Moxa ANT-WSB-ANM-05 Manuel D’Utilisation
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2009 Industrial Wireless Guidebook
Cellular Networks
3
Packet Switching Data Solution: GPRS
General Packet Radio Service (GPRS) provides Packet Switching service to GSM systems. A GSM system
is traditionally a Circuit Switching network that provides optimized voice transmission service. For instance,
a call between Party A and Party B will exclude other parties. Even if Party A and Party B temporarily fall
into silence during their conversation, the call (network resource) won’t be released until either end hangs
up. As a result, the network resource is wasted when a data call is utilized in a GSM network. That is
because data transmission doesn’t necessarily need real-time transmission, which is primarily required for
voice or video communications. A few seconds delay won’t change the correctness and consequence in
data transmission. Take email uploads and downloads for example. The network resource is occupied only
when data is transmitted through the packet switching system. As a result, other users can freely send their
data when the system is “inactive.” Accordingly, consumers benefit from the low cost and real-time data
transmission of GSM networks.
is traditionally a Circuit Switching network that provides optimized voice transmission service. For instance,
a call between Party A and Party B will exclude other parties. Even if Party A and Party B temporarily fall
into silence during their conversation, the call (network resource) won’t be released until either end hangs
up. As a result, the network resource is wasted when a data call is utilized in a GSM network. That is
because data transmission doesn’t necessarily need real-time transmission, which is primarily required for
voice or video communications. A few seconds delay won’t change the correctness and consequence in
data transmission. Take email uploads and downloads for example. The network resource is occupied only
when data is transmitted through the packet switching system. As a result, other users can freely send their
data when the system is “inactive.” Accordingly, consumers benefit from the low cost and real-time data
transmission of GSM networks.
General packet radio service (GPRS) is a packet-oriented mobile data service available to 2G and 3G GSM
users.
users.
A GSN (GPRS Support Node) is a network node that supports the use of GPRS in the GSM core network.
All GSNs should have a Gn interface and support the GPRS tunneling protocol. There are two key variants
of the GSN, namely Gateway (GGSN) and Serving GPRS Support Node (SGSN).
• Serving GPRS Support Node (SGSN)
All GSNs should have a Gn interface and support the GPRS tunneling protocol. There are two key variants
of the GSN, namely Gateway (GGSN) and Serving GPRS Support Node (SGSN).
• Serving GPRS Support Node (SGSN)
A Serving GPRS Support Node (SGSN) is responsible for the delivery of data packets from and to the
mobile stations within its geographical service area. Its tasks include packet routing and transfer, mobility
management (attach/detach and location management), logical link management, and authentication and
charging functions. The location register of the SGSN stores location information (e.g., current cell, current
VLR) and user profiles (e.g., IMSI (ID code of the SIM card) addresses used in the packet data network) of
all GPRS users registered with a particular SGSN.
mobile stations within its geographical service area. Its tasks include packet routing and transfer, mobility
management (attach/detach and location management), logical link management, and authentication and
charging functions. The location register of the SGSN stores location information (e.g., current cell, current
VLR) and user profiles (e.g., IMSI (ID code of the SIM card) addresses used in the packet data network) of
all GPRS users registered with a particular SGSN.
• Gateway GPRS Support Node (GGSN)
The Gateway GPRS Support Node (GGSN) is a main component of GPRS networks. The GGSN is
responsible for connecting the GPRS network to external packet switched networks such as the Internet
and X.25 networks.
The GGSN stores the current SGSN address of the user and his or her profile in its location register. The
GGSN is responsible for IP address assignment and is the default router for the connected user equipment
(UE). The GGSN also performs authentication and charging functions.
Other functions include subscriber screening, IP Pool management and address mapping, QoS and PDP
context enforcement.
responsible for connecting the GPRS network to external packet switched networks such as the Internet
and X.25 networks.
The GGSN stores the current SGSN address of the user and his or her profile in its location register. The
GGSN is responsible for IP address assignment and is the default router for the connected user equipment
(UE). The GGSN also performs authentication and charging functions.
Other functions include subscriber screening, IP Pool management and address mapping, QoS and PDP
context enforcement.
• Summary
- General Packet Radio Service (GPRS)
- Connectionless
- Bill by packets
- IP-based communication, Internet access and increasing speed with 3G, HSDPA, HSUPA, etc.
- Connectionless
- Bill by packets
- IP-based communication, Internet access and increasing speed with 3G, HSDPA, HSUPA, etc.