Cisco Cisco ASR 5000
Serving GPRS Support Node (SGSN) Overview
Features and Functionality ▀
SGSN Administration Guide, StarOS Release 18 ▄
APN-based congestion control for Mobility Management
APN-based congestion control for Session Management
Extended T3312 timer support
MM (Mobility Management) T3346 - MM Back-off Timer and SM (Session Management) T3396 - SM Back-
off Timer
For more information about the congestion control functionality and configuration, refer to the MTC Congestion
Control section in this Guide.
Control section in this Guide.
Different NRIs for Pooled and Non-pooled RNCs/BSCs
The SGSN adds support for configuring different NRIs for pooled and non-pooled areas in order to load-balance
subscribers coming from non-pooled RNCs to pooled RNCs.
subscribers coming from non-pooled RNCs to pooled RNCs.
Consider a scenario when two SGSNs support pooling and a RNC/BSC controlled by a SGSN is in pool but not the
other, and both RNCs/BSCs are given same NRI(s), this leads to imbalance in subscriber distribution between the
SGSNs. With this enhancement if an NRI is configured for both pooled and non-pooled, then the SGSN reuses the same
NRI when moving from pooled to non-pooled areas and vice versa.
other, and both RNCs/BSCs are given same NRI(s), this leads to imbalance in subscriber distribution between the
SGSNs. With this enhancement if an NRI is configured for both pooled and non-pooled, then the SGSN reuses the same
NRI when moving from pooled to non-pooled areas and vice versa.
A new keyword
non-pooled-nri-value
is introduced in the NRI configuration for GPRS and SGSN services to
configure set of NRI which should be used for non-pooled RNCs/BSCs. The NRIs configured under the existing
keyword
keyword
nri-value
will be used for pooled RNCs/BSCs. If the new keyword
non-pooled-nri-value
is not
configured, then NRIs configured under the keyword
nri-value
will be used for both pooled and non-pooled
RNCs/BSCs.
If the new keyword
non-pooled-nri-value
is configured without pooling enabled at SGSN(null-nri-value is not
configured), then SGSN will use NRIs under
non-pooled-nri-value
irrespective of BSC/RNCs being pooled or
non-pooled, till pooling is enabled at SGSN. After pooling is enabled, NRIs under keyword
nri-value
will be for
pooled RNC/BSCs and
non-pooled-nri-value
will be for non-pooled RNC/BSCs. This is applicable for both SGSN
and GPRS service.
Direct Tunnel
In accordance with standards, one tunnel functionality enables the SGSN to establish a direct tunnel at the user plane
level - a GTP-U tunnel, directly between the RAN and the GGSN. Feature details and configuration procedures are
provided in the Direct Tunnel feature section in this guide.
level - a GTP-U tunnel, directly between the RAN and the GGSN. Feature details and configuration procedures are
provided in the Direct Tunnel feature section in this guide.
Direct Tunnel Support on the S4-SGSN
Important:
With this release, this feature is qualified for lab and field trials only.
Direct tunnelling of user plane data between the RNC and the S-GW can be employed to scale UMTS system
architecture to support higher traffic rates. The direct tunnel (DT) approach optimizes core architecture without impact
to UEs and can be deployed independently of the LTE/SAE architecture.
architecture to support higher traffic rates. The direct tunnel (DT) approach optimizes core architecture without impact
to UEs and can be deployed independently of the LTE/SAE architecture.
Now, DT support is added to the S4-SGSN to enable the establishment of a direct tunnel over the S12 interface between
an RNC and an S-GW in a PS domain under a range of scenarios, such as (but not limited to):
an RNC and an S-GW in a PS domain under a range of scenarios, such as (but not limited to):
Primary PDP activation