IP Address Auto Allocation in 3GPP


  3GPP address autoconfiguration has the following steps:


     1. The Activate PDP Context message is sent to the SGSN (PDP
        Type=IPv6, PDP Address = 0, etc.).

     2. The SGSN sends a Create PDP Context message to the GGSN with
        the above parameters.

     3. GGSN chooses an interface identifier for the PDP Context and
        creates the link-local address.  It answers the SGSN with a
        Create PDP Context response (PDP Address = link-local address).

     4. The SGSN sends an Activate PDP Context accept message to the UE
        (PDP Address = link-local address).

     5. The UE keeps the link-local address, and extracts the interface
        identifier for later use.  The UE may send a Router
        Solicitation message to the GGSN (first hop router).

     6. After the PDP Context Activation, the GGSN sends a Router
        Advertisement to the UE.

     7. The UE should be configured not to send a Neighbor Solicitation
        message.  However, if one is sent, the GGSN will silently
        discard it.

     8. The GGSN updates the SGSN with the whole IPv6 address.