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IPv6 簡介

0 1 2 3 4 5 6. IPv6 簡介. National Dong Hwa University Director of Computer Center Han-Chieh Chao 趙涵捷 中華民國九十年三月三十日. Overview. Limitations of current Internet Protocol (IP) How many address do we need? IPv6 addressing IPv6 header format IPv6 features Mobile IPv6 IPv6 v.s. IPv4 Summary.

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IPv6 簡介

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  1. 0 1 2 3 4 5 6 IPv6簡介 National Dong Hwa University Director of Computer Center Han-Chieh Chao 趙涵捷 中華民國九十年三月三十日

  2. Overview • Limitations of current Internet Protocol (IP) • How many address do we need? • IPv6 addressing • IPv6 header format • IPv6 features • Mobile IPv6 • IPv6 v.s. IPv4 • Summary

  3. IPv4 Addresses • Example: 203.64.105.100 =1100 1011:0100 0000:0110 1001:0110 0100 = CB:40:69:64 (32 bits) • Maximum = 232 = 4 Billion • Class A Network: 15 Million nodes • Class B Network: 64,000 nodes or less • Class C Network: 250 nodes or less

  4. IPv4 Address 0 Network Local • Class A • Class B • Class C • Class D 1 17 24 bits 10 Network Local 2 14 16 bits 110 Network Local 3 21 8 bits 1110 Host Group (Multicast) bits 4 28

  5. IPv4 Address • Local = Subnet + Host (Variable length) Router Router Subnet

  6. IPv4 Address Format • Three all-zero network numbers are reserved • 127 Class A + 16,381 Class B + 2,097,151 Class C Network = 2,113,659 networks total • Class B is most popular • 20% of Class B were assigned by 7/90 and doubling every 14 months => Will exhaust by 3/94 • Question: Estimate how big will you become? Answer: more than 256! Class C is too small. Class B is just right.

  7. IPv6 Main Features/Functionality • Expanded Address Space • Header Format Simplification • Auto-configuration • Multi-Homing • Class of Service/Multimedia support • Authentication and Privacy Capabilities • No more broadcast Multicast • IPv4 IPv6 Transition Strategy

  8. How many address? • 10 Billion people by 2020 • Each person will be served by more than one computer • Assuming 100 computers per person => 1012 computers • More addresses maybe required since • Multiple interfaces per node • Multiple addresses per interfaces

  9. How many address? • Some believe 26 to 28 address per host • Safety margin => 1015 addresses • IPng Requirements => 1012 end systems and 109 networks. Desirable 1012 to 1015 networks

  10. Colon-Hex Notation • Dot-Decimal: 203.64.105.100 • Colon-Hex: FEDC:0000:0000:0000:3243:0000:0000:ABCD • Can skip leading zeros of each word • Can skip one sequence of zero words, e.g., FEDC::3243:0000:0000:ABCD • Can leave the last 32 bits in dot-decimal, e.g., ::203.64.105.100 • Can specify a prefix by /length, e.g., 2345:BA23:7::/40

  11. IPv6 Addressing Examples • Global unicast address(es) is : • 2001:304:101:1::E0:F726:4E58, • subnet is 2001:304:101:1::0/64 • link-local address is FE80::E0:F726:4E58 • Unspecified Address is 0:0:0:0:0:0:0:0 or :: • Loopback Address is 0:0:0:0:0:0:0:1 or ::1 • Group Addresses (Multicast), ie: FF02::9 for RIPv6 • Joined group address(es): • FF02:0:0:0:0:1:FF:xxxx (solicited Node Multicast) • Unicast : 4037::01:800:200E:8C6C is FF02::1:FF0E:8C6C

  12. IPv6 Address • 128-bit long. Fixed size • 2128 = 3.4×1038 addresses => 665×1021 addresses per m2 of earth surface • If assigned at the rate of 106/s, it would take 20 years • Expected to support 8×1017 to 2×1033 addresses 8×1017 => 1,564 address per m2 • Allows multiple interfaces per host • Allows multiple addresses per interface

  13. IPv6 Address • Allows unicast, multicast, anycast • Allows provider based, site-local, link-local • 85% of the space is unassigned

  14. IPv6 Addressing • IPv6 Addressing rules are covered by multiples RFC’s • Architecture defined by RFC 2373 • Address Types are : • Unicast : One to One (Global, Link local, Site local, Compatible) • Anycast : One to Nearest (Allocated from Unicast) • Multicast : One to Many • Reserved • A single interface may be assigned multiple IPv6 addresses of any type (unicast, anycast, multicast) • No Broadcast Address -> Use Multicast

  15. Unicast Anycast Multicast

  16. IPv6 Addressing • Prefix Format (PF) Allocation • PF = 0000 0000 : Reserved • PF = 0000 001 : Reserved for OSI NSAP Allocation (see RFC 1888), so far only way to embedded E.164 addresses (VoIP) • PF = 0000 010 : Reserved for IPX Allocation (under Study) • PF = 001 : Aggregatable Global Unicast Address • PF = 1111 1110 10 : Link Local Use Addresses • PF = 1111 1110 11 : Site Local Use Addresses • PF = 1111 1111 : Multicast Addresses • Other values are currently Unassigned (approx. 7/8th of total) • All Prefix Formats have to have EUI-64 bits Interface ID • But Multicast

  17. FP TLA ID Reserved NLA ID SLA ID Interface ID 3 bits 13 bits 8 bits 24 bits 16 bits 64 bits Global Unicast Addresses (RFC 2374) • Aggregatable Global Unicast Format - RFC2374 • Address hierarchy matches Internet Service Provider hierarchy • Terminology: • FP - Format Prefix: Unicast (001), Multicast, Anycast • TLA - Top Level Aggregator  Global ISP • NLA - Next Level Aggregator  ISP • SLA - Site Level Aggregator  “Customer” • Interface ID - Host

  18. IPv6 Prefix Allocation

  19. IPv6 Addressing Model • Addresses are assigned to interfaces • No change from IPv4 Model • Interface can have multiple addresses • Addresses have scope • Link Local • Site Local • Global • Addresses have lifetime • Valid and Preferred lifetime Site-Local Link-Local Global

  20. Local-Use Address • Link Local: Not forwarded outside the link, FE80::xxx • Site Local: Not forwarded outside the site, FEC0::xxx 10 n 118-n bits 1111 1110 10 0 Interface ID 10 n m 118-n-m bits 1111 1110 11 0 Subnet ID Interface ID

  21. Multicast Address 8bits 4bits 4bits 112bits • T=0 => Permanent (well-known) multicast address, T=1 => Transient • Scope: 1 Node-local, 2 Link-local, 5 Site-local, 8 Organization-local, E Global • Predefined: 1=>All nodes, 2=>Routers, 1:0=>DHCP Servers 1111 1111 Flags Scope Group ID 0 0 0 T

  22. Multicast Address • Example: 43 => Network Time Protocol Servers • FF01::43 => All NTP servers on this node • FF02::43 => All NTP servers on this link • FF05::43 => All NTP servers in this site • FF08::43 => All NTP servers in this organization • FF0F::43 => All NTP servers in the Internet

  23. FP NLA ID SLA ID Interface ID TLA ID subTLA ID 3 bits 19 bits 16 bits 64 bits 13 bits 13 bits IPv6 AddressesBootstrap phase • Bootstrap process - RFC2450 • Definitions: • TLA - special TLA 0x0001 • subTLA - Top Level Aggregator  Transit ISP • NLA - Next Level Aggregator  ISP • SLA - Site Level Aggregator  “Customer” • Interface ID - Host

  24. IPv6 AddressesBootstrap phase • Minimum assignment to ISP is a /35 • ISP creates own NLA boundary - or - • ISP assigns /48 SLAs to each customer • 16 bits for subnetworks • 65536 subnetworks per site • 64 bits for hosts • 18446744073710 million hosts per subnetwork!!

  25. site addresses ISP addresses NLA ID SLA ID Interface ID ISP allocated subTLA 13 bits 35 bits 16 bits 64 bits site addresses ISP addr ISP2 addr SLA ID Interface ID ISP allocated subTLA NLA2 NLA1 35 bits 16 bits 64 bits 6 bits 7 bits IPv6 AddressesBootstrap phase • subTLA holder ISP allocates SLAs to end-customers • subTLA holder ISP creates its own NLA boundary for customer ISPs

  26. IPv6 AddressesBootstrap phase • Where to get address space? • Real IPv6 address space now allocated by APNIC, ARIN and RIPE NCC • APNIC 2001:0200::/23 • ARIN 2001:0400::/23 • RIPE NCC 2001:0600::/23 • Go to your existing IPv4 address registry...

  27. APNIC (whois.apnic.net) WIDE-JP-19990813 2001:200::/35 NUS-SG-19990827 2001:208::/35 CONNECT-AU-19990916 2001:210::/35 NTT-JP-19990922 2001:218::/35 KIX-KR-19991006 2001:220::/35 JENS-JP-19991027 2001:228::/35 ETRI-KRNIC-KR-19991124 2001:230::/35 HINET-TW-20000208 2001:238::/35 IIJ-JPNIC-JP-20000308 2001:240::/35 IMNET-JPNIC-JP-20000314 2001:248::/35 CERNET-CN-20000426 2001:250::/35 INFOWEB-JPNIC-JP-2000502 2001:258::/35 BIGLOBE-JPNIC-JP-20000719 2001:260::/35 6DION-JPNIC-JP-20000829 2001:268::/35 DACOM-BORANET-20000908 2001:270::/35 ODN-JPNIC-JP-20000915 2001:278::/35 KOLNET-KRNIC-KR-20000927 2001:280::/35 TANET-IPV6-TW 2001:288::/35 ARIN (whois.arin.net) ESNET-V6 2001:400::/35 ARIN-001 2001:400::/23 VBNS-IPV6 2001:408::/35 CANET3-IPV6 2001:410::/35 VRIO-IPV6-0 2001:418::/35 CISCO-IPV6-0 2001:420::/35 QWEST-IPV6-0 2001:428::/35 DEFENSENET 2001:430::/35 ABOVENET-IPV6 2001:438::/35 SPRINT-V6 2001:440::/35 IPv6 Address SpaceCurrent Allocations This output current as of 16-Oct-2000

  28. RIPE (whois.ripe.net) EU-UUNET-19990810 2001:600::/35 DE-SPACE-19990812 2001:608::/35 NL-SURFNET-19990819 2001:610::/35 UK-BT-19990903 2001:618::/35 CH-SWITCH-19990903 2001:620::/35 AT-ACONET-19990920 2001:628::/35 UK-JANET-19991019 2001:630::/35 DE-DFN-19991102 2001:638::/35 RU-FREENET-19991115 2001:640::/35 GR-GRNET-19991208 2001:648::/35 DE-ECRC-19991223 2001:650::/35 DE-TRMD-20000317 2001:0658::/35 FR-RENATER-20000321 2001:0660::/35 DE-NACAMAR-20000403 2001:0668::/35 EU-EUNET-20000403 2001:0670::/35 DE-IPF-20000426 2001:0678::/35 DE-XLINK-20000510 2001:0680::/35 FR-TELECOM-20000623 2001:0688::/35 PT-RCCN-20000623 2001:0690::/35 SE-SWIPNET-20000828 2001:0698::/35 PL-ICM-20000905 2001:06A0::/35 IPv6 Address SpaceCurrent Allocations This output current as of 16-Oct-2000

  29. Changed Removed IPv4 Header20 Octets+Options : 13 fields, include 3 flag bits 0 bits 4 8 16 24 31 Ver IHL Service Type Total Length Identifier Flags Fragment Offset Time to Live Protocol Header Checksum 32 bit Source Address 32 bit Destination Address Options and Padding

  30. IPv4 Header Type of Service Total Length IHL Version Flags Fragment Offset Identification Protocol Header Checksum Time to Live Source Address Destination Address Options Padding IPv6 Header Traffic Class Flow Label Version Payload Length Next Header Hop Limit Source Address Destination Address IPv6 - So what’s really changed ?! • Defined by RFC 2460 • Address space quadrupled to 16 bytes • Fixed length • (Optional headers daisy-chained) • No checksumming • (Done by Link Layer) • No hop-by-hop segmentation • (Path MTU discovery) • Flow label/Class (Integrated QoS support) • Concatenated Extension Headers

  31. IPv6 Header40 Octets, 8 fields 0 4 12 16 24 31 Version Class Flow Label Payload Length Next Header Hop Limit 128 bit Source Address 128 bit Destination Address

  32. Protocol and Header Types

  33. IPv6 Extension Headers • IP options have been moved to a set of optional Extension Headers • Extension Headers are chained together IPv6 Header TCP Header Application Data Next = TCP IPv6 Header Routing Hdr TCP Header Application Data Next = Routing Next = TCP IPv6 Header Security Hdr Fragment Hdr TCP Header Data Frag Next = Security Next = Frag Next = TCP

  34. Routing Header Next Header Routing Type Num. Address Next Address Reserved Strict/Loose bit mask Address 1 Address 2 ….. Address n

  35. Next header and extension headers

  36. Routing Header • Strict => Discard if Address[Next-Address]  neighbor • Type = 0 => Current source routing • Type > 0 => Policy based routing (later) • New Functionality: Provider selection, Host mobility, Auto-readdressing (route to new address)

  37. IPv6 Features • Larger Addresses • Flexible header format • Improved options • Support for resource allocation • Provision for protocol extension • Built-in Security: Both authentication and confidentiality

  38. Address Autoconfiguration • Allow plug and play • BOOTP and DHCP are used in IPv4 • DHCPng will be used with IPv6 • Two Methods: Stateless and Stateful • Stateless: • A system uses link-local address as source and multicasts to "All routers on this link" • Router replies and provides all the needed prefix info • All prefixes have a associated lifetime • System can use link-local address permanently if no router

  39. Messages communication of the Stateless Autoconfiguration.

  40. Flow Chart of the Stateless Autoconfiguration.

  41. Address Autoconfiguration • Stateful: • Problem w stateless: Anyone can connect • Routers ask the new system to go DHCP server (by setting managed configuration bit) • System multicasts to "All DHCP servers" • DHCP server assigns an address

  42. Automatic Renumbering • Renumbering IPv6 Hosts is easy • Add a new Prefix to the Router • Reduce the Lifetime of the old prefix • As nodes depreciate the old prefix the new Prefix will start to be used for new connections • Renumbering in IPv6 is designed to happen! • An end of ISP “lock in”! • Improved competition

  43. Putting the IT Director back in control • IPv6 Address Scope • Some addresses are GLOBAL • Others are Link or Site LOCAL • Addressing Plan also controls network access • Configuration Policy Control • Stateless • Stateful (DHCPv6) • Routers Dictate the Configuration Policy • Router Managers are “in control” of the network • Routers also dictate MTU size for the Link

  44. Mobile IPv6 • IPv6 Mobility is based on core features of IPv6 • The base IPv6 was designed to support Mobility • Mobility is not an “Add-on” features • All IPv6 Networks are IPv6-Mobile Ready • All IPv6 nodes are IPv6-Mobile Ready • All IPv6 LANs / Subnets are IPv6 Mobile Ready • IPv6 Neighbor Discovery and Address Autoconfiguration allow hosts to operate in any location without any special support

  45. Mobile IPv6 • No single point of failure (Home Agent) • More Scalable : Better Performance • Less traffic through Home Link • Less redirection / re-routing (Traffic Optimisation)

  46. Mobile IPv6 Status • Interactions with IPsec fully worked out • Mobile IPv6 testing event • Bull, Ericsson, NEC, INRIA • Internet Draft is ready for Last Call

  47. IPv6 - Mandates Security • Security features are standardized and mandated • All implementations must offer them • No Change to applications • Authentication (Packet signing) • Encryption (Data Confidentiality) • End-to-End security Model • Protects DHCP • Protects DNS • Protects IPv6 Mobility • Protects End-to-End traffic over IPv4 networks

  48. IPv6 v.s. IPv4 • 1995 v.s. 1975 • IPv6 only twice the size of IPv4 header • Only version number has the same position and meaning as in IPv4 • Removed: header length, type of service, identification, flags, fragment offset, header checksum • Datagram length replaced by payload length • Protocol type replaced by next header

  49. IPv6 v.s. IPv4 • Time to live replaced by hop limit • Added: Priority and flow label • All fixed size fields • No optional fields. Replaced by extension headers • 8-bit hop limit = 255 hops max (Limits looping) • Next Header = 6 (TCP), 17 (UDP)

  50. IPv6 Features and Advantages • Larger Address Space • Efficient and Extensible IP datagram • Efficient Route Computation and Aggregation • Improved Host and Router Discovery • Mandated New Stateless and Stateful Address Autoconfiguration • Mandated Security for IP datagrams • Easy renumbering

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