Brett NeelyIP Next Generation课件.ppt

What to do? The Internet address space as specified by IPv4 is currently filling up quickly. Options: Limit the total size of the Internet Disrupt the network by changing the technology Birth of IPv6 IETF started working on the problem of limited address space in late 1990 By February 1992, four separate proposals for an update to IPv4 were being worked on IETF formed IPng area in late 1993 An IPng working group BOF was held at July, 1994 Toronto IETF meeting The selected proposal for IPv6 is known as SIPP (Simple Internet Protocol Plus) SIPP originally had 64 bit IP addresses, which was later expanded to 128 bits Why IPv6? Running out of address space - expand size of Internet addresses Router tables grow at a rate 1.5 times the growth of computer memory technology - change routing methods to keep router tables manageable. IPv6 allows the creation of network hierarchies which will improve routing. Quality of Service: IPv6 has “quality of service” options. Certain Internet traffic flows can be “labeled” for special handling - useful for realtime audio and video. (example: RealAudio) Realtime transmissions need consistent throughput to provide regular service. How IPv6? A simple, flexible transition from IPv4 - Internet hosts can upgrade to IPv6 one at a time and not goof up the network. It would be impossible to get everyone to switch at the same time. It is possible that IPv4 and IPv6 will coexist on the Internet for several years Hosts keep existing IP addresses when they switch from IPv4 to IPv6 Most parts of the existing Internet will not have to be renumbered - Routers may be renumbered IPv6 Security The current Internet has many security problems, lacks security technology beneath the application layer IPv6 includes extensions which support authentication, integrity, and confidentiality (Friday’s lecture) These extensions appear as additional headers inside the IP packet Su