SIPP Overview


SIPP is a new version of IP which is designed to be an evolutionary step from IPv4. It is a natural increment to IPv4. It can be installed as a normal software upgrade in internet devices and is interoperable with the current IPv4. Its deployment strategy is designed to not have any flag days or other dependencies. SIPP is designed to run well on high performance networks (e.g. ATM) and at the same time is still efficient for low bandwidth networks (e.g. wireless). In addition, it provides a platform for new internet functionality that will be required in the near future.

SIPP is designed to be the successor to IPv4 and is assigned IP version number 6. It was not a design goal to take a radical step away from IPv4. Functions which work in IPv4 were kept in SIPP. Functions which didn't work were removed. The changes from IPv4 to SIPP fall primarily into the following categories:

Expanded Routing and Addressing Capabilities

SIPP increases the IP address size from 32 bits to 64 bits, to support more levels of addressing hierarchy and a much greater number of addressable nodes. SIPP addressing can be further extended, in units of 64 bits, by a facility equivalent to IPv4's Loose Source and Record Route option, in combination with a new address type called "cluster addresses" which identify topological regions rather than individual nodes. The scaleability of multicast routing is improved by adding a "scope" field to multicast addresses.

Header Format Simplification

Some IPv4 header fields have been dropped or made optional, to reduce the common-case processing cost of packet handling and to keep the bandwidth cost of the SIPP header almost as low as that of IPv4, despite the increased size of the addresses. The basic SIPP header is only four bytes longer than IPv4.

Improved Support for Options

Changes in the way IP header options are encoded allows for more efficient forwarding, less stringent limits on the length of options, and greater flexibility for introducing new options in the future.

Quality-of-Service Capabilities

A new capability is added to enable the labeling of packets belonging to particular traffic "flows" for which the sender requests special handling, such as non-default quality of service or "real-time" service.

Authentication and Privacy Capabilities

SIPP includes the definition of extensions which provide support for authentication, data integrity, and confidentiality. This is included as a basic element of SIPP.

For more information on SIPP see the SIPP Protocol Specification and the SIPP Routing and Addressing Specification .