CS 447 Networks and Data Communication IP Address Format, Classes Sub-Networking and Class-less Inter Domain Routing Department of Computer Science Southern Illinois University Edwardsville Fall, 2017 Dr. Hiroshi Fujinoki E-mail: hfujino@siue.edu

CS 447 Networks and Data Communication What is IP address? IP address is the ID for each NIC at a host computer Internet Backbone Carrier (long distance carrier) ISPs NIC NIC Internet Host Y Host X SIUE Domain Internet core routers IP_Address/001

CS 447 Networks and Data Communication What is IP address? Every IP address must be unique Advantage in using IP addresses You can use the same format of IP address no matter where your destination is. Host Q 241.12.57.88 146.163.146.170 202.1.0.5 32.123.72.55 Internet Host Y Host X SIUE Domain Host S IP_Address/002 Host Z

CS 447 Networks and Data Communication What is IP address? 10.0.0.0 - 10.255.255.255 172.16.0.0 - 172.31.255.255 192.168.0.0 - 192.168.255.255 IP Addresses = the unique identifiers for each host computer (NIC) in the Internet (or intranets) IP_Address/003

CS 447 Networks and Data Communication CIDR (Class-less Inter-Domain Routing)  Each IP address = a combination of “domain address” and “host address” Domain Address Host Address ? bits 32-bit IPv4 address  Only the source and destination network domains perform CIDR This is how it is called “inter-domain routing”. The gateway routers in your transmitting host and the destination host perform CIDR IP_Address/004

CS 447 Networks and Data Communication CIDR (Class-less Inter-Domain Routing) 146.163.146.170/16 “CIDR Prefix” = How many bits (from the top) are “network address” 1 0 0 1 0 0 1 0 . 1 0 1 0 0 0 1 1. 1 0 0 1 0 0 1 0.1 0 1 0 1 0 1 0 146 163 170 Network Address Bits Example If we need only up to 4,000 hosts? We can come up with (24-1) more domains of the same size! Since 212 = 4,096, we need only 12 bits for host address filed. 146.163.146.170/20 1 0 0 1 0 0 1 0 . 1 0 1 0 0 0 1 1. 1 0 0 1 0 0 1 0.1 0 1 0 1 0 1 0 146 163 170 Network Address Bits IP_Address/005

CS 447 Networks and Data Communication Domain and host addresses Destination Host Domain X Transmitting Host Domain Y Routing using host address Routing using domain address Gateway Router in Domain Y Gateway Router in Domain X Internet IP_Address/006

CS 447 Networks and Data Communication Example of IP address construction “146.163.146.170” What are the bit patterns for “146”, “163” and “170”? “146” MSB LSB 1 2 3 4 5 6 7 8 128 64 32 16 8 4 2 1 Weight 1 1 1 146  18  - 128 - 16 18 2 IP_Address/007

CS 447 Networks and Data Communication Example of IP address construction “163” MSB 1 2 3 4 5 6 7 8 LSB Weight 128 64 32 16 8 4 2 1 1 1 1 1 163  35   3 - 128 - 32 - 1 2 35 3 IP_Address/008

CS 447 Networks and Data Communication Example of IP address construction “170” MSB 1 2 3 4 5 6 7 8 LSB Weight 128 64 32 16 8 4 2 1 1 1 1 1    170 42 10 - 128 - 32 - 8 42 10 2 IP_Address/009

CS 447 Networks and Data Communication Two extensions in IP address formats 1. Subnet and Subnet Masks 2. CIDR (Class-less Inter Domain Routing) Purpose A mechanism to make managing IP addresses easier Partitioning a network domain within a domain Method Purpose A mechanism to increase the number of network domains Partitioning a network domain into more than one network domain Method IP_Address/010

CS 447 Networks and Data Communication Subnet and Subnet Masks The problem Managing IP addresses in a large domain is not an easy job SIUE domain has more than 1,000 host computers IP address must be unique You can’t assign an IP address to more than one NIC SIUE Domain (146.163.X.X) Assigned IP address IP_Address/011

CS 447 Networks and Data Communication Subnet and Subnet Masks The problem Managing IP addresses in a large domain is not an easy job Your job is to assign, maintain and manage all available IP addresses in SIUE domain. You can not assign an IP address to more than one host (or NIC) SIUE Domain (146.163.X.X) Assigned IP address IP_Address/012

CS 447 Networks and Data Communication Subnet and Subnet Masks Two solutions  Dynamic address assignment (DHCP)  Subnet working IP MAC 146.163.0.1 146.163.0.4 146.163.0.3 146.163.0.2 1ABF NULL SIUE Domain (146.163.X.X) MAC Address DHCP Query DHCP Server DHCP Reply 1ABF MAC Address IP Address Problem in DHCP Every time you starts your PC, your IP address may be different IP_Address/013

CS 447 Networks and Data Communication Subnet and Subnet Masks Partition the entire domain Assign a group of IP addresses to each partition Address range: 146.163.4.1-146.163.7.255 SIUE Domain (146.163.X.X) Address range: 146.163.8.1-146.163.12.255 Address range: 146.163.0.1-146.163.3.255 Each partition is called “subnet” IP_Address/014

CS 447 Networks and Data Communication Exception in IP addresses (#1) 172.16.0.1 172.16.0.2 172.16.0.9 172.16.0.100 • • • Private IP addresses 241.12.57.88 NAT Internet IP Masquerade IP_Address/015

CS 447 Networks and Data Communication Exception in IP addresses (#2) Multicast IP addresses (Class-D IP addresses) A transmitting host transmits once Multiple hosts receives at once Multiple Receiving Hosts Transmitting Host Internet IP_Address/016

CS 447 Networks and Data Communication Exception in IP addresses (#2) Multicast IP addresses (Class-D IP addresses) All the receivers should receive messages All the receivers should have the same multicast IP addresses A sender should transmit only once Transmitting Host Internet IP_Address/017

CS 447 Networks and Data Communication Global-Internet Multicast Transmitting Host Internet Local-Domain Multicast SIUE Domain First Last Categories 224.0.0.0 224.0.0.255 Global-Internet Reserved 224.0.1.0 238.255.255.255 Global-Internet Multicast 239.0.0.0 239.255.255.255 Local-Domain Multicast We developed a UDP IP-multicast audio-streaming application applications in CS490 (Fall 2005) (as SIUE’s local-domain multicast). IP_Address/018

CS 447 Networks and Data Communication CIDR (Class-less Inter-Domain Routing) CIDR Block PreFix # Equivalent Class-C # of Host Addresses 25/28 = 1/23 /27 1/8 of a Class-C 2(32-27) = 32 /26 /25 /24 /14 /15 /16 /17 1/4 of a Class-C 2(32-26) 2(32-25) 28 216 2(32-17) 217 218 = 64 = 128 = 256 = 32,768 = 65,536 = 131,072 = 262,144 1/2 of a Class-C 1 Class-C 128 Class-C 256 Class-C (Class-B) 512 Class-C 1024 Class-C IP_Address/000