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IP Version 6

IP Version 6. IPv6 Overview & The IPv6 Header Format. 1.The main causes for change from IPv4 to IPv6 Dramatically increase the number of IP addresses IP Address Exhaustion The global internet is growing exponentially, with the size more than doubling annually.

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IP Version 6

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  1. IP Version 6 SCUT DT&P Labs

  2. IPv6 Overview & The IPv6 Header Format SCUT DT&P Labs

  3. 1.The main causes for change from IPv4 to IPv6 • Dramatically increase the number of IP addresses • IP Address Exhaustion • The global internet is growing exponentially, with the size more than doubling annually. • The estimates were that the IP address space would be exhausted at some point between 2005 and 2011. SCUT DT&P Labs

  4. 1.The main cause for change from IPv4 to IPv6 (2) Provide better support for real-time applications Traffic priority For example, applications that deliver audio and video need to deliver data at regular intervals. To keep such information flowing through the Internet without disruption, IP must avoid changing routes frequently. SCUT DT&P Labs

  5. 1.The main cause for change from IPv4 to IPv6 (3) Security features The security implemented in IPv6 guarantees that that a packet is actually coming from the host indicated in its source address, unlike in IPv4 where the packet could be coming from a host other than that indicated in the source -this is known as “spoofing”. SCUT DT&P Labs

  6. 2. New significant features of IPv6 (1)Address size: 128-bit addresses It is said to be sufficient for the next 30 years. There are enough addresses supported by IPv6 to provide an order of 6×1023 unique addresses per square meter of the surface of the earth. SCUT DT&P Labs

  7. 2. New significant features of IPv6 (2) Improved option mechanism Simplifies and speeds up router processing of IPv6 packets. IPv6 options are placed in separate optional headers that are located between the IPv6 header and the transport layer header. Most of these optional headers are not examined or processed by any router on the packet’s path. SCUT DT&P Labs

  8. 2. New significant features of IPv6 (3) Address autoconfiguration Dynamic assignment of IPv6 addresses • A version of DHCP has been developed for IPv6. • It maintains static tables that determine which addresses are assigned to a new or moved stations. SCUT DT&P Labs

  9. 2. New significant features of IPv6 • Stateless autoconfiguration makes it possible for devices to configure their own addresses with the help of a local IPv6 router. SCUT DT&P Labs

  10. 2. New significant features of IPv6 (4) Improving multicast routing support. (5) Built-in authentication and encryption. SCUT DT&P Labs

  11. 3. The IPv6 Packet Format 40 bytes Optional Base Header Extension Header 1 Extension Header N Data area …... The IPv6 datagram begins with a base header, which is followed by zero or more extension headers, followed by data. The only header required is that of the IPv6 header. This is of fixed size with a length of 40 octets compared to 20 octets for the mandatory portion of the IPv4 header. SCUT DT&P Labs

  12. Version Priority Flow Label Payload Length Hop Limit Next Header Source Address Destination Address 3. The IPv6 Header Format 0 4 8 16 24 31 10 x 32 bits = 40 octets SCUT DT&P Labs

  13. 3. The IPv6 Header Format • The IPv6 header has a fixed length of 40 octets, consisting of eight fields: • Version (4 bits): IP version number; the value is 6. • Priority (4 bits): Priority value of each packet specifies the traffic class. • Values between 0 and 7 are defined for congestion controlled traffic (data) and between 8 and 15 for non-congestion controlled traffic (video and audio). SCUT DT&P Labs

  14. 3. The IPv6 Header Format • Flow Label (24 bits): used by applications that require a performance guarantee to specify the path. • The IPv6 standard defines a flow as a sequence of packets sent from a particular source to a particular destination. • A flow is uniquely identified by the combination of source address and a 24-bit flow label. Thus all packets that are to be part of the same flow are assigned the same flow label by the source. SCUT DT&P Labs

  15. 3. The IPv6 Header Format • Next Header (8 bits): identifies the type of header immediately following the IPv6 header. • A TCP/UDP header (upper layer protocol) or • A IPv6 optional header (extension header). • Payload Length (16 bits): specifies the size of the data being carried. SCUT DT&P Labs

  16. 3. The IPv6 Header Format • Hop Limit (8 bits): the remaining number of hops for this packet. • The hop limit is set to a desired maximum value by the source and decremented by 1 by each node that forwards this packet. • The packet is discarded if the hop limit is decremented to zero. SCUT DT&P Labs

  17. 3. The IPv6 Header Format • Source Address (128 bits): the address of the sender of the packet. • Destination Address (128 bits): address of the intended recipient of packet. • Although the IPv6 Header is longer than that of the IPv4 header, it contains fewerfields. Thus routers have less processing to do per header, which should speed up routing. SCUT DT&P Labs

  18. 3. The IPv6 Header Format The fields in IPv4 headerthat no longer appear in the IPv6 header: Type of Service, its function can be replaced by the “Flow Labels”; Identification, Fragmentation Flags and Fragment Offset. Higher-level protocols tend to avoid the fragmentation and an extension can be employed if Fragmentation is needed. Header Checksum. IPv6’s optional authentication header that can also be used to ensure integrity. SCUT DT&P Labs

  19. 4. IPv6 Extension Header Extension header Description Hop-by-hop options Miscellaneous information for routers Destination options -1 Information for 1st destination Routing Full or partial route to follow Fragmentation Management of datagram fragments Authentication Verification of the sender’s identity Encrypted security payload Information about the encrypted contents Destination options -2 Additional information for the final destination only Note: the extension header order SCUT DT&P Labs

  20. 4. IPv6 Extension Header vers priority Flow label Payload length nxt h:0 Hop limit Source address Destination address The type of extension header (with exception of 59: no next header) is defined in the “Next Header”. nxt h:43 h length Hop-by-hop options nxt h: 6 h length Routing information TCP header and data SCUT DT&P Labs

  21. 4. IPv6 Extension Header • Hop-by-hop Options Header: • defines special options that require hop-by-hop processing. • It must immediately follow the IPv6 header if present and is defined by the special value 0 in the Next Header field of the IPv6 basic header. • The header contains the different length options with Type-Length-Value format. SCUT DT&P Labs

  22. 4. IPv6 Extension Header Hop-by-hop Options Header Type-Length-Value format type length value xx y zzzzz Type: xx: indicate how an IPv6 node that dose not recognize the option should treat it: skip, discard, … Y: if set, indicate that the value of the option may change in rout and the field is excluded from any integrity calculation performed on the packet. SCUT DT&P Labs

  23. 4. IPv6 Extension Header Hop-by-hop Options Header zzzzz: define the option: Pad1: A X’00 byte used for padding a single byte; PadN: N X’00 bytes used for padding, N is given in the field of the length byte. The padding is used to retain 8-byte alignment for subsequent headers to make processing header more efficient. SCUT DT&P Labs

  24. 4. IPv6 Extension Header Example1 xx y zzzzz= 194: the hop-by-hop header is the Jumbo Payload Length. This option is used to indicate a packet that has a payload size in excess of 65,535 byte. Type:194 Len.: 4 Jumbo Payload Length:0~4,294,967,296 SCUT DT&P Labs

  25. 4. IPv6 Extension Header Example2 xx y zzzzz= 5: the hop-by-hop header is the Router Alert. This option is used to indicate a Router Alert information. Type:5 Len.: 2 Router Alert: 0~65,535 Different number implies different alert to the routers. SCUT DT&P Labs

  26. 4. IPv6 Extension Header • Destination Option Header -1: • Contains optional information to be examined by the first destination listed in the IPv6 address field. • This header can also be read by a subsequent destination listed in the source routing header address fields. SCUT DT&P Labs

  27. 4. IPv6 Extension Header • Destination Options Header -2: • Contains optional information to be examined only by the final destination node. • Currently, only the Pad1 and PadN types of option are specified for the Destination Options Header. SCUT DT&P Labs

  28. Routing Header: 4. IPv6 Extension Header Type: 0 The header allows a source node to specify a list of IP addresses that dictate what path a packet will traverse. nxt h h length Type:0 Addrs left reserved Address [0] Address [n-1] SCUT DT&P Labs

  29. Routing Header: 4. IPv6 Extension Header Other type The generic routing header. nxt h h length Type Seg. left Type-specific Data SCUT DT&P Labs

  30. 4. IPv6 Extension Header Routing Header Addresser/Segment Left: The number of intermediate nodes still to be visited on route to the final destination. The field of a packet is decreased by one while it passes through a router. SCUT DT&P Labs

  31. 4. IPv6 Extension Header • Fragment Header: • contains fragmentation and reassemble information. nxt h reserved frag. offset res M Fragment identification Fragment Offset (13-bit): it indicates the data that follows relative (in 8-byte units) to the start of the original data before is was fragmented. SCUT DT&P Labs

  32. 4. IPv6 Extension Header Fragment Header Res (2-bit): reserved field. M (more flag): M = 0: the last fragment; M = 1: not the last fragment. Fragment Identification: an unambiguous identifier used to identify fragments of the same datagram. Keep same value for a divided packet. SCUT DT&P Labs

  33. 4. IPv6 Extension Header • Authentication Header: provides packet integrity and authentication. • Encapsulated Security Payload Header (ESP): Provides privacy. All data following the ESP header is encrypted. • ESP provides encryption at the network layer, making it available to all applications in a highly standardised fashion. SCUT DT&P Labs

  34. 4. IPv6 Extension Header Encapsulated Security Payload Header Two modes to provide confidentiality: Transport mode ESP In this mode only the payload is encrypted. The IP header and IP options are unencrypted and are used for routing the packet. Unencrypted Encrypted IPv6 Header Extension Headers Transport Header and Payload ESP Header SCUT DT&P Labs

  35. IPv6 Header Extension Headers IPv6 Header Extension Headers ESP Header 4. IPv6 Extension Header Encapsulated Security Payload Header Tunnel mode ESP In this mode, the original IP datagram and header are encrypted. Tunnel Mode Unencrypted Encrypted Transport Header and Payload SCUT DT&P Labs

  36. 5. IPv6 Addressing IPv6 Colon Hexadecimal Notation To help reduce the number of characters in an address, the designers of IPv6 propose using a more compact syntactic form known as hexadecimal notation; Each group of 16 bits is written in hexadecimal with a colon separating groups; For example: 69DC:8864:FFFF:FFFF:0:1280:8C0A:FFFF SCUT DT&P Labs

  37. 5. IPv6 Addressing • IPv6 Colon Hexadecimal Notation • To shorten the notation of addresses, leading zeroes in any of the groups can be omitted, for example: FE80:0000:0000:0000:0001:0800:23E7:F5DB FE80:0:0:0:1:800:23E7:F5DB • A group of all zeroes, or consecutive groups of all zeroes, can be substituted by a double colon: FE80:0:0:0:1:800:23E7:F5DB FE80::1:800:23E7:F5DB The double colon shortcut can be used only once in the notation of an IPv6 address. SCUT DT&P Labs

  38. 5. IPv6 Addressing • Like IPv4, IPv6 assigns a unique address for each connection between a computer and a physical network. There are three types of IPv6 addresses: • Unicast • Multicast • Anycast . SCUT DT&P Labs

  39. (1) Unicast Address • A unicast address is an identifier assigned to a single interface; • The address corresponds to a single computer; • Special- purpose unicast addresses: • Loopback address ( ::1 ); It is assigned to a virtual interface over which a host can send packets only to itself; (IPv4: 127.0.0.1) • Unspecified address ( :: ); It is used as a source address by a host while performing autoconfiguration; (IPv4: 0.0.0.0) 5. IPv6 Addressing SCUT DT&P Labs

  40. IPv4-compatible address ( ::< IPv4_address > ): They are used when IPv6 traffic needs to be tunneled across existing IPv4 networks. IP-mapped address ( ::FFFF:< IPv4_address >): Addresses of this kind are used when an IPv6 host needs to communicate with an IPv4 host. Link-local address Addresses of this kind can be used only on the physical network that’s interface is attached to. Site-local address Addresses of this kind cannot be routed into the Internet. (IPv4 private addresses) 5. IPv6 Addressing SCUT DT&P Labs

  41. 5. IPv6 Addressing Global Uincast Address Format: The format is expected to become the predominant format used for IPv6 nodes connected to the Internet. Three sections of the address format: Public Topology: It is for providers and exchanges that provide public Internet transit services. Site Topology: It is local to an organization that does not provide public transit service to nodes outside of the site. Interface Identifiers: These identify interfaces on links. SCUT DT&P Labs

  42. Global Uincast Address Format 0 3 16 24 48 64 127 5. IPv6 Addressing FP TAL ID RES NLA ID SLA ID Interface ID Public Topology Site Interface Identifier Topology The field definition FP: Format Prefix (001) TLA ID: Top-Level Aggregation Identifier ( 13-bit): The top level in the routing hierarchy. RES: Reserved for future use (8-bit). SCUT DT&P Labs

  43. 5. IPv6 Addressing Global Uincast Address Format NLA IDNext-Level Aggregation Identifier (24-bit): It is used to create the second addressing hierarchy and to identify sites. SLA ID Site-Level Aggregation Identifier (16-bit): It is used to create a local addressing hierarchy. SCUT DT&P Labs

  44. (2) Multicast Address A multicast address is an identifier assigned to a set of interfaces on multicast (broadcast) hosts; 0 8 16 127 5. IPv6 Addressing FP Flags Scope Group ID FP Format Prefix: 1111 1111. Flags: (only the low-order bit being defined) 0000: Permanent address assigned by a numbering authority. 0001: Transient address. SCUT DT&P Labs

  45. 5. IPv6 Addressing Multicast Address Scope(4-bit):It indicates the scope of the multicasting: 0: Reserved 1: Confined to interfaces on the local node (node-local) 2: Confined to nodes on the local link (link-local) 5: Confined to the local site 8: Confined to the organization E: Global scope F: Reserved Group ID: It identifies the multicast group. SCUT DT&P Labs

  46. 5. IPv6 Addressing Multicast Address Certain special-purpose multicast addresses: FF01::1 All interface node-local (Defines all interface on the host itself); FF02::1 All nodes link-local (Defines all systems on the local network); FF01::2 All routers node-local (Defines all routers local to the host itself); FF02::2 All routers link-local (Defines all routers on the same link as the host); FF05::2 All routers site-local (Defines all routers on the same site as the host); SCUT DT&P Labs

  47. 5. IPv6 Addressing Multicast Address Certain special-purpose multicast addresses: FF02::B Mobile agents link-local; FF02::1:2 All DHLC agents link-local; FF05::1:3 All HDLC servers site-local; Note: The flags of all above special-purpose multicast address are 0000 (defined by the numbering authority); The function scope of the multicasting is determined by the scope field of the address; SCUT DT&P Labs

  48. 5. IPv6 Addressing Multicast Address Solicited node address: It is another special-purpose multicast address, which is used by ICMPv6 for neighbor discovery and to detect duplicate addresses. The format of a solicited node address FF02::1:FFxx:xxxx FF02::1:FF the prefix of the address; xx:xxxx the last 24 bits of a nodes unicast address SCUT DT&P Labs

  49. 5. IPv6 Addressing (3) Anycast Address Anycast address is a special type of unicast address that is assigned to interfaces on multiple hosts. Packets sent to such an address are delivered to the nearest interface with that address. The features of Anycast addresses: Same format as unicast addresses Must not be used as the source address May only be assigned to a router SCUT DT&P Labs

  50. 5. IPv6 Addressing Anycast Address Sub-router address: A special anycast address An sub-router address consists of the subnet prefix for a particular subnet followed by trailing zeros. The address may be used when a node needs to contact a router on a particular subnet. SCUT DT&P Labs

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