Stoke, Inc.

Solutions : Packet Data Interworking Function

The explosion of mobile data traffic is leading to bottlenecks in the mobile infrastructure. Much of the mobile data traffic today is being driven by a rapidly growing base of cellular-enabled laptop computers. Nearly 100% of those laptops are also enabled for wireless LANs like Wi-Fi and Bluetooth. With the Stoke Session Exchange (SSX), mobile operators can avoid the growing threat of cdma/EV-DO data service bottlenecks by offloading Internet-bound laptop data traffic whenever and wherever possible to Wireless LANs.

3GPP2 defined Wireless LAN Interworking (IWLAN) to allow subscribers access to mobile operator packet data services while connecting over wireless LANs. The wireless LAN is connected to the operator network over a fixed line broadband network. 3GPP2 IWLAN standards also include functionality to allow subscribers to seamlessly transition between active wireless LAN connections and the macro cellular network. The SSX Packet Data Interworking Function (PDIF) is an integral component of cdma IWLAN solutions, providing high performance, scalable network and subscriber security, session management, moblity, and policy enforcement functions.

Enabling wireless LAN access to packet services with Stoke Session Exchange delivers numerous benefits to mobile operators including:

• Reduce data traffic loads in the RAN, backhaul and core networks by securely leveraging managed and unmanaged WLANs
• Improving services availability in buildings and homes where cellular coverage can be limited
• Delaying the expense of cell splitting to support higher densities of users and ever increasing data traffic volumes
• Delaying costly core network data services element upgrades (e.g. SGSN, GGSN) to manage a user-plane problem

Ecosystem components in IWLAN deployments include client software that initiates connectivity with the operator infrastructure using defined standards and manage radio access, a Packet Data Interworking Function, and an IP-based AAA server that interfaces with the HLR/HSS and communicates with both the mobile client and the gateway function.

The SSX provides superior PDIF implementations. Purpose-built for mobile broadband, the SSX delivers the data plane and control plane functions and capacity for high speed, high-bandwidth gateway applications in today's and tomorrow's mobile operator networks.

• Core network routing
• Session and application flow qos and policy enforcement
• Flow charging policy enforcement
• Session and context caching, distribution,
  and management
• AAA and location proxy relay agent
• Secure admission control and
  firewall & DDoS protection
• MS-PDIF tunneling, PDIF-HA tunneling
• Mobility management via MIP/FA

3GPP2 Standard PDIF
For IWLAN in 3GPP2 networks, the SSX performs the PDIF functions as defined in 3GPP2 technical specification X.S0028-200-0 "cdma2000 Packet Data Services; Wireless Local Area Network (WLAN) Interworking Access to Operator Service and Mobility." The SSX PDIF is a security gateway guarding against unauthorized access and inbound threats to the operator network. It also must keep track of and report charging events.

One additional function the SSX PDIF provides is that of Foreign Agent. 3GPP2 included specifications that allow data services subscribers to physically move between the Wireless LAN domain and the cdma2000 domain while maintaining their sessions with the services infrastructure and applications. The Foreign Agent relays new IP address information and routing to the Home Agent deeper in the network to ensure packet flow continues to the mobile device as it moves, acquiring new IP addresses.

Learn More: Read the Packet Data Interworking Function (PDIF) Solution Brief.