Cisco Cisco ASR 5000
SGSN Service Configuration Procedures
▀ Configuring IDFT for Connected Mode Handover (S4 Only, Optional)
▄ SGSN Administration Guide, StarOS Release 18
Configuring IDFT for Connected Mode Handover (S4 Only,
Optional)
The S4-SGSN supports the setup of indirect data forwarding tunnels (IDFT) between the eNodeB and the RNC via the
SGW during connected mode handovers. This allows the S4-SGSN to support connected mode handovers between the
UTRAN and E-UTRAN networks across the S3 interface.
SGW during connected mode handovers. This allows the S4-SGSN to support connected mode handovers between the
UTRAN and E-UTRAN networks across the S3 interface.
Once enabled, IDFT is employed under the following conditions:
If the SGSN is the old node participating in the connected mode handover:
The target node to which the connected mode handover is initiated should be an eNodeB (i.e., the
SGSN performs the handover to the MME.
The
enb-direct-data-forward
CLI setting is not configured in the target RNC configuration (in
RNC Configuration Mode).
If the SGSN is the new node participating in the connected mode handover:
The source node from which connected mode handover is initiated is an eNodeB (i.e., the MME is
performing a handover to the SGSN).
The enb-direct-data-forward CLI setting is not configured in the target RNC configuration (in RNC
Configuration Mode).
The source MME indicated that it does not support direct forwarding via a Forward Relocation Request.
Important:
If the target SGSN did not relocate to a new SGW, then IDFT does not apply. The target SGSN sets
up an indirect data forwarding tunnel with the SGW only if the SGW is relocated. If the SGW is not relocated, then the
source MME sets up the indirect data forwarding tunnel between the source eNodeB and the target RNC through the
SGW.
source MME sets up the indirect data forwarding tunnel between the source eNodeB and the target RNC through the
SGW.
Important:
By default, indirect data forwarding is enabled, and direct forwarding is disabled.
To configure IDFT for connected mode inter RAT handovers:
Step 1
Enter the context where the IuPS service is configured.
Step 2
Enter IuPS Service Configuration Mode and enter the configured IuPS service.
Step 3
Enter the RNC ID of the IuPS service for which you want to enable IDFT.
Step 4
Disable direct data forwarding for connected mode inter RAT handovers.
Example Configuration
config
context <context_name>
iups-service <iups_service_name>