《IPv6技术培训》_2 - 从政策看IPv6

TSB A Policy look at IPv6 Richard hill april 2003 Telecommunication standardization bureau International telecommunication union Based on a paper by John Klensin, available at http:/web/itudoc/itu-t/com2/infodocs/015.html

1 TSB A Policy Look at IPv6 Richard Hill April, 2003 Telecommunication Standardization Bureau International Telecommunication Union Based on a paper by John Klensin, available at: http://web/itudoc/itu-t/com2/infodocs/015.html

TSB O utline What is IPv6 Address space exhaustion Relationship to topology Alternatives to ipv6 · Network problems Space allocation policy Deployment difficulties Roadblocks and solutions · ITU and ipy6 · about the itu

2 TSB Outline • What is IPv6 • Address space exhaustion • Relationship to topology • Alternatives to IPv6 • Network problems • Space allocation policy • Deployment difficulties • Roadblocks and solutions • ITU and IPv6 • About the ITU

TSB What is IPv6 IPv6 (Internet Protocol, version 6)was developed by the Internet Engineering Task Force (ete), starting in 1993, in response to a series of perceived problems, primarily with exhaustion of the current ip version 4 IPv4), address space

3 TSB What is IPv6 • IPv6 (Internet Protocol, version 6) was developed by the Internet Engineering Task Force (IETF), starting in 1993, in response to a series of perceived problems, primarily with exhaustion of the current, IP version 4 (IPv4), address space

TSB Address space exhaustion(1/3) Rate and scale of Internet growth was underestimated In 1970s, 32-bit address space was thought to be adequate for long term Class system(A, B, C) Internet routing is closely tied to the separation of routing within a network and routing between networks

4 TSB Address space exhaustion (1/3) • Rate and scale of Internet growth was underestimated • In 1970’s, 32-bit address space was thought to be adequate for long term • Class system (A, B, C) • Internet routing is closely tied to the separation of routing within a network and routing between networks

TSB Address space exhaustion(2/3) Routing within large networks became complex Sub-netting introduced advent of pcs meant that each host could no longer have a unique fixed ip address dynamic address assignment(but reachability?) private address spaces(but leakage if connected to public network)

5 TSB Address space exhaustion (2/3) • Routing within large networks became complex • Sub-netting introduced • Advent of PCs meant that each host could no longer have a unique fixed IP address – dynamic address assignment (but reachability?) – private address spaces (but leakage if connected to public network)

TSB Address space exhaustion(3/3) In 1995, classless system was introduced RiRs became more conservative with respect to address allocation Some believe ipya addresses will be exhausted in 2-3 years, others in 10 years others sooner others much later Rate of exhaustion influenced b technology(e.g NATing) and rir policies as well as growth Under-use of certain class a.b allocations

6 TSB Address space exhaustion (3/3) • In 1995, classless system was introduced • RIRs became more conservative with respect to address allocation • Some believe IPv4 addresses will be exhausted in 2-3 years, others in 10 years, others sooner, others much later. • Rate of exhaustion influenced by technology (e.g. NATing) and RIR policies as well as growth • Under-use of certain class A, B allocations

TSB Relationship to topology (1/3) An ip address is not similar to a telephone number An ip address is a routing address ° In telephony terms a telephone number is more like a domain name an ip address is more like a sanc

7 TSB Relationship to topology (1/3) • An IP address is not similar to a telephone number • An IP address is a routing address • In telephony terms: – a telephone number is more like a domain name – an IP address is more like a SANC

TSB Relationship to topology(2/3) But analogies are imperfect Telephone numbers identify a circuit, a wire going somewhere, but are now portable IP addresses identify a terminal device, a computer. but can be dynamically assigned translated (NATing)

8 TSB Relationship to topology (2/3) • But analogies are imperfect – Telephone numbers identify a circuit, a wire going somewhere, but are now portable – IP addresses identify a terminal device, a computer, but can be: • dynamically assigned • translated (NATing)

TSB Relationship to topology (3/3) Back to the basics of internet Any host can access any other host through uniform protocols and addresses · Network is dumb Intelligence at the edges applications independent of network Network does not change content These differences are more important than the packet vs. switched models

9 TSB Relationship to topology (3/3) • Any host can access any other host through uniform protocols and addresses • Network is dumb • Intelligence at the edges • Applications independent of network • Network does not change content Back to the basics of Internet: These differences are more important than the packet vs. switched models

TSB Alternatives to Ipv6 Application servers at boundary of public network, translate to private network but these gateways can limit functionality NATing, VPNS, private spaces, but may force re-numbering NATing limits peer-to-peer applications IPsec requires end-to-end

10 TSB Alternatives to IPv6 • Application servers at boundary of public network, translate to private network, but these gateways can limit functionality • NATing, VPNs, private spaces, but may force re-numbering – NATing limits peer-to-peer applications – IPsec requires end-to-end