Cisco Cisco Packet Data Gateway (PDG)
Evolved Packet Data Gateway Overview
How the ePDG Works ▀
ePDG Administration Guide, StarOS Release 18 ▄
73
Step Description
2.
On receiving the IKEv2 INFORMATIONAL Request with Delete from the UE, the ePDG begins the disconnection of the
WLAN UE session. It begins the tear down the session by sending Delete quest (Linked Bearer ID) to P-GW to disconnect
the session.
WLAN UE session. It begins the tear down the session by sending Delete quest (Linked Bearer ID) to P-GW to disconnect
the session.
3.
P-GW sends back the Delete Session Response message acknowledging the session deletion.
4.
ePDG disconnects the SWm session with sending a Session-Terminate-Request (STR) to the 3GPP AAA.
5.
3GPP AAA clears the SWn sessions and responds back to the ePDG with a Session-Terminate-Ack (STA).
6.
The ePDG responds back to the UE's IKEv2 INORMATION request with a IKEv2 INFORMATIONAL RSP.
ePDG-initiated Session Disconnection
The figure below shows the message flow during an ePDG-initiated session disconnection. The table that follows the
figure describes each step in the message flow.
figure describes each step in the message flow.
Figure 19. ePDG-initiated Session Disconnection
Table 14. ePDG-initiated Session Disconnection
Step
Description
1.
An Admin/AAA trigger causes the ePDG to start disconnecting the WLAN UE session by sending an IKEv2
INFORMATIONAL (DELETE) Request message. The encrypted payload has a single DELETE payload that contains the
SPI of the IKEv2 SA corresponding to the WLAN UE session being disconnected.
INFORMATIONAL (DELETE) Request message. The encrypted payload has a single DELETE payload that contains the
SPI of the IKEv2 SA corresponding to the WLAN UE session being disconnected.