Mobile Packet Core

For the UE to be able to send and receive data to and from the PDN, it must have an active PDP .

In turn, 'PDP context' should exist on the UE, the SGSN, and the GGSN.

This PDP context can be in one of two states. Those two states are the Session Management states 'SM states'.

SM states

The 'SM sates' are 'INACTIVE' and 'ACTIVE'.

INACTIVE state

In this state, the UE can’t send or receive data to and from the PDN.

ACTIVE state

In this state, the UE can send and receive data to and from the PDN.

Transition between ACTIVE and INACTIVE states

Moving from ACTIVE to INACTIVE,

The SM state, moves to INACTIVE state when,

• 'PDP context deactivation' procedure is initiated.

• The MM state of the UE moves to IDLE in 2G, or PMM-DETACHED in 3G.

Moving from INACTIVE to ACTIVE,

• The SM state moves from INACTIVE to ACTIVE state, when a 'PDP context activation' procedure is done.

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