Cisco Cisco ASR 5000
Serving GPRS Support Node (SGSN) Overview
Features and Functionality ▀
SGSN Administration Guide, StarOS Release 18 ▄
NRI-FQDN based DNS resolution for non-local RAIs (2G subscribers)
The SGSN now supports use of NRI-RAI based address resolution which includes both local lookup as well as DNS
Query for non-local RAIs when selection of the call control profile is based on the old-RAI and the PLMN Id of the
BSC where the subscriber originally attached. This feature was formerly supported only for 3G subscribers and is now
extended to 2G subscribers. The command enables the SGSN to perform address resolution for peer SGSN with an NRI
when an unknown PTMSI (Attach or RAU) comes from an SGSN outside the pool. The SGSN uses NRI-RAI based
address resolution for the non-local RAIs for 2G subscribers in place of RAI based address resolution.
Query for non-local RAIs when selection of the call control profile is based on the old-RAI and the PLMN Id of the
BSC where the subscriber originally attached. This feature was formerly supported only for 3G subscribers and is now
extended to 2G subscribers. The command enables the SGSN to perform address resolution for peer SGSN with an NRI
when an unknown PTMSI (Attach or RAU) comes from an SGSN outside the pool. The SGSN uses NRI-RAI based
address resolution for the non-local RAIs for 2G subscribers in place of RAI based address resolution.
This functionality is applicable in situations for either inter- or intra-PLMN when the SGSN has not chosen a local NRI
value (configured with SGSN Service commands) other than
value (configured with SGSN Service commands) other than
local-pool-rai
or
nb-rai
. This means the RAI
(outside pool but intra-PLMN) NRI length configured here will be applicable even for intra-PLMN with differently
configured NRI lengths (different from the local pool). This functionality is not applicable to call control profiles with
an associated MSIN range as ccprofile selection is not IMSI-based.
configured NRI lengths (different from the local pool). This functionality is not applicable to call control profiles with
an associated MSIN range as ccprofile selection is not IMSI-based.
NRI Handling Enhancement
The SGSN's DNS lookup for SGSN pooling is supported in the call control profile. Previously, the SGSN's complete Gn
DNS database had to be configured in the call control profile. If there was more than one SGSN in the local pool, then
there would be multiple instances for every SGSN in the pool.
DNS database had to be configured in the call control profile. If there was more than one SGSN in the local pool, then
there would be multiple instances for every SGSN in the pool.
By using just the NRI value, this enhancement facilitates lookup for a peer SGSN in the local pool.
NRPCA - 3G
The SGSN supports the Network Requested Primary PDP Context Activation (NRPCA) procedure for 3G attachments.
There are no interface changes to support this feature. Support is configured with existing CLI commands (network-
initiated-pdp-activation, location-area-list) in the call control profile configuration mode and timers (
initiated-pdp-activation, location-area-list) in the call control profile configuration mode and timers (
T3385-timeout
and
max-actv-retransmission
) are set in the SGSN service configuration mode.
NRSPCA Support for S4-SGSN
The SGSN supports Secondary PDP context activation by the network. 3GPP TS 23.060 specifies two procedures for
GGSN-initiated PDP Context Activation:
GGSN-initiated PDP Context Activation:
Network Requested PDP Context Activation (NRPCA) - the SGSN already supports this but only for 3G access,
and
Network Requested Secondary PDP Context Activation (NRSPCA) Procedure.
NRSPCA allows the network to initiate Secondary PDP context activation if the network determines that the service
requested by the user requires activation of an additional secondary PDP context. Network requested bearer control
makes use of the NRSPCA procedure.
requested by the user requires activation of an additional secondary PDP context. Network requested bearer control
makes use of the NRSPCA procedure.
Network requested bearer control functionality is mandatory in EPC networks, requiring use of NRSPCA. The P-GW
supports only the NRSPCA procedure. With this release, now the S4-SGSN supports network requested bearer control.
supports only the NRSPCA procedure. With this release, now the S4-SGSN supports network requested bearer control.
For a complete description of this feature and its configuration requirements, refer to the Network Requested Secondary
PDP Context Activation chapter in the Serving GPRS Support Node Administration Guide
PDP Context Activation chapter in the Serving GPRS Support Node Administration Guide