1. Introduction to Internet Protocol Version 6 Joseph Davies Technical writer Windows Networking and Device Technologies Microsoft Corporation

2. 2 Agenda Introduction to Internet Protocol Version 6 (IPv6) IPv6 addressing IPv6 header Internet Control Message Protocol for IPv6 (ICMPv6) and Multicast Listener Discovery (MLD) Neighbor Discovery Address autoconfiguration

3. 3 Introduction Problems with IPv4 IPv6 features IPv6 packets over local area network (LAN) media IPv6 implementations from Microsoft

4. 4 Problems with IPv4 Public address space becoming exhausted Large routing tables for Internet backbone routers Configuration could be simpler IP-layer security is not required Need better support for prioritized delivery

5. 5 IPv6 features New header format Large address space Efficient and hierarchical addressing and routing infrastructure Stateless and stateful address configuration

6. 6 IPv6 features (2) Built-in security Better support for prioritized delivery New protocol for neighboring node interaction Extensibility

7. 7 TCP/IP protocol architecture with IPv6 IPv6 TCP FTP UDP MLD TelnetHTTPRIPngDNSSNMP Internet Layer Transport Layer Application Layer Network Interface Layer Application Layer Presentation Layer Session Layer Transport Layer Network Layer Data Link Layer Physical Layer OSI Model Layers TCP/IP Protocol Architecture Layers TCP/IP Protocol Suite EthernetIEEE 802.11Frame RelayATM ND ICMPv6

8. 8 An IPv6 packet Payload IPv6 Header IPv6 Packet Network Interface Header Network Interface Trailer Network Interface Layer Frame

9. 9 IPv6 packets over LAN media Ethernet II encapsulation Uses EtherType value of 0x86DD IEEE 802.x encapsulation Uses Sub-Network Access Protocol (SNAP) header and EtherType value of 0x86DD

10. 10 IPv6 implementations from Microsoft Microsoft® Windows Server® 2003 family Microsoft Windows® XP Service Pack 1 (SP1) and Windows XP Service Pack 2 (SP2) Windows CE.NET version 4.1 and later versions Windows Vista™ (now in beta testing) and Windows Server "Longhorn" (now in beta testing) Installed and enabled by default

11. 11 IPv6 addressing The IPv6 address space IPv6 address syntax IPv6 address prefixes Unicast IPv6 addresses Multicast IPv6 addresses IPv6 interface identifiers DNS support

12. 12 The IPv6 address space 128-bit address space 2 128 possible addresses 340,282,366,920,938,463,463,374,607,431,768,211, 456 addresses (3.4 x 10 38 ) 6.6 x 10 23 addresses for every square meter of the Earth’s surface 128 bits were chosen to allow for flexibility in creating multilevel, hierarchical, routing infrastructure

13. 13 IPv6 address syntax IPv6 address in binary form 0010000000000001000011011011100000000000000000000010111100111011 0000001010101010000000001111111111111110001010001001110001011010

14. 14 IPv6 address syntax (2) IPv6 address in binary form 0010000000000001000011011011100000000000000000000010111100111011 0000001010101010000000001111111111111110001010001001110001011010 Divided along 16-bit boundaries 0010000000000001 0000110110111000 0000000000000000 0010111100111011 0000001010101010 0000000011111111 1111111000101000 1001110001011010

15. 15 IPv6 address syntax (3) IPv6 address in binary form 0010000000000001000011011011100000000000000000000010111100111011 0000001010101010000000001111111111111110001010001001110001011010 Divided along 16-bit boundaries 0010000000000001 0000110110111000 0000000000000000 0010111100111011 0000001010101010 0000000011111111 1111111000101000 1001110001011010 Each 16-bit block is converted to hexadecimal and delimited by using colons 2001:0DB8:0000:2F3B:02AA:00FF:FE28:9C5A

16. 16 IPv6 address syntax (4) IPv6 address in binary form 0010000000000001000011011011100000000000000000000010111100111011 0000001010101010000000001111111111111110001010001001110001011010 Divided along 16-bit boundaries 0010000000000001 0000110110111000 0000000000000000 0010111100111011 0000001010101010 0000000011111111 1111111000101000 1001110001011010 Each 16-bit block is converted to hexadecimal and delimited by using colons 2001:0DB8:0000:2F3B:02AA:00FF:FE28:9C5A Suppress leading zeros within each block 2001:DB8:0:2F3B:2AA:FF:FE28:9C5A

17. 17 Compressing zeros Typical IPv6 addresses contain long sequences of zeros A single contiguous sequence of 16-bit blocks set to 0 can be compressed to “::”

18. 18 Compressing zeros (2) Typical IPv6 addresses contain long sequences of zeros A single contiguous sequence of 16-bit blocks set to 0 can be compressed to “::” Examples FE80:0:0:0:2AA:FF:FE9A:4CA2 becomes FE80::2AA:FF:FE9A:4CA2 FF02:0:0:0:0:0:0:2 becomes FF02::2

19. 19 Compressing zeros (3) Typical IPv6 addresses contain long sequences of zeros A single contiguous sequence of 16-bit blocks set to 0 can be compressed to “::” Examples FE80:0:0:0:2AA:FF:FE9A:4CA2 becomes FE80::2AA:FF:FE9A:4CA2 FF02:0:0:0:0:0:0:2 becomes FF02::2 You cannot use zero compression to include part of a 16-bit block FF02:30:0:0:0:0:0:5 does not become FF02:3::5, but FF02:30::5

20. 20 IPv6 address prefixes Always use address/prefix-length notation Also known as CIDR notation Examples 2001:DB8:0:2F3B::/64 is a subnet prefix for a subnet 2001:DB8::/48 is an address prefix for a summarized route FF00::/8 is an address prefix for an address range

21. 21 IPv6 address prefixes (2) Always use address/prefix-length notation Also known as CIDR notation Examples 2001:DB8:0:2F3B::/64 is a subnet prefix for a subnet 2001:DB8::/48 is an address prefix for a summarized route FF00::/8 is an address prefix for an address range  ::/0 for the default route

22. 22 Types of IPv6 addresses Unicast Address of a single interface Delivery to single interface Multicast Address of a set of interfaces Delivery to all interfaces in the set Anycast Address of a set of interfaces Delivery to a single interface in the set No more broadcast addresses

23. 23 Unicast IPv6 addresses Global addresses Link-local addresses Site-local addresses Unique local addresses

24. 24 Global addresses Address scope is the whole IPv6 Internet Equivalent to public IPv4 addresses Defined in RFC 3587 Structure Global Routing Prefix Subnet ID Interface ID 64 bits Subnet ID 45 bits 001Global Routing Prefix 16 bits

25. 25 Link-local addresses Address scope is a single link Equivalent to APIPA IPv4 addresses FE80::/64 prefix Usage Single subnet, routerless configurations Neighbor Discovery processes 1111 1110 10Interface ID 10 bits64 bits 000... 000 54 bits

26. 26 Site-local addresses Address scope is a single site Equivalent to private IPv4 addresses FEC0::/10 prefix Used for intranets that are not connected to the IPv6 Internet Recently made obsolete, but supported for current implementations 1111 1110 11Interface ID 10 bits64 bits54 bits Subnet ID

27. 27 Zone IDs for link-local and site- local addresses Link-local and site-local addresses are ambiguous Multiple links (common) Multiple sites (uncommon)

28. 28 Zone IDs for link-local and site- local addresses (2) Link-local and site-local addresses are ambiguous Multiple links (common) Multiple sites (uncommon) Zone ID is used to identify a specific link or site Link-local address Zone ID is typically set to the interface index of the sending interface Site-local address Zone ID is typically 1 unless multiple sites are used

29. 29 Zone IDs for link-local and site- local addresses (3) Link-local and site-local addresses are ambiguous Multiple links (common) Multiple sites (uncommon) Zone ID is used to identify a specific link or site Link-local address Zone ID is typically set to the interface index of the sending interface Site-local address Zone ID is typically 1 unless multiple sites are used Examples ping fe80::2b0:d0ff:fee9:4143%3 tracert fec0::f282:2b0:d0ff:fee9:4143%2

30. 30 Unique local addresses Private to an organization, yet unique across all the sites of the organization FD00::/8 prefix Replacement for site-local addresses Global scope, no zone ID required 1111 110Interface ID 7 bits64 bits Global ID 40 bits Subnet ID 16 bits L

31. 31 IPv6 interface identifiers Interface identifiers are based the following items. Extended Unique Identifier (EUI)-64 address Either assigned to a network adapter card or derived from IEEE 802 (MAC) addresses A randomly generated value that changes over time A value assigned by a stateful address configuration protocol such as Dynamic Host Configuration Protocol for IPv6 (DHCPv6) A value assigned during the establishment of a Point- to-Point Protocol connection A manually configured value

32. 32 IEEE 802 addresses Company ID Extension ID u bit – Universally (=0)/Locally (=1) Administered g bit – Unicast (=0)/Group (=1) Address ccccccug cccccccc cccccccc 24 bits xxxxxxxx xxxxxxxx xxxxxxxx IEEE administered company IDManufacturer selected extension ID

33. 33 IEEE EUI-64 addresses Extended Unique Identifier Company ID Extension ID ccccccug cccccccc cccccccc 24 bits40 bits xxxxxxxx xxxxxxxx xxxxxxxx xxxxxxxx xxxxxxxx IEEE administered company IDManufacturer selected extension ID

34. 34 Mapping IEEE 802 addresses to EUI- 64 addresses ccccccug cccccccc cccccccc 24 bits xxxxxxxx xxxxxxxx xxxxxxxx ccccccug cccccccc cccccccc 24 bits xxxxxxxx xxxxxxxx xxxxxxxx 1111111111111110 0xFF0xFE IEEE administered company IDManufacturer selected extension ID 64 bits

35. 35 Obtaining interface identifiers for IPv6 addresses ccccccug cccccccc ccccccccxxxxxxxx xxxxxxxx xxxxxxxx xxxxxxxx xxxxxxxx ccccccUg cccccccc ccccccccxxxxxxxx xxxxxxxx xxxxxxxx xxxxxxxx xxxxxxxx EUI-64 Address IPv6 Interface Identifier Complement the universal/locally administered bit

36. 36 Converting IEEE 802 addresses to IPv6 interface identifiers cccccc00 cccccccc cccccccc 24 bits xxxxxxxx xxxxxxxx xxxxxxxx cccccc00 cccccccc ccccccccxxxxxxxx xxxxxxxx xxxxxxxx 1111111111111110 0xFF0xFE IEEE administered company IDManufacturer selected extension ID cccccc10 cccccccc cccccccc 64 bits 11111111 11111110 xxxxxxxx xxxxxxxx xxxxxxxx IPv6 Interface Identifier: EUI-64 Address: IEEE 802 Address:

37. 37 EUI-64 interface ID example Host A has the MAC address of 00-AA-00-3F-2A-1C 1. Convert MAC address to EUI-64 format 00-AA-00-FF-FE-3F-2A-1C

38. 38 EUI-64 interface ID example (2) Host A has the MAC address of 00-AA-00-3F-2A-1C 1. Convert MAC address to EUI-64 format 00-AA-00-FF-FE-3F-2A-1C 2. Complement the U/L bit (seventh bit of first byte) The first byte in binary form is 00000000. When the seventh bit is complemented, it becomes 00000010 (0x02). 02-AA-00-FF-FE-3F-2A-1C

39. 39 EUI-64 interface ID example (3) Host A has the MAC address of 00-AA-00-3F-2A-1C 1. Convert MAC address to EUI-64 format 00-AA-00-FF-FE-3F-2A-1C 2. Complement the U/L bit (seventh bit of first byte) The first byte in binary form is 00000000. When the seventh bit is complemented, it becomes 00000010 (0x02). 02-AA-00-FF-FE-3F-2A-1C 3. Convert to colon hexadecimal notation ::2AA:FF:FE3F:2A1C

40. 40 EUI-64 interface ID example (4) Host A has the MAC address of 00-AA-00-3F-2A-1C 1. Convert MAC address to EUI-64 format 00-AA-00-FF-FE-3F-2A-1C 2. Complement the U/L bit (seventh bit of first byte) The first byte in binary form is 00000000. When the seventh bit is complemented, it becomes 00000010 (0x02). 02-AA-00-FF-FE-3F-2A-1C 3. Convert to colon hexadecimal notation ::2AA:FF:FE3F:2A1C The link-local address for a node with the MAC address of 00-AA-00-3F-2A-1C is FE80::2AA:FF:FE3F:2A1C

41. 41 How to read an IPv6 unicast address 128-bit address is eight 16-bit blocks.

42. 42 How to read an IPv6 unicast address (2) 128-bit address is eight 16-bit blocks. The first four blocks identify the network segment (subnet). The first block identifies the type of unicast address. Starts with FE80: link-local address Starts with FEC-FEF: site-local address Starts with 2 or 3: global address Starts with FD: unique local address

43. 43 How to read an IPv6 unicast address (3) 128-bit address is eight 16-bit blocks. The first four blocks identify the network segment (subnet). The first block identifies the type of unicast address. Starts with FE80: link-local address Starts with FEC-FEF: site-local address Starts with 2 or 3: global address Starts with FD: unique local address The last four blocks identify the interface on the network segment.

44. 44 How to read an IPv6 unicast address (4) Example 1: 2001:DB8:0:2F3B:2AA:FF:FE28:9C5A 2001:DB8:0:2F3B::/64 identifies the network segment ::2AA:FF:FE28:9C5A identifies the interface

45. 45 How to read an IPv6 unicast address (5) Example 1: 2001:DB8:0:2F3B:2AA:FF:FE28:9C5A 2001:DB8:0:2F3B::/64 identifies the network segment ::2AA:FF:FE28:9C5A identifies the interface Example 2: FEC0::12:2AA:FF:FE9A:21AC FEC0:0:0:12::/64 identifies the network segment ::2AA:FF:FE9A:21AC identifies the interface

46. 46 Multicast IPv6 addresses FlagsScope Defined multicast addresses FF02::1 (Link-local scope all-nodes address) FF02::2 (Link-local scope all-routers address) 1111 Group ID 8 bits32 bits Flags 4 bits Scope 4 bits80 bits 000 … 000

47. 47 Solicited-node address Used for address resolution Example For FE80::2AA:FF:FE28:9C5A, the corresponding solicited-node address is FF02::1:FF28:9C5A Interface ID 64 bits Unicast prefix 64 bits FF02: 24 bits :1:FF0:0:0:0

48. 48 Mapping IPv6 multicast addresses to Ethernet addresses 1111 Group ID 8 bits32 bits Flags 4 bits Scope 4 bits80 bits 000 … 000 33-33- Ethernet MAC address: Examples For FF02::1, the corresponding Ethernet MAC address is 33-33-00- 00-00-01 For solicited-node address FF02::1:FF28:9C5A, the corresponding Ethernet MAC address is 33-33-FF-28-9C-5A

49. 49 DNS support Name to address records AAAA record type, equivalent to IPv4 A record Example record host1.microsoft.com IN AAAA FEC0::1:2AA:FF:FE3F:2A1C

50. 50 DNS support (2) Name to address records AAAA record type, equivalent to IPv4 A record Example record host1.microsoft.com IN AAAA FEC0::1:2AA:FF:FE3F:2A1C Address to name records New reverse domain called IP6.ARPA Example record FEC0::1:2AA:FF:FE3F:2A1C is FEC0:0000:0000:0001:02AA:00FF:FE3F:2A1C C.1.A.2.F.3.E.F.F.F.0.0.A.A.2.0.1.0.0.0.0.0.0.0.0.0.0.0.0.C.E.F. IP6.ARPA. IN PTR host1.microsoft.com

51. 51 DNS support (3) Name to address records AAAA record type, equivalent to IPv4 A record Example record host1.microsoft.com IN AAAA FEC0::1:2AA:FF:FE3F:2A1C Address to name records New reverse domain called IP6.ARPA Example record FEC0::1:2AA:FF:FE3F:2A1C is FEC0:0000:0000:0001:02AA:00FF:FE3F:2A1C C.1.A.2.F.3.E.F.F.F.0.0.A.A.2.0.1.0.0.0.0.0.0.0.0.0.0.0.0.C.E.F. IP6.ARPA. IN PTR host1.microsoft.com DNS dynamic update Host registers global, site-local, and unique local addresses

52. 52 Source and destination address selection A typical IPv6 host has multiple IPv6 addresses assigned to multiple interfaces. When multiple IPv6 addresses are returned during DNS name resolution, IPv6 uses the following algorithms. A source address selection algorithm to select the best source address to use with a destination address A destination address selection algorithm to sort the list of possible destination addresses in order of preference

53. 53 IPv4 addresses and IPv6 equivalents IPv4 AddressIPv6 Address Internet address classesNot applicable Multicast addresses (224.0.0.0/4)IPv6 multicast addresses (FF00::/8) Broadcast addressesNot applicable Unspecified address is 0.0.0.0Unspecified address is :: Loopback address is 127.0.0.1Loopback address is ::1 Public IP addressesGlobal addresses Private IP addressesSite-local addresses (FEC0::/10) APIPA addresses (169.254.0.0/16)Link-local addresses (FE80::/64) Syntax: Dotted decimal notationColon hexadecimal notation Masks: Dotted decimal or prefix lengthPrefix length notation only DNS forward: A resource recordAAAA resource records DNS reverse: IN-ADDR.ARPA domainIP6.ARPA domain

54. 54 IPv6 header Structure of an IPv6 packet IPv6 header IPv6 extension headers

55. 55 Structure of an IPv6 packet IPv6 Header Upper Layer Protocol Data Unit Payload IPv6 Packet Extension Headers

56. 56 IPv4 header Version Internet Header Length Type of Service Total Length Identification Flags Fragment Offset Time to Live Protocol Header Checksum Source Address Destination Address Options...

57. 57 IPv6 header Version Traffic Class Flow Label Payload Length Next Header Hop Limit Source Address Destination Address

58. 58 Comparing the IPv4 and IPv6 headers IPv4 Header FieldChange in IPv6 VersionNew value of 6 Internet Header LengthRemoved Type of ServiceTraffic Class field Total LengthPayload Length field IdentificationRemoved to Fragment extension header Fragmentation FlagsRemoved to Fragment extension header Fragment OffsetRemoved to Fragment extension header Time to LiveHop Limit field ProtocolNext Header field Header ChecksumRemoved Source AddressSame, new 128-bit length Destination AddressSame, new 128-bit length OptionsRemoved to extension headers

59. 59 IPv6 extension headers IPv6 Header Next Header = 6 (TCP) TCP Segment

60. 60 IPv6 extension headers (2) IPv6 Header Next Header = 6 (TCP) TCP SegmentIPv6 Header Next Header = 43 (Routing) TCP SegmentRouting Header Next Header = 6 (TCP)

61. 61 IPv6 extension headers (3) IPv6 Header Next Header = 6 (TCP) TCP SegmentIPv6 Header Next Header = 43 (Routing) TCP SegmentRouting Header Next Header = 6 (TCP) Authentication Header Next Header = 6 (TCP) IPv6 Header Next Header = 43 (Routing) Routing Header Next Header = 51 (AH) TCP Segment

62. 62 Extension headers order 1.Hop-by-Hop Options header 2.Destination Options header (for intermediate destinations when the Routing header is present) 3.Routing header 4.Fragment header 5.Authentication header (AH) 6.Encapsulating Security Payload (ESP) header 7.Destination Options header (for the final destination)

63. 63 Extension headers order (2) 1.Hop-by-Hop Options header 2.Destination Options header (for intermediate destinations when the Routing header is present) 3.Routing header 4.Fragment header 5.Authentication header (AH) 6.Encapsulating Security Payload (ESP) header 7.Destination Options header (for the final destination) Intermediate destinations Final destination

64. 64 ICMPv6 and MLD Internet Control Message Protocol for IPv6 (ICMPv6) overview ICMPv6 messages Path Maximum Transfer Unit (MTU) discovery Multicast Listener Discovery (MLD) overview MLD messages

65. 65 Overview of ICMPv6 Updated version of the Internet Control Message Protocol (ICMP) for IPv6 Reports delivery or forwarding errors Provides simple echo service for troubleshooting Provides a message format for Multicast Listener Discovery (MLD) Neighbor Discovery (ND)

66. 66 Types of ICMPv6 messages Error messages Report errors in the forwarding or delivery of IPv6 packets by either the destination node or an intermediate router Informational messages Provide diagnostic functions and additional host functionality

67. 67 ICMPv6 error messages Destination Unreachable No matching route Communication prohibited by policy Destination address is beyond the scope of the source address The destination address is unreachable The destination port was unreachable Packet Too Big Time Exceeded Parameter Problem

68. 68 ICMPv6 informational messages Echo Request Echo Reply Additional messages are used for MLD and ND

69. 69 Comparing ICMPv4 and ICMPv6 messages Common ICMPv4 Message Destination Unreachable- Network unreachable Destination Unreachable-Protocol unreachable Destination Unreachable-Port unreachable Destination Unreachable-Fragmentation needed and DF set Time Exceeded-TTL expired Parameter Problem Redirect ICMPv6 Equivalent Destination Unreachable-No route to destination Parameter Problem-Unrecognized Next Header field Destination Unreachable-Port unreachable Packet Too Big Time Exceeded-Hop Limit exceeded Parameter Problem Neighbor Discovery Redirect message

70. 70 Path MTU discovery 1.The sending node assumes that the path MTU is the link MTU of the interface on which the traffic is being forwarded. 2.The sending node sends IPv6 packets at the link MTU size. 3.A router that is unable to forward the packet sends an ICMPv6 Packet Too Big message back to the sending node. This message contains the link MTU of the link on which the forwarding failed. 4.The sending node resets the path MTU to the value of the MTU field in the ICMPv6 Packet Too Big message.

71. 71 Multicast Listener Discovery (MLD) overview IPv6 equivalent of Internet Group Management Protocol version 2 (IGMPv2) for IPv4 Enables routers to discover the set of multicast addresses for which there are listening nodes for each attached interface

72. 72 MLD messages Multicast Listener Query Multicast router queries network to determine membership in a host group Multicast Listener Report Host declares membership in a host group Multicast Listener Done Host declares that there might not be any more members of a host group on a subnet

73. 73 Neighbor Discovery Overview Neighbor Discovery (ND) messages Neighbor Discovery options Neighbor Discovery processes Address resolution Router discovery Neighbor unreachability detection Redirect Host sending algorithm

74. 74 Neighbor Discovery overview Set of messages and processes that determine relationships between neighboring nodes Replaces ARP, ICMPv4 Router Discovery, and ICMPv4 Redirect

75. 75 Neighbor Discovery overview (2) Set of messages and processes that determine relationships between neighboring nodes Replaces ARP, ICMPv4 Router Discovery, and ICMPv4 Redirect Used by hosts Discover neighboring routers Perform stateless address autoconfiguration

76. 76 Neighbor Discovery overview (3) Set of messages and processes that determine relationships between neighboring nodes Replaces ARP, ICMPv4 Router Discovery, and ICMPv4 Redirect Used by hosts Discover neighboring routers Perform stateless address autoconfiguration Used by routers Advertise their presence, host configuration parameters, and on- link prefixes Inform hosts of a better next-hop address

77. 77 Neighbor Discovery overview (4) Set of messages and processes that determine relationships between neighboring nodes Replaces ARP, ICMPv4 Router Discovery, and ICMPv4 Redirect Used by hosts Discover neighboring routers Perform stateless address autoconfiguration Used by routers Advertise their presence, host configuration parameters, and on- link prefixes Inform hosts of a better next-hop address Used by nodes For address resolution Determine neighbor reachability

78. 78 Neighbor Discovery message format ICMPv6 message structure and ICMPv6 types 133 through 137 To guarantee local link traffic, all ND messages are sent with a hop limit of 255 IPv6 Header Next Header = 58 (ICMPv6) Neighbor Discovery Message Options Neighbor Discovery Message Header Neighbor Discovery Message

79. 79 Neighbor Discovery messages Router Solicitation Router Advertisement Neighbor Solicitation Neighbor Advertisement Redirect

80. 80 Neighbor Discovery options Source Link-Layer Address Target Link-Layer Address Prefix Information MTU Route Information Redirected Header

81. 81 Host data structures Neighbor cache Stores the on-link IP address of a neighbor, its corresponding link-layer address, and the neighbor’s reachability state Equivalent to the ARP cache in IPv4 Destination cache Stores information about forwarding or next-hop IPv6 addresses for destinations to which traffic has recently been sent

82. 82 Host data structures (2) Prefix list Lists on-link prefixes Default router list Lists IP addresses corresponding to on-link routers that send Router Advertisement messages and are eligible to be default routers

83. 83 Neighbor Discovery processes ND provides message exchanges for the following processes. Address resolution (including duplicate address detection) Router discovery (including prefix and parameter discovery) Neighbor unreachability detection Redirect function

84. 84 Address resolution Resolves the link-layer address of the on- link next-hop address Exchange of messages Multicast Neighbor Solicitation message Unicast Neighbor Advertisement message Both nodes update their neighbor caches Link-layer unicast traffic can now be sent

85. 85 Address resolution example Part 1 Host B Host A MAC: 00-AA-00-11-11-11 IP: FE80::2AA:FF:FE11:1111 MAC: 00-AA-00-22-22-22 IP: FE80::2AA:FF:FE22:2222

86. 86 Address resolution example (2) Part 1 Host B Host A  Send multicast Neighbor Solicitation Neighbor Solicitation MAC: 00-AA-00-11-11-11 IP: FE80::2AA:FF:FE11:1111 MAC: 00-AA-00-22-22-22 IP: FE80::2AA:FF:FE22:2222

87. 87 Address resolution example (3) Part 1 Host B Host A  Send multicast Neighbor Solicitation Neighbor Solicitation Ethernet Header Dest MAC is 33-33-FF-22-22-22 IPv6 Header Source Address is FE80::2AA:FF:FE11:1111 Destination Address is FF02::1:FF22:2222 Hop limit is 255 Neighbor Solicitation Header Target Address is FE80::2AA:FF:FE22:2222 Neighbor Discovery Option Source Link-Layer Address MAC: 00-AA-00-11-11-11 IP: FE80::2AA:FF:FE11:1111 MAC: 00-AA-00-22-22-22 IP: FE80::2AA:FF:FE22:2222

88. 88 Host B Host A  Send multicast Neighbor Solicitation Neighbor Solicitation Ethernet Header Dest MAC is 33-33-FF-22-22-22 IPv6 Header Source Address is FE80::2AA:FF:FE11:1111 Destination Address is FF02::1:FF22:2222 Hop limit is 255 Neighbor Solicitation Header Target Address is FE80::2AA:FF:FE22:2222 Neighbor Discovery Option Source Link-Layer Address MAC: 00-AA-00-11-11-11 IP: FE80::2AA:FF:FE11:1111 MAC: 00-AA-00-22-22-22 IP: FE80::2AA:FF:FE22:2222 Mapping the Target Address to the solicited- node multicast address Address resolution example (4) Part 1

89. 89 Host B Host A  Send multicast Neighbor Solicitation Neighbor Solicitation Ethernet Header Dest MAC is 33-33-FF-22-22-22 IPv6 Header Source Address is FE80::2AA:FF:FE11:1111 Destination Address is FF02::1:FF22:2222 Hop limit is 255 Neighbor Solicitation Header Target Address is FE80::2AA:FF:FE22:2222 Neighbor Discovery Option Source Link-Layer Address MAC: 00-AA-00-11-11-11 IP: FE80::2AA:FF:FE11:1111 MAC: 00-AA-00-22-22-22 IP: FE80::2AA:FF:FE22:2222 Mapping the IPv6 multicast address to the Ethernet multicast MAC address Address resolution example (5) Part 1

90. 90 Host B Host A ‚ Send unicast Neighbor Advertisement Neighbor Advertisement MAC: 00-AA-00-11-11-11 IP: FE80::2AA:FF:FE11:1111 MAC: 00-AA-00-22-22-22 IP: FE80::2AA:FF:FE22:2222 Address resolution example (6) Part 2

91. 91 Host B Host A ‚ Send unicast Neighbor Advertisement Neighbor Advertisement Ethernet Header Dest MAC is 00-AA-00-11-11-11 IPv6 Header Source Address is FE80::2AA:FF:FE22:2222 Destination Address is FE80::2AA:FF:FE11:1111 Hop limit is 255 Neighbor Advertisement Header Target Address is FE80::2AA:FF:FE22:2222 Neighbor Discovery Option Target Link-Layer Address MAC: 00-AA-00-11-11-11 IP: FE80::2AA:FF:FE11:1111 MAC: 00-AA-00-22-22-22 IP: FE80::2AA:FF:FE22:2222 Address resolution example (7) Part 2

92. 92 Duplicate address detection Duplicate address detection uses a Neighbor Solicitation message to detect a duplicate unicast address. The Target Address field in the Neighbor Solicitation message is set to the IPv6 address for which duplication is being detected. The Source Address is set to the unspecified address (::). For a duplicate address, the defending node replies with a multicast Neighbor Advertisement. The Destination Address is set to the link-local scope all-nodes multicast address (FF02::1).

93. 93 Router discovery Hosts use router discovery to determine the following items The set of routers on the local link Default value of Hop Limit field Use of stateful address protocol Reachability and retransmission timers Subnet prefixes for the link MTU of the local link Specific routes

94. 94 Router discovery example Part 1 Router 1 Host A MAC: 00-AA-00-11-11-11 IP: FE80::2AA:FF:FE11:1111 MAC: 00-AA-00-22-22-22 IP: FE80::2AA:FF:FE22:2222

95. 95 Router discovery example (2) Part 1 Router 1 Host A  Send multicast Router Solicitation Router Solicitation MAC: 00-AA-00-11-11-11 IP: FE80::2AA:FF:FE11:1111 MAC: 00-AA-00-22-22-22 IP: FE80::2AA:FF:FE22:2222

96. 96 Router discovery example (3) Part 1 Router 1 Host A  Send multicast Router Solicitation Router Solicitation Ethernet Header Dest MAC is 33-33-00-00-00-02 IPv6 Header Source Address is FE80::2AA:FF:FE11:1111 Destination Address is FF02::2 Hop limit is 255 Neighbor Discovery Option Source Link-Layer Address MAC: 00-AA-00-11-11-11 IP: FE80::2AA:FF:FE11:1111 MAC: 00-AA-00-22-22-22 IP: FE80::2AA:FF:FE22:2222

97. 97 Host A ‚ Send unicast Router Advertisement Router Advertisement MAC: 00-AA-00-11-11-11 IP: FE80::2AA:FF:FE11:1111 MAC: 00-AA-00-22-22-22 IP: FE80::2AA:FF:FE22:2222 Router 1 Router discovery example (4) Part 2

98. 98 Host A ‚ Send unicast Router Advertisement Router Advertisement Ethernet Header Dest MAC is 00-AA-00-11-11-11 IPv6 Header Source Address is FE80::2AA:FF:FE22:2222 Destination Address is FE80::2AA:FF:FE11:1111 Hop limit is 255 Router Advertisement Header Cur Hop Limit, Flags, Router/Reachable/Retrans Neighbor Discovery Options Source Link-Layer Address MTU Prefix Information MAC: 00-AA-00-11-11-11 IP: FE80::2AA:FF:FE11:1111 MAC: 00-AA-00-22-22-22 IP: FE80::2AA:FF:FE22:2222 Router 1 Router discovery example (5) Part 2

99. 99 Neighbor unreachability detection Reachability is the ability to send an IPv6 packet to a neighboring node and have that packet be successfully received and processed. Reachability is determined by the following items. Upper layer protocols Receipt of a Neighbor Advertisement message in response to a unicast Neighbor Solicitation message Neighbor unreachability detection detects symmetric reachability.

100. 100 Redirect function Redirect informs originating hosts of a better first-hop neighbor to which traffic should be forwarded for a specific destination Two instances A router informs an originating host of the IP address of a router available on the local link that is “closer” to the destination. A router informs an originating host that the destination is a neighbor—that is, that the destination is on the same link as the originating host. A redirect message contains the best first-hop link-layer address information Redirect messages are only sent by the first router in the path between the originating host and the destination

101. 101 Redirect example Part 1 Host A Ethernet Header Dest MAC is 00-AA-00-22-22-22 IPv6 Header Source Address is FEC0::1:2AA:FF:FE11:1111 Destination Address is FEC0::2:2AA:FF:FE99:9999 MAC: 00-AA-00-22-22-22 IP: FEC0::1:2AA:FF:FE22:2222 FE80::2AA:FF:FE22:2222 Router 2Router 3 Unicast Packet  Send unicast packet MAC: 00-AA-00-33-33-33 IP: FEC0::1:2AA:FF:FE33:3333 FE80::2AA:FF:FE33:3333 MAC: 00-AA-00-11-11-11 IP: FEC0::1:2AA:FF:FE11:1111 FE80::2AA:FF:FE11:1111

102. 102 Redirect example (2) Part 2 Host A Ethernet Header Dest MAC is 00-AA-00-33-33-33 IPv6 Header Source Address is FEC0::1:2AA:FF:FE11:1111 Destination Address is FEC0::2:2AA:FF:FE99:9999 MAC: 00-AA-00-11-11-11 IP: FEC0::1:2AA:FF:FE11:1111 FE80::2AA:FF:FE11:1111 MAC: 00-AA-00-22-22-22 IP: FEC0::1:2AA:FF:FE22:2222 FE80::2AA:FF:FE22:2222 Router 2Router 3 MAC: 00-AA-00-33-33-33 IP: FEC0::1:2AA:FF:FE33:3333 FE80::2AA:FF:FE33:3333 Unicast Packet ‚ Forward unicast packet

103. 103 Redirect example (3) Part 3 Host A  Send unicast Redirect Redirect Ethernet Header Dest MAC is 00-AA-00-11-11-11 IPv6 Header Source Address is FE80::2AA:FF:FE22:2222 Destination Address is FEC0::1:2AA:FF:FE11:1111 Hop limit is 255 Redirect Header Target Address is FE80::2AA:FF:FE33:3333 Destination Address is FEC0::2:2AA:FF:FE99:9999 Neighbor Discovery Options Target Link-Layer Address Redirected Header Router 2Router 3 MAC: 00-AA-00-33-33-33 IP: FEC0::1:2AA:FF:FE33:3333 FE80::2AA:FF:FE33:3333 MAC: 00-AA-00-11-11-11 IP: FEC0::1:2AA:FF:FE11:1111 FE80::2AA:FF:FE11:1111 MAC: 00-AA-00-22-22-22 IP: FEC0::1:2AA:FF:FE22:2222 FE80::2AA:FF:FE22:2222

104. 104 Host sending algorithm Determine the next-hop address for the destination. Check the destination cache. If the destination address matches a prefix in the prefix list, the next-hop address is the destination address. If the destination address does not match a prefix in the prefix list, the next-hop address is the default router address. Determine the link-layer address for the next-hop address. Check the neighbor cache. Use address resolution to obtain the link-layer address for the next-hop address. Send the packet using the link-layer address of the next- hop address.

105. 105 IPv4 neighbor functions and IPv6 equivalents IPv4 Neighbor FunctionIPv6 Neighbor Function ARP Request messageNeighbor Solicitation message ARP Reply messageNeighbor Advertisement message ARP cacheNeighbor cache Gratuitous ARPDuplicate Address Detection Router Solicitation message (optional)Router Solicitation message (required) Router Advertisement message (optional)Router Advertisement message (required) Redirect messageRedirect message

106. 106 Address autoconfiguration Overview Autoconfigured address states Types of address autoconfiguration Address autoconfiguration process

107. 107 Address autoconfiguration overview IPv6 interfaces can automatically configure themselves. Even without a stateful configuration protocol such as Dynamic Host Configuration Protocol for IPv6 (DHCPv6) By default, link-local address for each interface By using router discovery, a host can determine Additional addresses Router addresses Other configuration parameters

108. 108 Autoconfigured address states Tentative The address is being verified as unique Valid An address from which unicast traffic can be sent and received Preferred state An address for which uniqueness has been verified, unrestricted use Deprecated state An address that is still valid, but is discouraged for new communication Invalid An address for which a node can no longer send or receive unicast traffic

109. 109 Autoconfigured address states (2) TentativePreferredDeprecatedInvalid Preferred Lifetime Valid Valid Lifetime time

110. 110 Types of autoconfiguration 1.Stateless Receipt of Router Advertisement messages that have one or more Prefix Information options 2.Stateful Use of a stateful address configuration protocol such as DHCPv6 3.Both Receipt of Router Advertisement messages and stateful configuration protocol For all types, a link-local address is always configured

111. 111 Address autoconfiguration process Configure link-local address. Perform duplicate address detection Perform router discovery. Use Router Advertisement message contents to determine the following items. Configuration parameters Stateless addresses and on-link prefixes For stateless addresses, perform duplicate address detection Whether to use stateful address configuration Specific routes

112. 112 IPv6 resources IPv6 Web site http://www.microsoft.com/ipv6 “Introduction to Internet Protocol version 6” white paper http://www.microsoft.com/technet/ itsolutions/network/ipv6/introipv6.mspx http://www.microsoft.com/technet/ itsolutions/network/ipv6/introipv6.mspx

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