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IPv6 Internet Protocol, Version 6

IPv6 Internet Protocol, Version 6. Yen-Cheng Chen NCNU ycchen@ncnu.edu.tw. IP v6 - Version Number. IP v 1-3 defined and replaced IP v4 - current version IP v5 - streams protocol IP v6 - replacement for IP v4 During development it was called IPng Next Generation. IPv6 RFCs.

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IPv6 Internet Protocol, Version 6

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  1. IPv6Internet Protocol, Version 6 Yen-Cheng Chen NCNU ycchen@ncnu.edu.tw

  2. IP v6 - Version Number • IP v 1-3 defined and replaced • IP v4 - current version • IP v5 - streams protocol • IP v6 - replacement for IP v4 • During development it was called IPng • Next Generation

  3. IPv6 RFCs • 1752 - Recommendations for the IP Next Generation Protocol • 2460 – IPv6 specification • 2373 - addressing structure • others (find them) http://playground.sun.com/pub/ipng/html/specs/specifications.html

  4. Why Change IP? • Address space exhaustion • Two level addressing (network and host) wastes space • Network addresses used even if not connected to Internet • Growth of networks and the Internet • Extended use of TCP/IP • Single address per host • Requirements for new types of service

  5. Changes from IPv4 to IPv6 • Expanded Addressing Capabilities • Header Format Simplification • Improved Support for Options • Flow LabelingCapabilities • Authentication and Privacy Capabilities

  6. IPv6 Enhancements • Expanded address space • 128 bit • Improved option mechanism • Separate optional headers between IPv6 header and transport layer header • Most are not examined by intermediate routes • Improved speed and simplified router processing • Easier to extend options • Address autoconfiguration • Dynamic assignment of addresses

  7. IPv6 Enhancements (2) • Increased addressing flexibility • Anycast - delivered to one of a set of nodes • Improved scalability of multicast addresses • Support for resource allocation • Replaces type of service • Labeling of packets to particular traffic flow • Allows special handling • e.g. real time video

  8. IP v6 Header

  9. IP v6 Header Fields (1) • Version • 6 • Traffic Class • Classes or priorities of packet • Still under development • See RFC 2460 • Flow Label • Used by hosts requesting special handling • Payload length • Includes all extension headers plus user data

  10. IP v6 Header Fields (2) • Next Header • Identifies type of header • Extension or next layer up • Source Address • Destination address

  11. IPv6 Extension Headers • Hop-by-Hop options header • Require processing at each router • Routing header • Similar to IPv4 source routing • Fragment header • Destination options header • For destination node • Authentication header (RFC 2402) • Encrypted security payload (RFC 2406)

  12. IPv6 Extension Headers Without Extension Headers IPv6 Header Next Header= TCP Data TCP Header With Extension Headers Data IPv6 Header Next Header= Routing Routing Header Next Header= TCP TCP Header Data IPv6 Header Next Header= Routing Routing Header Next Header= Fragment Fragment Header Next Header= TCP TCP Header

  13. Options NH HEL Hop-by-Hop Options • Next header (8-bit) • Header extension length (8-bit) • Options • Jumbo payload (RFC 2675) • Over 216 = 65,535 octets • Router alert (RFC 2711) • Tells the router that the contents of this packet is of interest to the router • Provides support for RSVP

  14. Option Data Options • Type-Length-Value (TLV) • Option Type (8-bit) • Option Data Length (8-bit) • Option Data (variable) Option Type Option Data Length

  15. Type-Specific Data Next Header Hdr Ext Len Routing Type Segments Left Routing Header • List of one or more intermediate nodes to be visited • Next Header • Header extension length • Routing type • Segments left • i.e. number of nodes still to be visited

  16. Next Header Hdr Ext Len RT = 0 Segments Left Reserved Address[1] Address[2] . . . Address[n]

  17. Fragmentation Header • Fragmentation only allowed at source • No fragmentation at intermediate routers • Node must perform path discovery to find smallest MTU of intermediate networks • Source fragments to match MTU • Otherwise limit to 1280 octets

  18. Fragmentation Header Fields • Next Header • Reserved • Fragmentation offset • Reserved • More flag • Identification

  19. Options NH HEL Destination Options • Same format as Hop-by-Hop options header

  20. IPv6 Addresses • 128 bits long • Assigned to interface • Single interface may have multiple unicast addresses • Three types of address

  21. Types of address • Unicast • Single interface • Anycast • Set of interfaces (typically different nodes) • Delivered to any one interface • the “nearest” • Multicast • Set of interfaces • Delivered to all interfaces identified

  22. Text Representation of IPv6 Addresses • x:x:x:x:x:x:x:x • hexadecimal values of the eight 16-bit pieces of the address. • FEDC:BA98:7654:3210:FEDC:BA98:7654:3210 • 1080:0:0:0:8:800:200C:417A

  23. IPv6 Address Representation (2) • The use of "::" indicates multiple groups of 16-bits of zeros. • Unicast address • 1080:0:0:0:8:800:200C:417A • 1080::8:800:200C:417A • Multicast address • FF01:0:0:0:0:0:0:101  FF01::101 • Loopback address • 0:0:0:0:0:0:0:1  ::1 • unspecified addresses • 0:0:0:0:0:0:0:0  ::

  24. IPv6 Address Representation (3) • IPv4 and IPv6 mixed address • x:x:x:x:x:x:d.d.d.d • x: IPv6, d: IPv4 • Eg. • 0:0:0:0:0:FFFF:129.144.52.38 • ::13.1.68.3 • ::FFFF:129.144.52.38

  25. Allocation Prefix Fraction Reserved 0000 0000 1/256 Unassigned 0000 0001 1/256 Reserved for NSAP Allocation 0000 001 1/128 Reserved for IPX Allocation 0000 010 1/128 Unassigned 0000 011 1/128 Unassigned 0000 1 1/32 Unassigned 0001 1/16 Aggregatable Global Unicast Addresses 001 1/8 Unassigned 010 1/8 Unassigned 011 1/8 Unassigned 100 1/8 Unassigned 101 1/8 Unassigned 110 1/8 Unassigned 1110 1/16 Unassigned 1111 0 1/32 Unassigned 1111 10 1/64 Unassigned 1111 110 1/128 Unassigned 1111 1110 0 1/512 Link-Local Unicast Addresses 1111 1110 10 1/1024 Site-Local Unicast Addresses 1111 1110 11 1/1024 Multicast Addresses 1111 1111 1/256

  26. Unicast Addresses • global aggregatable global unicast address • NSAP address • IPX hierarchical address • site-local address • link-local address • IPv4-capable host address

  27. IPv6 Unicast Addresses 128 bits node address 128-n bits n bits subnet prefix interface ID

  28. IPv6 Addresses with Embedded IPv4 Addresses • IPv4-compatible IPv6 address • IPv4-mapped IPv6 address 80 bits 16 32 bits 0000……………………0000 0000 IPv4 Addresses 80 bits 16 32 bits 0000……………………0000 FFFF IPv4 Addresses

  29. Aggregatable Global Unicast Addresses FP Format Prefix (001) TLA ID Top-Level Aggregation Identifier RES Reserved for future use NLA ID Next-Level Aggregation Identifier SLA ID Site-Level Aggregation Identifier INTERFACE ID Interface Identifier

  30. Local-Use IPv6 Unicast Addresses • Link-Local Unicast Addresses • Site-Local Unicast Addresses FE80::x:x:x:x 64 bits 54 bits 10 bits 1111111010 0 Interface ID FEC0::s:x:x:x:x 64 bits 16 bits 38 bits 10 bits 1111111011 Subnet ID 0 Interface ID

  31. Multicast Addresses 8 bits 112 bits 4 bits 4 bits 11111111 Group ID Flags Scope 0000 : well known 0001 : transient

  32. Multicasting • Addresses that refer to group of hosts on one or more networks • Uses • Multimedia “broadcast” • Teleconferencing • Database • Distributed computing • Real time workgroups

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