1. CS 447 Networks and Data Communication Department of Computer Science Southern Illinois University Edwardsville Fall, 2015 Dr. Hiroshi Fujinoki E-mail: hfujino@siue.edu IP Address Format, Classes Sub-Networking and Class-less Inter Domain Routing

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

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

4. 10.0.0.0 - 10.255.255.255 172.16.0.0 - 172.31.255.255 192.168.0.0 - 192.168.255.255 Class-A Private IP Addresses: Class-B Private IP Addresses: Class-C Private IP Addresses: IP_Address/004 What is IP address? CS 447 Networks and Data Communication

5. IP Address Format (for IPv4) 1. General Expression IP Address = “xxx. xxx. xxx. xxx” Each “xxx” = “0” to “255” Example “146.163.146.170” 2. Internal Format “146.163.146.170” = 32 bits 1 23 IP_Address/008 CS 447 Networks and Data Communication

6. 32 bits 123 IP Address Format (for IPv4) Section 1: Class-ID Field (1 to 4 bits) 0: Class-A IP addresses 10: Class-B IP addresses 110: Class-C IP addresses 1110: Class-D IP addresses (Multicast Address) Section 2: Domain Address Field (7 to 21 bits) Section 3: Host Address Field (8 to 24 bits) IP_Address/009 CS 447 Networks and Data Communication

7. Internet Domain and host addresses IP_Address/010 Domain X Domain Y Gateway Router in Domain X Destination Host Routing using domain address Routing using host address Transmitting Host Gateway Router in Domain Y CS 447 Networks and Data Communication

8. 0 IP Address Format (for IPv4) Class-A Domain Address Host Address 7 bits 24 bits 01 7831 Bit #s: 1 0 Class-B Domain AddressHost Address 14 bits 16 bits 02 1516 31 Bit #s: 1 1 1 0 Class-C Domain AddressHost Address 21 bits 8 bits 02 2324 31 Bit #s: 13 IP_Address/011 CS 447 Networks and Data Communication

9. IP Address Format (for IPv4) Class-A Class-B Class-C IP_Address/012 Number of hosts in a domain Number of domains in the Internet = up to (2 24 - 1) hosts/domain = up to 2 7 domains One of the addresses in a domain must be “domain broadcast” address Number of hosts in a domain = up to (2 16 - 1) hosts/domain Number of domains in the Internet = up to 2 14 domains Number of domains in the Internet Number of hosts in a domain = up to (2 8 - 1) hosts/domain = up to 2 21 domains CS 447 Networks and Data Communication

10. Example of IP address construction “146.163.146.170” What are the bit patterns for “146”, “163” and “170”? MSBLSB 123 4 5678 128 - 18 1 16 - 2 1 1 00 000 146  18  12864321684 21 Weight “146” IP_Address/013 CS 447 Networks and Data Communication

11. MSBLSB 123 4 5678 12864321684 21 128 - 35 1 32 - 3 1 1 0 0 00 163  35  Weight “163” IP_Address/014 Example of IP address construction 2 - 1  3 1 CS 447 Networks and Data Communication

12. MSBLSB 123 4 5678 12864321684 21 170 128 - 42 1 32 - 10 42 1 1 00 0 0    Weight “170” IP_Address/015 Example of IP address construction 8 - 2 10 1 CS 447 Networks and Data Communication

13. Example of IP address construction “146.163.146.170” IP_Address/016 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 146170 SIUE’s IP Class = Class-B Internet domain SIUE’s domain address = “146.163” Class-ID Domain Address Host Address It is customary to include the class-ID as a part of the domain address My server’s host address = “146.170” CS 447 Networks and Data Communication

14. IP_Address/017 Two extensions in IP address formats 1. Subnet and Subnet Masks 2. CIDR (Class-less Inter Domain Routing) A mechanism to make managing IP addresses easier Partitioning a network domain within a domain A mechanism to increase the number of network domains Partitioning a network domain into more than one network domain Purpose Method CS 447 Networks and Data Communication

15. IP_Address/018 Subnet and Subnet Masks The problemManaging IP addresses in a large domain is not an easy job SIUE Domain (146.163.X.X) 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 host Assigned IP address CS 447 Networks and Data Communication

16. IP_Address/019 Subnet and Subnet Masks The problemManaging IP addresses in a large domain is not an easy job SIUE Domain (146.163.X.X) Your job is to assign, maintain and manage all available IP addresses in SIUE domain. Assigned IP address You can not assign an IP address to more than one host (or NIC) CS 447 Networks and Data Communication

17. SIUE Domain (146.163.X.X) IP_Address/020 Subnet and Subnet Masks Two solutions  Dynamic address assignment (DHCP)  Subnet working DHCP Server DHCP Query DHCP Reply 1ABF Problem in DHCP Every time you starts your PC, your IP address may be different MAC Address IP Address IPMAC 146.163.0.1 146.163.0.4 146.163.0.3 146.163.0.2 1ABF NULL CS 447 Networks and Data Communication

18. SIUE Domain (146.163.X.X) IP_Address/021 Subnet and Subnet Masks Partition the entire domain Assign a group of IP addresses to each partition Each partition is called “subnet” Address range: 146.163.0.1-146.163.3.255 Address range: 146.163.4.1-146.163.7.255 Address range: 146.163.8.1-146.163.12.255 CS 447 Networks and Data Communication

19. IP_Address/022 CIDR (Class-less Inter-Domain Routing) The “3-class” design in the existing IP (IPv4) is not very efficient Lack of flexibility in domain size Example Suppose that your organization has 5,000 host computers. - Which IP class you need? - What is the address space utilization? Class-B is required Class-C is up to 2 8 = 256 hosts Class-B is up to 2 16 = 6,5536 hosts Address space utilization = (what you have) (what you can have) = 5,000/6,5536 = 7.6% If this is usually the case, the IPv4’s address space is never big enough CS 447 Networks and Data Communication

20. IP_Address/023 Only three different address classes What is the cause of the problem? How can/should we increase “address classes”?  Restructure the IP address format IP address format needs to be re-defined How long will it take? How much will it cost?  Apply some extension to the exiting IP (IPv4) (IPv6 uses this approach) CIDR (Class-less Inter-Domain Routing) CS 447 Networks and Data Communication

21. IP_Address/024 CIDR (Class-less Inter-Domain Routing) How does CIDR work? 0 Class-A Domain Address Host Address 7 bits 24 bits 01 7831 Bit #s: 1 0 Class-B Domain AddressHost Address 14 bits 16 bits 02 1516 31 Bit #s: 1 1 1 0 Class-C Domain AddressHost Address 21 bits 8 bits 02 2324 31 Bit #s: 13 This is the mistake in IPv4!! CS 447 Networks and Data Communication

22. IP_Address/025 CIDR (Class-less Inter-Domain Routing)  Eliminate “class IDs” This is how it is called “class-less”. 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 CS 447 Networks and Data Communication

23. IP_Address/026 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 146170 Network Address Bits Example If we need only up to 4,000 hosts? Since 2 12 = 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 146170 Network Address Bits We can come up with (2 4 -1) more domains of the same size! CS 447 Networks and Data Communication

24. IP_Address/028 CIDR (Class-less Inter-Domain Routing) CIDR Block PreFix # Equivalent Class-C # of Host Addresses /272 (32-27) 1/8 of a Class-C 2 5 /2 8 = 1/2 3 /26 /25 /24 /14 /15 /16 /17 256 Class-C (Class-B) 1/4 of a Class-C 1/2 of a Class-C 1 Class-C 128 Class-C 512 Class-C 1024 Class-C 2 (32-26) 2 (32-25) 2828 2 16 2 (32-17) 2 17 2 18 = 32 = 64 = 128 = 256 = 32,768 = 65,536 = 131,072 = 262,144 CS 447 Networks and Data Communication

25. Internet IP_Address/003 241.12.57.88 Exception #1 Private IP addresses 172.16.0.1 172.16.0.2 172.16.0.9 172.16.0.100 NAT IP Masquerade CS 447 Networks and Data Communication

26. Internet Exception #2 Multicast IP addresses (Class-D IP addresses) A transmitting host transmits once Multiple hosts receives at once Transmitting Host Multiple Receiving Hosts IP_Address/005 CS 447 Networks and Data Communication

27. Internet Exception #2 Multicast IP addresses (Class-D IP addresses) Transmitting Host All the receivers should receive messages A sender should transmit only once All the receivers should have the same multicast IP addresses IP_Address/006 CS 447 Networks and Data Communication

28. SIUE Domain Internet IP_Address/007 Transmitting Host Local-Domain Multicast Global-Internet Multicast FirstLast Categories 224.0.0.0224.0.0.255 224.0.1.0238.255.255.255 239.0.0.0 239.255.255.255 Local-Domain Multicast Global-Internet Multicast Global-Internet Reserved We developed a UDP IP-multicast audio-streaming application applications in CS490 (Fall 2005) (as SIUE’s local-domain multicast). CS 447 Networks and Data Communication

29. Domain Address Host Address ? bits

30. 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 146170