domain Routing (CIDR) CIDR uses Variable Length Subnet Masking (VLSM) to help conserve address space VLSM is simply subnetting a subnet Classful and Classless IP Addressing Classful IP addressing As of January 2007, there are over 433 million hosts on internet Initiatives to conserve IPv4 address space include: VLSM & CIDR notation (1993, RFC 1519) Network Address Translation (1994, RFC 1631) Private Addressing (1996, RFC 1918) Classful and Classless IP Addressing The High Order Bits These are the leftmost bits in a 32 bit address Classful and Classless IP Addressing Classes of IP addresses are identified by the decimal number of the 1st octet Class A address begin with a 0 bit Range of class A addresses = to Class B address begin with a 1 bit and a 0 bit Range of class B addresses = to Class C addresses begin with two 1 bits & a 0 bit Range of class C addresses = to Classful and Classless IP Addressing The IPv4 Classful Addressing Structure (RFC 790) An IP address has 2 parts: The network portion Found on the left side of an IP address The host portion Found on the right side of an IP address Classful and Classless IP Addressing Classful and Classless IP Addressing Purpose of a subnet mask It is used to determine the network portion of an IP address Classful and Classless IP .