IPv6-Addressing

IPv6 addressing

IPv4 and IPv6 coexsitence

• Methods that help administror to transmit from IPv4 to IPv6.
  1. Dual Stack: IPv4 and IPv6 coexist on the same network
  2. Tunneling: Transport IPv6 packet over IPv4 network by encapsulating the IPv6 packet into IPv4 packet.
  3. Translation: Like the NAT for IPv4, NAT64 translate the IPv4 packet

Format

• 128 bits
• represented by 32 hexadecimal digits which seperated by colons every four hexadecimal digits
• the block of four hexadecimal digits called hextet

Rules that reduce the digits

1. omit leading zeros in any hextec
2. double colon
   • double colon can replace any sigle, contiguous string of one or more 16-bit hextet consisting of all zeros.
   • double colon can be used only once with an adress.
   • if the address has more than one contiguous string of all zero hextet, the best prectice is to use the double colon on the longest string.
   • if length of the strings are equal, the first one shoule use the double colon

IPv6 address type

1. Unicast: Similar as IPv4

   • Global Unicast Address, gloablly unique internet routable address, it’s similar as the IPv4 public address and can be assigned statically and dynamically.
     • Currently, only GUAs with the first 3 bits are assigned.
     • 2000::/3
     • Composition
       • /48 Global routing prefix
       • /16 Subnet ID
       • /64 Interface ID
         All 0s address is reserved as subnet-router anycast address and it should be assigned only to routers

   • Link-local Address, it’s required for every IPv6 device. It’s used to communicate with the devices on the same local network, so the router will not forward packets with a link-local address.

     • fe80::/10
     • if the link-local address is not created manually, the device will create it automatically.
       • Generate the ramdon values
       • EUI (Extended Unique Identifier) method
         • Fisrt, split the MAC address into 2 pieces
         • Intsert FFFE in the middle of MAC address
         • Flip/Invert the 7th bit
   • Loop back address: ::1/128
   • Unique local address,it’s used for communicate within a orgnization or site, it’s sililar with the IPv4 private address.
     • fc00::/7

2. Multicast: Same as IPv4 : ff00:/8

   1. Well-Known Multicast Addresses
      • The addresses are assigned which are reserved multipul addresses for predefined gourp of devices. THe assigned adress is used to reach a group of device that running common protocol or service.
      • 2 common assigned multicast groups
        • ff02::1 All-nodes multicast gourp. Same as broadcast in IPv4
        • ff02::2 All-routers multicast group.
   2. Solicited-node Multicast Addresses
3. Anycast
   • Any unicast address can be assigned to multiple devices. A packet sent to an anycast address is routed to the nearest device having that address

IPv6 GUA (Global Unique Address) Assignment

• Configure the GUA mannually
  • GUA and LLA can both be specified as default gateway address. But LLA is recommended.