Дорожная карта для Cisco Cisco Packet Data Gateway (PDG)
Serving GPRS Support Node (SGSN) Overview
Features and Functionality - Basic ▀
Cisco ASR 5000 Series Product Overview ▄
OL-22938-01
Paging
CS-Paging is initiated by a peer node - such as the MSC - when there is data to be sent to an idle or unavailable UE. CS-
paging requires the Gs interface. This type of paging is intended to trigger a service request from the UE. If necessary,
the SGSN can use PS-Paging to notify the UE to switch channels. Once the UE reaches the connected state, the data is
forwarded to it.
paging requires the Gs interface. This type of paging is intended to trigger a service request from the UE. If necessary,
the SGSN can use PS-Paging to notify the UE to switch channels. Once the UE reaches the connected state, the data is
forwarded to it.
Paging frequency can be controlled by configuring a paging-timer.
Service Request
The Service Request procedure is used by the MN in the PMM Idle state to establish a secure connection to the SGSN
as well as request resource reservation for active contexts.
as well as request resource reservation for active contexts.
The SGSN allows configuration of the following restrictions:
Prohibition of services
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 on configurable 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 on configurable 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.