1. Microcomputer Networking II St. Cloud State University MCS 426, Fall 1999 Instructor: Adomas Svirskas TCP/IP addressing Addressing basics Address classes Address administration

2. Microcomputer Networking II St. Cloud State University MCS 426, Fall 1999 Instructor: Adomas Svirskas IP addressing Each network interface in TCP/IP network is assigned a unique 32-bit internet address that is used in all communications with that host - IP address IP Address encodes both host and network numbers Host and address numbers depend on address class

3. Microcomputer Networking II St. Cloud State University MCS 426, Fall 1999 Instructor: Adomas Svirskas Figure from book Computer Networks 3rd ed., by A.S. Tanenbaum IP addressing Class A - up to 126 networks with 16777214 hosts each Class B - up to 16,382 networks with 65534 hosts each Class C - up to 2097152 networks with 254 hosts each

4. Microcomputer Networking II St. Cloud State University MCS 426, Fall 1999 Instructor: Adomas Svirskas Figure from book Computer Networks 3rd ed., by A.S. Tanenbaum IP addressing External representation - dotted decimal notation: 199.17.25.8 - each of the four bytes is written in decimal Subnets Subnet mask splits address into network and host numbers

5. Microcomputer Networking II St. Cloud State University MCS 426, Fall 1999 Instructor: Adomas Svirskas IP addressing An address which has all bits of the hostid equal to 0 is used to refer to the network An address which has all bits of the hostid equal to 1 is broadcast address - directed broadcast If address contains all 32 1s, it is used for limited broadcast All-zero address means “this host” All-zero network id means “this network”

6. Microcomputer Networking II St. Cloud State University MCS 426, Fall 1999 Instructor: Adomas Svirskas Figure from book Computer Networks 3rd ed., by A.S. Tanenbaum Special IP Addresses

7. Microcomputer Networking II St. Cloud State University MCS 426, Fall 1999 Instructor: Adomas Svirskas Weaknesses of IP addressing If a host computer moves from one network to another, its IP address must be changed Inflexible address space Delivery of packets to host with multiple interfaces depends on address used

8. Microcomputer Networking II St. Cloud State University MCS 426, Fall 1999 Instructor: Adomas Svirskas Internet Address Administration Internet addresses are managed centrally: –Internet Assigned Numbers Authority http://www.iana.org –Regional authorities: APNIC (Asia-Pacific Network Information Center) http://www.apnic.net ARIN (American Registry for Internet Numbers ) http://www.arin.net RIPE NCC (Reseau IP Europeens) http://www.ripe.net Internal IP address space: –192.168.0.0

9. Microcomputer Networking II St. Cloud State University MCS 426, Fall 1999 Instructor: Adomas Svirskas Figure from book Computer Networks and Internets., by D. Comer IP addressing example

10. Microcomputer Networking II St. Cloud State University MCS 426, Fall 1999 Instructor: Adomas Svirskas Figure from book Computer Networks and Internets., by D. Comer Routing example

11. Microcomputer Networking II St. Cloud State University MCS 426, Fall 1999 Instructor: Adomas Svirskas Network Byte Order Standard representation of data, independent of hardware platform TCP/IP protocols define network standard byte order Each router or host converts binary items to/from local representation from/to network standard byte order format Integers are sent most significant byte first (Big Endian style)