5.13 Support for Machine Type Communications (MTC)

23.4023GPPArchitecture enhancements for non-3GPP accessesRelease 18TS

5.13.1 General

Support for Machine Type Communications (MTC) is described in TS 23.401 [4]. The common procedures and functionalities are only captured in TS 23.401 [4].

5.13.2 PDN GW control of overload

The PDN GW may provide mechanisms for avoiding and handling overload situations. These include the rejection of PDN connection requests from UEs.

When PMIP is used for S5/S8 interface, PDN GW may reject the PDN connection request (i.e. Proxy Binding Update) with indication that the APN is congested. In addition the PDN GW may indicate a "PDN-GW back-off time" for a specific APN to the MME in the reject message.

Other PDN GW functionalities and the behaviour of Serving GW/MME/SGSN upon receiving the reject messages are described in TS 23.401 [4].

5.13.3 Usage of low access priority indicator

For PDN connection establishment requests, the SGSN/MME includes the low access priority indicator in the request message to the Serving GW/PDN Gateway. The Serving GW shall forward the indicator to PDN GW in Proxy Binding Update message.

Other functions related to indicators are described in TS 23.401 [4].