IPV6

• Features
  • 128 bit address.
    • 6x10²³ addresses for every m² on earth
    • Assigned to interfaces, not to nodes.
    • Interfaces may have multiple addresses assigned to them.
    • These addresses can be aggregated to provide faster routing and smaller routing tables.
  • A 40 byte header.
    • Options from IPV4 have been moved to follow on headers.
    • 
    • Version number, like IPV4
    • DS/ECN fields as IPV4
    • Flow labels
      • Allows the source to request special handling.
      • Such as QOS or Real time service
      • This field is randomly generated (like ports)
      • Routers keep a table of these fields and negotiated parameters.
      • The router performs the services pre-requested on each packet where this field matches. (And other requirements)
    • Payload Length: extension headers + data
    • Next header: IPV6 extension or UDP or TCP or other high level protocol.
    • Hop limit: TTL
  • Extended headers
    • 
    • HOP-BY-HOP header
      • information that every router along the path must look at.
    • Routing Header
      • Information on the route the packet must follow.
    • Fragment Header
      • Fragmentation is done on source nodes.
      • Must do a network discovery to find MTU
      • This field holds the fragment info from IPV4
    • Authentication header
    • Encapsulation Security Payload header
    • Destination Options header.