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Introducing IPv6 and Defining IPv6 Addressing

Introducing IPv6 and Defining IPv6 Addressing. BSCI Module 8 Lessons 1 and 2. Objectives. Explain the need for IPv6 address space. Explain how IPv6 deals with the limitations of IPv4. Describe the features of IPv6 addressing.

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Introducing IPv6 and Defining IPv6 Addressing

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  1. Introducing IPv6 and Defining IPv6 Addressing BSCI Module 8 Lessons 1 and 2

  2. Objectives • Explain the need for IPv6 address space. • Explain how IPv6 deals with the limitations of IPv4. • Describe the features of IPv6 addressing. • Describe the structure of IPv6 headers in terms of format and extension headers. • Show how an IPv6 address is represented. • Describe the three address types used in IPv6.

  3. Introducing IPv6

  4. Why Do We Need a Larger Address Space? • Internet population • Approximately 973 million users in November 2005 • Emerging population and geopolitical and address space • Mobile users • PDA, pen-tablet, notepad, and so on • Approximately 20 million in 2004 • Mobile phones • Already 1 billion mobile phones delivered by the industry • Transportation • 1 billion automobiles forecast for 2008 • Internet access in planes – Example: Lufthansa • Consumer devices • Sony mandated that all its products be IPv6-enabled by 2005 • Billions of home and industrial appliances

  5. IP Address Allocation History In 1981, IPv4 Protocol was published. In 1985, about 1/16 of the total IPv4 address space was in use. By mid-2001, about 2/3 of the total IPv4 address space was in use.

  6. Larger address space Global reachability and flexibility Aggregation Multihoming Autoconfiguration Plug-and-play End to end without NAT  Renumbering Simpler header Routing efficiency Performance and forwarding rate scalability No broadcasts No checksums Extension headers Flow labels IPv6 Advanced Features

  7. Mobility and security Mobile IP RFC-compliant IPSec mandatory(or native) for IPv6 Transition richness Dual stack 6to4 tunnels Translation IPv6 Advanced Features (Cont.)

  8. Larger Address Space IPv4 • 32 bits or 4 bytes long • 4,200,000,000 possible addressable nodes IPv6 • 128 bits or 16 bytes: four times the bits of IPv4 • 3.4 * 1038 possible addressable nodes • 340,282,366,920,938,463,374,607,432,768,211,456 • 5 * 1028 addresses per person ~= ~= ~= ~=

  9. Larger Address Space Enables Address Aggregation • Aggregation of prefixes announced in the global routing table • Efficient and scalable routing • Improved bandwidth and functionality for user traffic

  10. Self Check • How much of the address space was in use by mid-2001? • How many bits are included in an IPv6 address? • How will IPv6 enable smaller routing tables in Internet routers? • Why is NAT not a requirement for IPv6?

  11. Defining IPv6 Addressing

  12. Simple and Efficient Header A simpler and more efficient header means: • 64-bit aligned fields and fewer fields • Hardware-based, efficient processing • Improved routing efficiency and performance • Faster forwarding rate with better scalability

  13. MTU Issues • Minimum link MTU for IPv6 is 1280 octets(vs. 68 octets for IPv4). • On links with MTU < 1280, link-specific fragmentation and reassembly must be used • Implementations are expected to perform path MTU discovery to send packets bigger than 1280. • Minimal implementation can omit PMTU discovery as long as all packets kept ≤ 1280 octets. • A hop-by-hop option supports transmission of “jumbograms” with up to 232 octets of payload.

  14. Version IHL Type of Service Total Length Version Traffic Class Flow Label Identification Flags Fragment Offset Payload Length Next Header Hop Limit Time to Live Protocol Header Checksum Source Address Source Address Destination Address Options Padding Destination Address IPv4 and IPv6 Header Comparison IPv4 Header IPv6 Header Field’s Name Kept from IPv4 to IPv6 Fields Not Kept in IPv6 Name and Position Changed in IPv6 New Field in IPv6 Legend

  15. IPv6 Extension Headers Simpler and more efficient header means: • IPv6 has extension headers. • IPv6 handles the options more efficiently. • IPv6 enables faster forwarding rate and end nodes processing.

  16. IPv6 Address Representation • x:x:x:x:x:x:x:x,where xis a 16-bit hexadecimal field • Leading zeros in a field are optional: • 2031:0:130F:0:0:9C0:876A:130B • Successive fields of 0 can be represented as ::, but only once per address. • Examples: • 2031:0000:130F:0000:0000:09C0:876A:130B • 2031:0:130f::9c0:876a:130b • FF01:0:0:0:0:0:0:1 >>> FF01::1 • 0:0:0:0:0:0:0:1 >>> ::1 • 0:0:0:0:0:0:0:0 >>> ::

  17. IPv6—Addressing Model • Addresses are assigned to interfaces • Change from IPv4 mode: • Interface “expected” to have multiple addresses • Addresses have scope • Link Local • Unique Local • Global • Addresses have lifetime • Valid and preferred lifetime Link Local Global Unique Local

  18. IPv6 Address Types • Unicast • Address is for a single interface. • IPv6 has several types (for example, global and IPv4 mapped). • Multicast • One-to-many • Enables more efficient use of the network • Uses a larger address range • Anycast • One-to-nearest (allocated from unicast address space). • Multiple devices share the same address. • All anycast nodes should provide uniform service. • Source devices send packets to anycast address. • Routers decide on closest device to reach that destination. • Suitable for load balancing and content delivery services.

  19. IPv6 Global Unicast (and Anycast)Addresses The global unicast and the anycast share the same address format. • Uses a global routing prefix—a structure that enables aggregation upward, eventually to the ISP. • A single interface may be assigned multiple addresses of any type (unicast, anycast, multicast). • Every IPv6-enabled interface must contain at least one loopback (::1/128) and one link-local address. • Optionally, every interface can have multiple unique local and global addresses. • Anycast address is a global unicast address assigned to a set of interfaces (typically on different nodes). • IPv6 anycast is used for a network multihomed to several ISPs that have multiple connections to each other.

  20. IPv6 Global Unicast Addresses (Cont.) • Global unicast and anycast addresses are defined by a global routing prefix, a subnet ID, and an interface ID.

  21. IPv6 Unicast Addressing • IPv6 addressing rules are covered by multiple RFCs. • Architecture defined by RFC 4291. • Unicast: One to one • Global • Link local (FE80::/10) • A single interface may be assigned multiple IPv6 addresses of any type: unicast, anycast, or multicast.

  22. Self Check • Describe the MTU discovery process used by IPv6 devices. • Why is the IP checksum header not used in IPv6 implementations? • How are successive zeros represented in an IPv6 address? • What are 3 types of IPv6 addresses? • Which address type from IPv4 was eliminated in IPv6?

  23. Summary • IPv6 is a powerful enhancement to IPv4. Features that offer functional improvement include a larger address space, simplified header, and mobility and security. • IPv6 increases the number of address bits by a factor of four, from 32 to 128. • The IPv6 header has 40 octets and is simpler and more efficient than the IPv4 header. • IPv6 addresses use 16-bit hexadecimal number fields separated by colons (:) to represent the 128-bit addressing format. • The three types of IPv6 addresses are unicast, multicast, and anycast.

  24. Q and A

  25. Resources • IPv6 Addressing At-A-Glance • http://cisco.com/application/pdf/en/us/guest/tech/tk872/c1550/cdccont_0900aecd8026003d.pdf • IPv6 Extension Headers Review and Considerations • http://cisco.com/en/US/partner/tech/tk872/technologies_white_paper0900aecd8054d37d.shtml • IPv6 Headers At-A-Glance • http://cisco.com/application/pdf/en/us/guest/tech/tk872/c1482/cdccont_0900aecd80260042.pdf

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