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IPv6 Addressing

IPv6 Addressing. Agenda. OSI & TCP/IP Model IPv4 Addressing IPv6 Addressing. APPLICATION. APPLICATION. PRESENTATION. SESSION. TCP/IP Model. OSI Model. TRANSPORT. TRANSPORT. NETWORK. NETWORK. DATA LINK. DATA LINK. PHYSICAL. PHYSICAL. TCP/IP and OSI. OSI is made of seven layers.

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IPv6 Addressing

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  1. IPv6 Addressing

  2. Agenda • OSI & TCP/IP Model • IPv4 Addressing • IPv6 Addressing

  3. APPLICATION APPLICATION PRESENTATION SESSION TCP/IP Model OSI Model TRANSPORT TRANSPORT NETWORK NETWORK DATA LINK DATA LINK PHYSICAL PHYSICAL TCP/IP and OSI • OSI is made of seven layers. • TCP/IP protocol is made of five layers.

  4. Application TCP Header Data TPT Layer TCP Segment UDP Header Data UDP Message NW Layer IP Header TCP-UDP Data IP Datagram Data Link Frame Head IP Header TCP-UDP Data Trailer Frame Data Encapsulation Data

  5. FTPSMTPTELNETHTTP TFTPNFSSNMPDNS A T TCP UDP N IP D Protocols defined by the underlying networks P TCP/IPv4 Protocol Suite.. ICMP IGMP ARP RARP

  6. Octet +0 Octet +1 Octet +2 Octet +3 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7 VER HLEN TOS TOTAL LENGTH IDENTIFICATION DF MF FRAGMENT OFFSET TIME TO LIVE PROTOCOL HEADER CHECKSUM SOURCE ADDRESS OF HOST DESTINATION ADDRESS OF HOST OPTIONS PADDING IP Header..

  7. Here is my MAC address Give me MAC address of 129.1.1.4 129.1.1.1 129.1.1.4 ARP Response Accepted That’s Me 08-00-10-99-AC-54 129.1.1.2 129.1.1.3 08-00-39-00-2F-AB 08-00-39-00-2F-C3 08-00-5A-21-A7-22 ARP Operation Request Ignored Request Ignored

  8. Give me my IP address RARP Response Diskless work station RARP Server 08-00-39-00-2F-AB 223.1.2.3 223.1.2.1 08-00-39-00-2F-C3 223.1.2.2 08-00-10-99-AC-54 08-00-5A-21-A7-22 RARP Operation

  9. IPv4 Header Version(4) HeaderLength (4) Priority & Type of Service (8) Total Length (16) Flags(3) Fragment offset (13) Identification (16) 20Bytes Time to live (8) Protocol (8) Header checksum (16) Source IP Address (32) Destination IP Address (32) Removed Changed

  10. IPv6 Header Version(4) Traffic Class(8) Flow Label(20) Next Header(8) Hop Limit(8) Payload Length(16) 40 Bytes Source IP Address (128) Destination IP Address (128) New

  11. Extension Header • New way of doing options • • Added after the basic IPv6 header • • Daisy chained IPv6 Header Next Header = TCP TCP Header + Data IPv6 Header Next Header = Routing Routing Header Next Header = TCP TCP Header + Data IPv6 Header Next Header = Routing Routing Header Next Header = ESP ESP Header Next Header = TCP TCP Header + Data

  12. Summary • Comparison of IPv4 and IPv6 headers shows a longer header, but less number of fields • Header processing is simpler • Options are handled by extension headers • Routing header for source routing changes the destination address in the IP header

  13. 32 Bits Network Host IPv4 Addressing 8 Bits 8 Bits 8 Bits 8 Bits 172 . 16 . 122 . 204 ALTTC/DX/SC/IPADDRESSING

  14. IPv4 Address Scheme • Two types of addressing schemes for IPv4 • Classful • Classless • Classful • Original style of addressing based on first few bits of the address. • Generally used in customer sites. • Classless • A new type of addressing that disregards the class bit of an address and applies a variable prefix (mask) to determine the network number. ALTTC/DX/SC/IPADDRESSING

  15. Class-A: N H H H Class-B: N N H H Class-C: N N N Class-D: For Multicast Class-E: For Research IPv4 Address classes H • N=Network number assigned by IR. • H=Host number assigned by network administrator. ALTTC/DX/SC/IPADDRESSING

  16. A 0 7 bits Network Address 24 bits Host Address B 10 14 bits Network Address 16 bits Host Address C 110 21 bits Network Address 8 bits Host Address D 1110 Multicast address (224.0.0.0-239.255.255.255) E 1111 Reserved for future use Identifying a class of address Address Identifier Network Address Host Address ALTTC/DX/SC/IPADDRESSING

  17. 8 Bits 8 Bits 8 Bits 8 Bits Class-A: 01 1 1 1 1 1 1 0 0 0 0 0 0 0 0 0-127 Class-B: 128-191 10 1 1 1 1 1 1 10 0 0 0 0 0 0 Class-C: 110 1 1 1 1 1 110 0 0 0 0 0 192-223 Class-D: 1110 0 0 0 0 1110 1 1 1 1 224-239 Class-E: 11111 1 1 1 11110 0 0 0 240-255 IP Address Bit Patterns ALTTC/DX/SC/IPADDRESSING

  18. Networks Vs Hosts • In Classless environment we can have232=4294967296 Hosts • ClassNetworksHosts/Network • A 126 16777214 • B 16384 65354 • C 2097152 254 ALTTC/DX/SC/IPADDRESSING

  19. Private Address Space • IANA has reserved the following three blocks of the IP address space for private internets (RFC 1918): • 10.0.0.0 - 10.255.255.255 (10.0.0.0/8 prefix) • 24-bit block • Complete class-A network number • 172.16.0.0 - 172.31.255.255 (172.16.0.0/12 prefix) • 172.0001/0000.0.0-172.0001/1111.255.255 • 20-bit block • Set of 16 contiguous class-B network numbers • 192.168.0.0 - 192.168.255.255 (192.168.0.0/16 prefix) • 16-bit block • Set of 256 contiguous class-C network numbers ALTTC/DX/SC/IPADDRESSING

  20. IPv6 Addressing • IPv6 addresses • Format • Unicast • Multicast • Anycast • Required Node Addresses • Address Selection • Addressing Architecture

  21. Addresses • IPv4 = 32 bits • IPv6 = 128 bits – This is not 4 times the number of addresses – This is 4 times the number of bits – ~3,4 * 1038 possible addressable nodes – 1030 addresses per person on the planet – Well, as with any numbering scheme, we will be using only a portion of the full address space

  22. Address Format • x:x:x:x:x:x:x:x – Where x is a 16 bits hexadecimal field • 2001:0000:1234:0000:0000:C1C0:ABCD:0876 • Case insensitive • 2001:0000:1234:0000:0000:c1c0:abcd:0876 • Leading zeros in a field are optional: • 2001:0:1234:0:0:C1C0:ABCD:876

  23. Address format • Successive fields of 0 are represented as ::, but only once in an address: – 2001:0:1234::C1C0:ABCD:876 – Not valid: 2001::1234::C1C0:ABCD:876 • Other examples: – FF02:0:0:0:0:0:0:1 => FF02::1 – 0:0:0:0:0:0:0:1 => ::1 – 0:0:0:0:0:0:0:0 => ::

  24. Addresses in URL • In a URL, it is enclosed in brackets – http://[2001:1:4F3A::206:AE14]:8080/index.html – URL parsers have to be modified – Cumbersome for users • Mostly for diagnostic purposes • Should use Fully Qualified Domain Names (FQDN)

  25. Address Types • Unicast – Unspecified – Loopback – Scoped addresses: • Link-local • Site-local (Deprecated now) • Unique-Local – Aggregatable Global: • Multicast – Broadcast: none in IPv6 • Anycast

  26. Unspecified • Used as a placeholder when no address available – Initial DHCP request – Duplicate Address Detection (DAD) • Like 0.0.0.0 in IPv4 0:0:0:0:0:0:0:0 or ::

  27. Loopback • Identifies self • Localhost • Like 127.0.0.1 in IPv4 • 0:0:0:0:0:0:0:1 or ::1 • To find if your IPv6 stack works: – Ping6 ::1

  28. Link-Local • Scoped address (new in IPv6) • Scope = local link (i.e. VLAN, subnet) – Can only be used between nodes of the same link – Cannot be routed • Automatically configured on each interface – Uses the interface identifier (based on MAC address) • Format: – FE80:0:0:0:<interface identifier> • Gives every node an IPv6 address to start communications

  29. Site-Local( now ULA) • Scoped address • Scope = site (a network of links) – Can only be used between nodes of the same site – Cannot be routed outside the site (i.e. the Internet) – Very similar to IPv4 private addresses • Not configured by default

  30. Unique local address • ULA is an IPv6 address in the block fc00::/7 defined in RFC 4193. • To be used for systems that are not connected to the Internet. • Divided into two /8 address groups • assigned and random • valid /48 prefixes are derived

  31. Aggregatable Global • Generic use. Globally reachable. • Allocated by IANA – To Regional Registries – Then to Tier-1 Providers • Called Top-level Aggregator (TLA) – Then to Intermediate Providers • Called Next-level Aggregator (NLA) – Then to sites – Then to subnets

  32. Aggregatable Global • Structure: TLA RES NLAs SLA Interface ID 48 bits 16 bits 64 bits • 128 bits as the total • • 48 bits prefix to the site • • 16 bits for the subnets in the site • • 64 bits for host part

  33. Aggregatable Global • Consists of the following (left to right): – 3 bits: 001 (10% of the total address space reserved) – 13 bits for the TLA • 213 TLAs ~ 8K TLAs – 8 bits reserved – 24 bits for the NLAs • 224 NLAs per TLA ~ 16M NLAs per TLA – 16 bits for the site subnets • 216 subnets per site = 65536 subnets – 64 bits for the interface identifier – Total = 128 bits.

  34. Multicast • Multicast = one-to-many • No broadcast in IPv6. Multicast is used instead, mostly on local links • Scoped addresses: – Node, link, site, organisation, global – No TTL as in IPv4 • Format: – FF<flags><scope>::<multicast group>

  35. Multicast assigned Addresses • Some reserved multicast addresses:

  36. Anycast • One-to-nearest: great for discovery functions • Anycast addresses are indistinguishable from unicast addresses – Allocated from the unicast addresses space – Some anycast addresses are reserved for specific uses • Few uses: – Router-subnet – MobileIPv6 home-agent discovery – discussions for DNS discovery

  37. Required Node Addresses • Any IPv6 node should recognize the following addresses as identifying itself: – Link-local address for each interface – Assigned (manually or automatically) unicast/anycast addresses – Loopback address – All-nodes multicast address – Solicited-node multicast address for each of its assigned unicast and anycast address – Multicast address of all other groups to which the host belongs

  38. Thanks

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