Cisco Cisco ASR 5000
Direct Tunnelling for the S4-SGSN
▀ How It Works
▄ SGSN Administration Guide, StarOS Release 18
Figure 42. PGW Init Modification when UE in Idle State
Limitations
During an intra RAU, intra SRNS or Service Request triggered by RAB establishment, if a few RABs fail the Modify
Bearer Request the SGSN will mark those RABs as bearers to be removed. Under current specifications, it is not
possible to send a Modify Bearer Request with a few bearers having S12U U-FTEIDs and a few bearers not having U-
FTEIDs.
Bearer Request the SGSN will mark those RABs as bearers to be removed. Under current specifications, it is not
possible to send a Modify Bearer Request with a few bearers having S12U U-FTEIDs and a few bearers not having U-
FTEIDs.
There is an ongoing CR at 3GPP to allow such Modify Bearer Requests and the S-GW should send DDN when it gets
downlink data for the bearers that did not have U-FTEIDs. If this CR is approved, the SGSN will support (in a future
release) sending a partial set of bearers with S12U FTEID and some bearers without any U-FTEID.
downlink data for the bearers that did not have U-FTEIDs. If this CR is approved, the SGSN will support (in a future
release) sending a partial set of bearers with S12U FTEID and some bearers without any U-FTEID.
Standards Compliance
The Direct Tunnel complies with the following standards:
3GPP TS 23.060 version 10 sec 9.2.2 – General Packet Radio Service (GPRS); Service description
3GPP TS 29.274 v10.5.0 – 3GPP Evolved Packet System (EPS); Evolved General Packet Radio Service (GPRS)
Tunnelling Protocol for Control plane (GTPv2-C)