Table of Contents 1. Introduction 3.1 Before S1 Release |
1. Introduction
This document will describe procedures for releasing S1 connection when a UE becomes inactive, as in EMM Case 3 defined in our technical document, “Eleven EMM Cases in an EMM Scenario”[1]. While inactive, the UE - registered at the network, but not in use of any service – does not use any radio resources allocated by eNB. So, among the allocated resources, the network releases those associated with radio access, and deletes their related information (e.g. IDs, QoS parameters, etc.).
From a network’s perspective, S1 release means releasing the S1 signaling and RRC connections in control plane, and the downlink S1 bearer and DRB (Data Radio Bearer) in user plane, that are associated with a UE. However, from a UE’s perspective, it means losing its RRC connection and DRB in control and user planes, respectively. Once S1 connection is released, the ECM connection between UE and MME is lost, and all contexts associated with the UE are deleted at eNB. Then, the user transits from ECM-Connected to ECM-Idle state at the UE and MME, but remains in EMM-Registered state even after the transit.
This document explains the procedures for S1 release due to user inactivity in an LTE network.
Chapter 2 provides a description of how S1 release is performed, and
Chapter 3 summarizes what information elements are changed after the S1 release procedure.
In this document, at chapter I. Introduction, p.3 (of the PDF), in the second paragraph it is written:
“From a network’s perspective, S1 release means releasing the S1 signaling and RRC connections in user plane, and the downlink S1 bearer and DRB (Data Radio Bearer) in user plane,”
… I think that the correct should be:
"From a network’s perspective, S1 release means releasing the S1 signaling and RRC connections in CONTROL plane, and the downlink S1 bearer and DRB (Data Radio Bearer) in user plane"
BR
Vassilis
Very good presentation of the information
Very Good and in depth knowldege.
Thanks
Thank you Netmanias! Great Work !
I have a small query. In the shown diagrams "ECGI" value is been removed from PGW and PCRF as well (page 3). Just wanted to understand what message updated it, since there was no message towards PGW in S1 release call flow on page 2.