Agenda Understanding need for IPv6 History of IPv4 Internet Modern Internet Needs of Modern Internet Understanding IPv6 Direct/Indirect Communication IPv6 Communication in LAN IPv6 Communication over WAN IPv6 Migration Strategies Understanding Impact on Hardware and Software Techniques of Partial and Full Migration IPv6 Applications and Services Enabling IPv6 in LAN Enabling IPv6 in WAN Using Applications and Services via IPv6
History of IPv4 Internet
History of Internet Advanced Research Projects Agency of the Department of Defense (ARPA) Implemented the ARPAnet, the grandparent of today’s Internet Packet switching Digital data is sent in small packages called packets Packets Contain data, address information, error-control information and sequencing information Transmission Control Protocol (TCP) ensures that messages are properly sent from sender to receiver and that those messages arrive intact
Internetworking Protocol (IP) –De-facto Standard –Enabled the intercommunication of inter-organization and intra-organization packet based networks. The Internet was initially limited to universities and research institutions History of Internet … contd.
History of Internet - Addresses Addresses provide information on how to locate something, e.g., what route to take from here to there. Internet addresses combine –a routing portion, known as the network part –a name portion known as the host part How to split an Internet address into the network part and the host part has changed over time… How to get there from here!!!
Back when the TCP/IP protocols were first being designed, there was a big argument between fixed length and variable length addresses –Fixed length will always be limited But if you make it big enough, no one will be interested –Variable length will always take more cycles to process But there are tricks you can play to minimize the difference The decision was made for fixed, 32 bit addresses –Rumor has it, by a flip of a coin... History of Internet – Addresses … contd.
History of Internet – Internet Address Structure 32 bit unsigned integers –possible values 0 - 4,294,967,295 Typically written as a “dotted quad of octets” –four 8 bit values with a range of separated by “.” –For example, can be written as below
History of Internet … Internet Address Structure E E Originally, the architects of the Internet thought 256 networks would be more than enough –Assumed a few very large (16,777,216 hosts) networks Addresses were partitioned as below –8 bit network part, 24 bit host part
Original addressing plan too limiting –More than 256 networks with many fewer hosts than 2 24 Solution was to create address classes History of Internet – Classfull Addressing