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IP Addressing – Part 1. MIS 4700 – Advanced Networking Dr. Garrett. IP Addressing Basics. Computers deal with network addresses in the form of bit patterns IP uses a three-part addressing scheme Symbolic: Example “support.dell.com” Logical numeric: Example 172.16.1.10
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IP Addressing – Part 1 MIS 4700 – Advanced Networking Dr. Garrett
IP Addressing Basics • Computers deal with network addresses in the form of bit patterns • IP uses a three-part addressing scheme • Symbolic: Example “support.dell.com” • Logical numeric: Example 172.16.1.10 • Physical numeric: Consists of a 6-byte numeric address, burned into firmware (on a chip) by network interface manufacturers
IP Addressing Basics (cont.) • Data Link Sublayers Layers • Media Access Control (MAC) • Logical Link Control (LLC) sublayer • At the Data Link layer, a network interface transfers frames, using MAC addresses, to another network interface only on the same physical or local network • At the Network layer, the sender’s address and the ultimate recipient’s address is in the IP packet header
Anatomy Of An IP Address • IP addresses use dotted decimal notation • IP Addresses take the form n.n.n.n, where n is guaranteed to be between 0 and 255 • Each number is an 8-bit number that is called an octet
IP Address Classes • IP addresses are further subdivided into five classes, from Class A to Class E • First three classes of addresses (A thru C), divide the octets as follows • Class A n. h.h.h • Class B n.n. h.h • Class C n.n.n. h • n = Network, h = Hosts
IP Address Classes (cont.) • Address Classes D and E are for special uses • Class D addresses are used for multicast communications • Class E addresses are reserved entirely for experimental use
More About Class A Addresses • Expressed in binary form, Class A addresses always take the following binary form: • 0bbbbbbb.bbbbbbbb.bbbbbbbb.bbbbbbbb • b = 1 or 0 • 00000000 thru 01111111 for first octet • Addresses consisting of all 0s and all 1s, for the variable “b”, are reserved for special uses • Network ID and Broadcast Address • Address 127.n.n.n is reserved for loopback testing
More About Class B Addresses • Class B addresses always take the following binary form: • 10bbbbbb.bbbbbbbb.bbbbbbbb.bbbbbbbb • b = 1 or 0 • 10000000 thru 10111111 for first octet • Addresses consisting of all 0s and all 1s, for the variable “b”, are reserved for special uses • Network ID and Broadcast Address
More About Class C Addresses • Class C addresses always take the following binary form • 110bbbbb.bbbbbbbb.bbbbbbbb.bbbbbbbb • b = 1 or 0 • 11000000 thru 11011111 for first octet • Addresses consisting of all 0s and all 1s, for the variable “b”, are reserved for special uses • Network ID and Broadcast Address
More About Address Classes D And E • Class D addresses always take the following binary form: • 1110bbbb.bbbbbbbb.bbbbbbbb.bbbbbbbb • b = 1 or 0 • 11100000 thru 11101111 for first octet • Class E addresses always take the following binary form: • 11110bbb.bbbbbbbb.bbbbbbbb.bbbbbbbb • b = 1 or 0 • 11110000 thru 11110111 for first octet
Network, Broadcast, Multicast, And Other Special IP Addresses • Network addresses cannot identify a particular host on a network • Network addresses have all 0s in the host bit positions • Broadcast Address is the address that all hosts on a network must read • Broadcast addresses have all 1s in the host bit positions • Broadcast Frame and Packet Structures • Network Packet Broadcast 255.255.255.255 • Data Link Frame Broadcast 0xFF-FF-FF-FF-FF-FF • Multicast packet and address structures
Multicast And Other Special IP Addresses (cont.) • Host uses a service that employs a multicast address • Host registers itself to “listen” on that address • Data Link layer destination address is based on the Network layer multicast address
Vanishing IP Address Space • Mid-1990s experts began to predict that the Internet would “run out” of available IP addresses • Address space saving techniques • Classless Inter-Domain Routing (CIDR) • Trade in existing IP network addresses ($) • RFC 1918 private IP addresses range • Network Address Translation (NAT) lets networks use private IP addresses internally and maps them to public IP address externally