Created as a result of the lacking amount of IP address spaces. Even with private networks and CIDR we still don’t have enough IPv4 addresses

IPv6 has a few improvements over v4

• More address spaces. 2^128 to be exact
• Hierarchical address spaces
• Auto-configurations
• Built-in Quality of Server support
• Built in support for security

IPv6 Addresses

• A v6 address is 128 bits or 16 bytes long. 4 times as large as a v4 address
• Written in colon decimal notation
• Written in hexadecimal instead of decimal

0000:0000:0000:0000:FFFF:FFFF:FFFF:FFFF

Zero Compression

• Rule 1: When only 0 is in a quad then it is removed from the ipv6 address notation
• Rule 2: When continuous zeros are available in IPv6 address notation, then all zeros replaced by ::
• Rule 3: When zeros are present in discontinuous places then at only one junction, 0s are replaced with ::

FDEC:0000:0000:0000:0000:BFF:0000:FFFF - origional address
FDEC:0:0:0:0:BBFF:0:FFFF -> FDEC::BBFF::FFFF - Broken down then compressed

Types of Addresses

• Unicast - defines single interface or device
• Anycast - defines a group of recipients that share a single address. Message is sent to only one member of an address, the most reachable
• Multicast - defines a group of recipients that share a single address. Message is sent to all members of address
• Broadcast addresses are not used in IPv6

Address Space Allocation

• IPv6 is divided into several blocks of 1/8
• Divided logically by address prefix
• If an IPv6 address has a prefix of 00000000 and the remaining bits are 0 that means the device has no address
• If connections between v4 and v6 as well as connections over said networks need to occur, IPv6 sets all bits to 0 and the end bits become a small enough address to resemble an IPv4 address

Link Local Addressing

• When communicating on a local network IPv6 does some interesting logic.
• It uses the devices mac address to create a unique 64 bit string identifier to be used as a link local address.
• It rearranges the address by flipping a bit and moving bytes around.

IPv6 Header

• Fields - Its a lot cleaner with less fields
  • Version
  • Traffic Class
    • 8bits
    • Used for routing priority
  • Flow Label
    • 20 bits
    • id’s a group of packets, like a session or media stream
  • Payload Length
    • 16 bits
    • Number of bytes carried. Does not include header bytes
  • Next Header
    • Shows either protocol or an extension header. It shows what is supposed to be coming behind it
  • Hop Limit
  • Source Address
  • Destination Address
• Next Header Types
  • 1. basic ipv6 header -
  • 2. hop by hop operations 0
  • 3. destination options 60
  • 4. routing header 43
  • 5. fragment header 44
  • 6. authentication header 51
  • 7. encapsulation security payload header 50
  • 8. destination options 60
  • 9. mobility header 135
  • no next header
  • upper layer TCP
  • upper layer UDP
  • upper layer ICMPv6

Security

• IPSec is built in
• Different header security
  • AH - Authentication Header (header only)
  • ESP - Encapsulated Security Payload (header and payload)
• Modes
  • transport mode
  • tunnel mode