Handling the TAU and Location update Request/Response

Feature Summary and Revision History

Summary Data

Applicable Product(s) or Functional Area

MME

Applicable Platform(s)

  • ASR 5500

  • VPC-DI

  • VPC-SI

Feature Default

Enabled - Always-on

Related Changes in This Release

Not applicable

Related Documentation

MME Administration Guide

Revision History

Revision Details

Release

MME sends Location Update Request/Response.

21.12.2

First introduced.

Pre 21.3

Handling the TAU and Location Update Request/Response

This behaviour is only applicable when all the following conditions are met:

  • CIOT UE combined attached

  • With UE in PSM or EDRX mode, data being sent to the UE, MME rejects the DDN with EGTP_CAUSE_UNABLE_TO_PAGE_UE

  • Buffering starts in S-GW and with UE sending TAU with type as IMSI attach.

Previous Behavior: MME does not send modify bearer request, affecting buffering at S-GW.

New Behavior: UE triggers TAU, results in MME sending Location Update Request/Response. MME sends TAU Accept to UE (with S1 downlink-nas to eNB). With UE sending TAU Complete, MME sends TMSI Relocation Complete to MSC and Modify Bearer Request towards S-GW.