IPv6


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IPv6 availability


Generally available with (new) versions of most operating systems.
BSD, Linux 2.2 Solaris 8
An option with Windows 2000/NT
Most routers can support IPV6


IPv6 Design Issues


Overcome IPv4 scaling problem
lack of address space.
Flexible transition mechanism.
New routing capabilities.
Quality of service.
Security.
Ability to add features in the future.


IPv6 Header Fields


VERS: 6 (IP version number)
Priority: will be used in congestion control
Flow Label: experimental - sender can label a sequence of packets as being in the same flow.
Payload Length: number of bytes in everything following the 40 byte header, or 0 for a Jumbogram.

Extension Headers

Routing Header - source routing
Fragmentation Header - supports fragmentation of IPv6 datagrams.
Authentication Header
Encapsulating Security Payload Header

IPv6 - IPv4 Programming

The kernel does the work, we can assume we are talking IPv6 to everyone!
In case we really want to know, there are some macros that determine the type of an IPv6 address.
We can find out if we are talking to an IPv4 client or server by checking whether the address is an IPv4 mapped address.