Cisco Cisco ASR 5000
Serving GPRS Support Node (SGSN) Overview
▀ SGSN Core Functionality
▄ SGSN Administration Guide, StarOS Release 18
Enforce identity check
PLMN restriction
Roaming restrictions
Authentication
The SGSN authenticates the subscriber via the authentication procedure. This procedure is invoked on attaches, PDP
activations, inter-SGSN routing Area Updates (RAUs), and optionally by configuration for periodic RAUs. The
procedure requires the SGSN to retrieve authentication quintets/triplets from the HLR (AuC) and issuing an
authentication and ciphering request to the MN. The SGSN implements an in-memory data-VLR functionality to pre-
fetch and store authentication vectors from the HLR. This decreases latency of the control procedures.
activations, inter-SGSN routing Area Updates (RAUs), and optionally by configuration for periodic RAUs. The
procedure requires the SGSN to retrieve authentication quintets/triplets from the HLR (AuC) and issuing an
authentication and ciphering request to the MN. The SGSN implements an in-memory data-VLR functionality to pre-
fetch and store authentication vectors from the HLR. This decreases latency of the control procedures.
Additional configuration at the SGSN allows for the following:
Enforcing ciphering
Retrieval of the IMEI-SV
P-TMSI Reallocation
The SGSN supports standard Packet-Temporary Mobile Identity (P-TMSI) Reallocation procedures to provide identity
confidentiality for the subscriber.
confidentiality for the subscriber.
The SGSN can be configured to allow or prohibit P-TMSI reallocation on the following events:
Routing Area Updates
Attaches
Detaches
Service Requests
The SGSN reallocates P-TMSI only when necessary.
P-TMSI Signature Reallocation
The SGSN supports operator definition of frequency and interval for Packet Temporary Mobile Subscriber Identity (P-
TMSI) signature reallocation for all types of routing area update (RAU) events.
TMSI) signature reallocation for all types of routing area update (RAU) events.
Identity Request
This procedure is used to retrieve IMSI and IMEI-SV from the MN. The SGSN executes this procedure only when the
MN does not provide the IMSI and the MM context for the subscriber is not present in the SGSN’s data-VLR.
MN does not provide the IMSI and the MM context for the subscriber is not present in the SGSN’s data-VLR.
Location Management
The SGSN’s 3GPP compliance for location management ensures efficient call handling for mobile users.
The SGSN supports routing area updates (RAU) for location management. The SGSN implements standards based
support for:
support for:
Periodic RAUs