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IPv6

IPv6. Internet Protocol Version 6. Internet Protocol Version 6 (IPv6). IPv6 solutions to IPv4 disadvantages IPv6 addressing IPv6 header DNS support for IPv6 Core protocols of IPv6 IPv6 Neighbor Discovery Differences between IPv4 and IPv6. Disadvantages of IPv4. Limited address space

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IPv6

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  1. IPv6 Internet Protocol Version 6

  2. Internet Protocol Version 6 (IPv6) • IPv6 solutions to IPv4 disadvantages • IPv6 addressing • IPv6 header • DNS support for IPv6 • Core protocols of IPv6 • IPv6 Neighbor Discovery • Differences between IPv4 and IPv6

  3. Disadvantages of IPv4 • Limited address space • Flat routing infrastructure • Configuration • Security • Quality of service (QoS) • Mobility

  4. IPv6 Solutions to IPv4 Disadvantages • Huge address space • Hierarchical routing infrastructure • Automatic configuration • Built-in security • Better support for QoS • Built-in mobility

  5. 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 ~= ~= ~= ~=

  6. IPv6 Adressing IPv6 addresses per person 6.5 Billion people on earth IPv6 addresses for every human brain cell on the planet Typical braincell has ~100 Billion cells (your count may vary)

  7. 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

  8. The IPv6 Address Space • 128-bit address space • 128 bits were chosen to allow multiple levels of hierarchy and flexibility in designing hierarchical addressing and routing • Global unicast and anycast addresses are defined by a global routing prefix, a subnet ID, and an interface ID

  9. 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 >>> ::

  10. Compressing Zeros • Some IPv6 addresses contain long sequences of zeros • A single contiguous sequence of 16-bit blocks set to 0 can be compressed to “::” (double-colon) • Examples: • FE80:0:0:0:2AA:FF:FE5F:47D1 becomes FE80::2AA:FF:FE5F:47D1 • FEC0:0:0:41CD:2AA:FF:FE5F:47D1 becomes FEC0::41CD:2AA:FF:FE5F:47D1 • FF02:0:0:0:0:0:0:1 (a multicast address) becomes FF02::1

  11. IPv6 Prefixes • Prefix is the part of the address where the bits have fixed values or are the bits of a route or subnet identifier • IPv6 subnets or routes always uses address/prefix-length notation • CIDR notation • Examples: • 3FFE:FFFF:2A:41CD::/64 is a subnet identifier • 3FFE:FFFF:2A::/48 is a route • FF::/8 is an address range

  12. Types of IPv6 Addresses • Unicast • Address of a single interface • One-to-one delivery to single interface • Multicast • Address of a set of interfaces • One-to-many delivery to all interfaces in the set • Anycast • Address of a set of interfaces • One-to-one-of-many delivery to a single interface in the set that is closest • No more broadcast addresses

  13. Unicast IPv6 Addresses • Global addresses • Used on IPv6 Internet • Equivalent to IPv4 public addresses • Local-Use Addresses • Site-local addresses • Equivalent to IPv4 private addresses • Always begin with FEC0 • Link-local addresses • Equivalent to APIPA addresses • Always begin with FE80 Link Local Global Site Local

  14. IPv6 Interface Identifiers • Based on: • Derived from the MAC address of the network adapter to which the address is assigned • Randomly generated to provide IPv4-equivalent anonymity • Assigned during a Point-to-Point Protocol (PPP) connection • Assigned during DHCP configuration

  15. 00 90 27 17 17 17 FC FC FC 0F 0F 0F FF FF FF FE FE FE 00 02 90 90 27 27 000000U0 IPv6 Interface identifier EUI-64 • Cisco uses the extended universal identifier (EUI)-64 format to do stateless autoconfiguration. • This format expands the 48-bit MAC address to 64 bits by inserting “FFFE” into the middle 16 bits. • To make sure that the chosen address is from a unique Ethernet MAC address, the universal/local (U/L bit) is set to 1 for global scope (0 for local scope). Mac address 48 bit 00 90 27 17 FC 0F 64 bit 1 = Unique 0 = Not Unique U =

  16. 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 IPv6 Header 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

  17. Ethernet header IPv6 header Routing header Frag header Auth header ESP header TCP header Application data IPv6 Extension Header types • Routing Header • Fragmentation Header • Hop-by-Hop Options Header • Destinations Options Header • Authentication Header • Encrypted Security Payload Header

  18. DNS Support for IPv6 • AAAA resource records for name-to-address resolutions • PRT resource records in the IP6.ARPA reverse domain for address-to-name resolutions

  19. Core Protocols of IPv6 • IPv6 • Replacement for IPv4 • ICMPv6 • Replacement for ICMP for IPv4 • Neighbor Discovery • Replacement for ARP, Redirect, and Router Discovery for IPv4 • Multicast Listener Discovery • Replacement for IGMPv2 for IPv4

  20. IPv6 Neighbor Discovery • Messages • Neighbor Solicitation • Neighbor Advertisement • Router Solicitation • Router Advertisement • Redirect • Processes • Address resolution • Duplicate address detection • Router discovery • Redirect • Neighbor unreachability detection

  21. Stateless Autoconfiguration • A router sends network information to all the nodes on the local link. • A host can autoconfigure itself by appending its IPv6 interface identifier (64-bit format) to the local link prefix (64 bits). • The result is a full 128-bit address that is usable and guaranteed to be globally unique.

  22. A Standard Stateless Autoconfiguration • Stage 1: The PC sends a router solicitation to request a prefix for stateless autoconfiguration.

  23. A Standard Stateless Autoconfiguration (Cont.) • Stage 2: The router replies with a router advertisement.

  24. Differences Between IPv4 and IPv6 Feature IPv4 IPv6 Address length 32 bits 128 bits Header size 20-60 bytes 40 bytes IPSec support Optional Required QoS support Some Better Fragmentation Hosts and routers Hosts only Checksum in header Yes No Options in header Yes No Link-layer address resolution ARP (broadcast) Multicast Neighbor Discovery Messages Multicast membership IGMP Multicast Listener Discovery (MLD) Router Discovery Optional Required Uses broadcasts? Yes No Configuration Manual, DHCP Automatic, DHCP DNS name queries Uses A records Uses AAAA records DNS reverse queries Uses IN-ADDR.ARPA Uses IP6.ARPA

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