What are the IEs will be included in Notify request message when PGW id is changed at MME?

Question

In the deployed network,

Answer 1

As per my knowledge of LTE, Once a UE gets attached to LTE network, PGW doesn't change until the UE de-register from network. When UE requests to network to connect new APN and PGW selection is dynamic, in that case MME notifies to HSS about PGW id by using "Notify Request" message over S6a interface.

Notify Request message has "PDN GW Identity field" which tells to HSS about PGW Identity.

Comments

What about pgw plmn id,context id,APN these fields also related to PGW only na will you tel these IEs also included with pgw id field?

Answer 2

If the MME selects a PDN GW that is different from the PDN GW identity which was indicated by the HSS in the PDN subscription context, the MME shall send a Notify Request including the APN and PDN GW identity to the HSS for mobility with non-3GPP accesses. The message shall include information that identifies the PLMN in which the PDN GW is located.

source : http://www.rcrwireless.com/20140509/wireless/lte-attach-procedure-call-flow