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Next Generation IP National Dong Hwa University Director of Computer Center Han-Chieh Chao 中華民國八十九年十月十九日 TANET2000 TWNIC IPv6 研討會.

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Presentation on theme: "Next Generation IP National Dong Hwa University Director of Computer Center Han-Chieh Chao 中華民國八十九年十月十九日 TANET2000 TWNIC IPv6 研討會."— Presentation transcript:

1 Next Generation IP National Dong Hwa University Director of Computer Center Han-Chieh Chao 中華民國八十九年十月十九日 TANET2000 TWNIC IPv6 研討會

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: = : : : = CB:40:69:64 (32 bits) Maximum = 2 32 = 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 Class A Class B Class C Class D 0 Network Local 10 Network Local 110 Network Local 1110 Host Group (Multicast) bits

5 IPv4 Address Local = Subnet + Host (Variable length) 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 How many address? 10 Billion people by 2020 Each person will be served by more than one computer Assuming 100 computers per person => computers More addresses maybe required since –Multiple interfaces per node –Multiple addresses per interfaces

8 How many address? Some believe 2 6 to 2 8 address per host Safety margin => addresses IPng Requirements => end systems and 10 9 networks. Desirable to networks

9 Address Size H Ratio = log 10 (number of objects)/available bits 2 n objects with n bits: H Ratio = log 10 2 = French telephone moved from 8 to 9 digits at 10 7 households => H = 0.26 (assuming 3.3 bits/digit) US telephone expanded area codes with 10 8 subscribers => H = 0.24 SITA expanded 7-character address at 64k nodes => H = 0.14 (assuming 5 bits/char)

10 Address Size Physics/space science net stopped at nodes using 16-bit addresses => H = Million Internet hosts currently using 32-bit addresses => H = 0.20 => A few more years to go

11 IPv6 Address 128-bit long. Fixed size = 3.4×10 38 addresses => 665×10 21 addresses per m 2 of earth surface If assigned at the rate of 106/  s, it would take 20 years Expected to support 8×10 17 to 2×10 33 addresses 8×10 17 => 1,564 address per m 2 Allows multiple interfaces per host Allows multiple addresses per interface

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

13 Colon-Hex Notation Dot-Decimal: 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., :: –Can specify a prefix by /length, e.g., 2345:BA23:7::/40

14 IPv6 Prefix Allocation

15 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 Link-LocalSite-Local Global

16 Local-Use Address Link Local: Not forwarded outside the link, FE80::xxx Site Local: Not forwarded outside the site, FEC0::xxx Interface ID 10n118-nbits Subnet ID Interface ID bitsn10m118-n-m

17 Multicast Address 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 Flags Scope Group ID T 4bits8bits112bits4bits

18 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

19 IPv4 Header 20 Octets+Options : 13 fields, include 3 flag bits 0 bits31 VerIHLTotal Length IdentifierFlagsFragment Offset 32 bit Source Address 32 bit Destination Address Service Type Options and Padding Time to LiveHeader ChecksumProtocol RemovedChanged

20 IPv6 Header 40 Octets, 8 fields 031 VersionClassFlow Label Payload LengthNext HeaderHop Limit 128 bit Source Address 128 bit Destination Address

21 Protocol and Header Types

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

23 Routing Header Next HeaderRouting TypeNum. Address ReservedStrict/Loose bit mask Address 1 Address 2 Next Address Address n …..

24 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)

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

26 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

27 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

28 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

29 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

30 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

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

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

33 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

34 IPv6 v.s. IPv v.s 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

35 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)

36 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

37 Transition Mechanisms Dual-IP Hosts, Routers, Name servers Tunneling IPv6 over IPv4 Hosts and Routers can be gradually upgraded to IPv6 It is better (though not required) to upgrade routers before upgrading hosts HITACHI Toolnet6

38 Interoperability 6over4 –Isolated v6 to isolated v6 node –IPv4 used as link layer 6to4 –v6 domain to v6 domain –IPv4 used as transport tunnel NAT-PT –v6 only to v4 only SIIT, AIIH, DTI, BIS, …

39 Application Issues Most application protocols will have to be upgraded: FTP, SMTP, Telnet, Rlogin 27 of 51 Full Internet standards, 6 of 20 draft standards, 25 of 130 proposed standards will be revised for IPv6 No checksum => checksum at upper layer is mandatory, even in UDP non-IETF standards: X-Open, Kerberos,... will be updated Should be able to request and receive new DNS records

40 Implementation 4.4-lite BSD by US Naval Research Laboratory UNIX, OpenVMS by DEC DOS/WINDOWS by FTP Software HP-UX SICS (Swedish Institute of Comp. Science) Linux NetBSD by INRIA Rocquencourt Solaris 2 by Sun Streams by Mentat

41 Summary IPv6 uses 128-bit addresses Allows provider-based, site-local, link-local, multicast, anycast addresses Fixed header size. Extension headers instead of options. Extension headers for provider selection, security Allows autoconfiguration Dual IP router and host implementations for transition


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