Dynamic Data Offloading : Connect Intelligently With ANDSF


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The arrival of varied smartphones and devices has inevitably encouraged greater data consumption.
Users are now more sophisticated and demand nothing less than best network performance. Smartphone generally accounts for higher ARPU and represents potential new revenue streams for enabling quad play services. Operators are aggressively addressing these challenges and improving the quality of their solution to retain existing customers and offering better service experience to build loyalty.

WiFi adoption as data offloading is gaining momentum as it improves user experience while lowering the cost of service providers. Correctly implemented, it can ease up to 20% of traffic with substantial impact of freeing up the spectrum and load balancing. Offloading data to WiFi hotspots is economically attractive, because many carriers already operate a substantial number of hotspots.

In this paper, we will examine how dynamic data offloading can be further optimized with 3GPP based Access Network Discovery Selection Function (ANDSF). ANDSF describes how the inter-system mobility between 3GPP systems and non-3GPP systems (ie: WLAN, WiMAX, CDMA) policies and priorities can control the conditions for which a device (UE) connects to which wireless network.

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Dynamic Data Offloading : Connect Intelligently With ANDSF

  1. 1. ry and dintgork Dis oa w cove ta Ofcces s Ne a ic D ntly with SF) A ynacmntelligeion (ANDD ne t I nctCon tion Fu c Sele www.greenpacket.com APPLICATION NOTE
  2. 2. AbstractThe arrival of varied smartphones and devices has inevitably encouraged greater data consumption.Users are now more sophisticated and demand nothing less than best network performance andwilling to switch providers at the slightest dissatisfaction. Smartphone generally accounts for higherARPU and represents potential new revenue streams for enabling quad play services. Operators areaggressively addressing these challenges and improving the quality of their solution to retain existingcustomers and offering better service experience to build loyalty.WiFi adoption as data offloading is gaining momentum as it improves user experience while loweringthe cost of service providers. Correctly implemented, it can ease up to 20% of traffic with substantialimpact of freeing up the spectrum and load balancing. Offloading data to WiFi hotspots iseconomically attractive, because many carriers already operate a substantial number of hotspots.In this paper, we will examine how dynamic data offloading can be further optimized with 3GPPbased Access Network Discovery Selection Function (ANDSF). ANDSF describes how theinter-system mobility between 3GPP systems and non-3GPP systems (ie: WLAN, WiMAX, CDMA)policies and priorities can control the conditions for which a device (UE) connects to which wirelessnetwork. Operators have the flexibility to manage context information in network discovery andselection procedures in push and/or pull mechanism with a policy management and controlcomponent as network-based and client-based solutions. The client-based implementation isdescribed with reference to applying real-time connection state and policy control. Policyenforcement and policy management is mapped more accurately with an overall knowledge of thenetwork at any given point of time. By intelligently managing the distribution of network load,congestion can be minimized. APPLICATION NOTEAPPLICATION NOTE
  3. 3. ContentsOverview 01Dynamic Data Offloading a Study Model 02 - WiFi or Femtocell - Why Introduce Dynamic Data Offload (DDO) - Data Offloading Tool - WiFi Data OffloadingAccess Network Discovery and Selection Function 07 - Where is the Intelligence in Dynamic Data OffloadingANDSF Implementation 10 - Policy Control with ANDSFValues of Dynamic Data Offloading Capability with ANDSF 12 - Prioritization of Access Based on Network Availability - Time Based Policy Control - Application Policy Control - Power Management - Traffic RoutingConclusion 14Offload Early, Connect Intelligently 15References 16APPLICATION NOTE
  4. 4. OverviewMobile networks are inherently constrained with the availability of spectrum and bandwidth to support the rapidlygrowing demands of mobile data. In a recent report by Cisco¹, it is estimated that global mobile data traffic growth willincrease by a factor of 26 times between 2010 - 2015.The way we interact with the internet is changing. The arrival of data-centric devices (eg: iPhone, Android , Blackberry),lower subscription prices, easy access to applications is driving data consumption and content like never before. Evenwith operators implementing transcoding methods to adapt smaller screen sizes, for pictures and videos , operators stillstruggle to satisfy data demands, managing congestion and improving subscriber experience.WiFi offload is an alternative method to ease the burden of bandwidth capacity. However, the methodology of offloadingcan be made either tightly-coupled or loosely coupled to the core network. In the tightly-coupled method, the networkoperator retains visibility and control over the traffic offload related to the location where traffic streams are offloaded orbypassed over the network operator and relevant policies provisioned. Overall data offloading implementation can bemore secure and comprehensive by complementing i-WLAN framework with dynamic data offloading. Furtherinformation to i-WLAN can be referenced in a previous whitepaper titled “Managing Data Offloading Securely over WLANaccess networks via I-WLAN”.Within the loosely-coupled method, data offload is unmanaged. By forcing the user onto WiFi, the network operator hasno visibility on the user traffic and not subject to the operator’s policies. The user experience associated to theaccessibility of service for example to web browsing, online shopping, downloading music or streaming video will be atrisk of un-trusted network attacks such as disclosing or tampering of user details. Other issues pertinent, which mayinvolve some form of credit card purchase. Such transactions are not subject to operator controlled service rules – sincethe user subscription relationship is decoupled from its control policy.The applied access rules previously enforced within the walled-garden parameters will be “lost” once the IP trafficbypasses the packet data network (PDN) en-route to the Internet directly. These IP traffic is identified and routed purelyon the IP address regardless of the policies enforced on the service application level. 01¹ Source: The Cisco® Visual Networking Index (VNI) Global Mobile Data Traffic Forecast Update 2011APPLICATION NOTE
  5. 5. Dynamic Data Offloading a Study ModelNetworks are generally not equally utilized at any given time. Take for example a 3G cell site in the central business districtof Kuala Lumpur during peak hours will have full utilization. The 3G cell supports up to 20 users at 14.4Mbps (assumesaverage throughput of 512kbps/user). Due to congestion, the number of user doubles to 40, but the average throughputper user is halved and continues to provide data services at sub-standard speeds with the risk of user dissatisfaction.However, another operator operating an alternative access technology (be it WiFi or WiMAX) within the vicinity ofoverlapping the 3G cell site is not fully loaded. Often, the internet bound traffic does not contribute to ARPU but occupythe network capacity. How effectively can the 3G operator capitalize on the availability of bandwidth capacity of theadjacent WiFi network to balance the network load efficiently and improve user experience?WiFi or FemtocellGiven that spectrum is a premium limited resource, operators are turning to WiFi or femto-based offload to ease trafficneeds. The stark difference between WiFi and femtocells lie in the spectrum utilization. WiFi operates in unlicensed bandwith a larger bandwidth capable of supporting data rates of 11Mbps up to 54Mbps (peak theoretical) and couples thebackhaul onto the fixed line, effectively freeing-up the 3G spectrum and improving capacity. Femtocells on the hand,operates in licensed band wirelessly over the shared air interface of 3G network. Femtocells can improve indoorcoverage, but not increase capacity.WiFi offload improves capacity at a fraction of the cost, since there is already WiFi infrastructure readily available.Dynamic Data Offloading can be initiated with an intelligent connection client in the device (UE). The device (UE) is ableto determine the subscriber state early in the network and exchange information with the policy controller in real-time toadjust network connection state. 02APPLICATION NOTE
  6. 6. Why Introduce Dynamic Data Offload (DDO)The periodic traffic surge is noticeable during peak hours. Instead of adding a second carrier on the 3G network oradding new cell sites with impacts on radio planning and so forth, operators can take advantage of dynamic data offloadearly to detect congestion and re-route the traffic to alternative WiFi access. The network selection and discoverycapability is heavily dependent on the intelligence behind connectivity. The main drivers for DDO is apparent in - Improving over the air radio capacity - Relieving transmission backhaul dependencies - Delaying CAPEX investment for network upgrade - Subscriber retention and improving user experience - Creation of new revenue streams as a result of better analysis of usage behavior - Separation of revenue generating traffic and low value bulk internet traffic - Scalability of single connection client without cost impact to backend processesData Offloading ToolGreenpacket’s Intouch Connection Management Platform (ICMP) is an easy to use, single-client connectionmanagement solution that combines device (UE) and user management. The single-client software converge multiplenetwork access and executes data offloading transparently. Incorporating customizable features and capabilities, theICMP can intelligently detect the availability of access networks based on signal strength and user policies allowed foraccessing certain data services on a cellular network (such as 3G) and if there is less congested alternative network (suchas WiFi, WiMAX, EVDO) available in the same vicinity. ICMP switchers the user from 3G to WiFi without interruption toconnectivity by ensuring a seamless user experience. As a result of the in-built intelligence, the ICMP can determine thebest available networks for data offload within the pre-loaded local policy in the absence of network policy. The addedadvantage of the make before break further enhances the seamless connection experience, without requiring a switchof different connection profiles. Figure 1: Intouch Connection Manager GUI. 03APPLICATION NOTE
  7. 7. WiFi Data OffloadingThe efficiency of offloading 3G cell to WiFi can be studied from the data rates, coverage radius and the density ofsubscribers supported. The other considerations primarily will revolve around the transmission backhaul andinstallation relevant in the CAPEX investment. Details of cost savings related to data offloading are not discussed here.Reference to a previous whitepaper “Operators Can Save $14 million Yearly Through Data Offloading”, a TCO Studydescribes it separately.The efficiency of network planning directly impacts the performance and quality of the network. There is no definednotion on the best network. Congestion is measured against how much data traffic deteriorates to affect user experiencethat is expected of the service.The support of voice service is 12bkps. Theoretically, in a given single 3G carrier at 5MHz channel bandwidth, S 111configuration, it can support up to 1,000 voice subscribers. The number of subscribers supported per cell is dependenton the radio planning parameters for a given speed and average throughput per cell. In case of a data service, theminimum data speed is 256kbps to support VoIP.For a given WiFi cell, the average cell throughput is 11Mbps (802.11a standard). It can go up to 54Mbps (802.11gstandard). The added advantage of WiFi is the greater channel bandwidth of 22MHz. Therefore, the achievable cellthroughput is higher by a factor of 4.The study of WiFi channel deployment and 3G channel deployment can be looked at the capacity efficiency. Assumingthe comparison is made on average data speeds of 512kbps for both WiFi and 3G. A typical 3G carrier can deliveraverage throughput per cell of 14.4Mbps. If under normal condition, the node B can support up to 28 subscribers atthe average 512kbps per user. Given that congestion occurs by 70% utilization, the number of active subscriberssupported per node B is approximately 20. (Active subscribers is defined as active concurrent users, excluding idleand connected subscribers)In WiFi (802.11 a), there are up to 3 non-overlapping channels. Therefore, the total throughput achievable is up to33Mbps. At 70% utilization, the active subscribers supported per WiFi cell is approximately 45. The capacity supportedis 55% greater than a 3G node B. Operator owned WiFi and Partner WiFi Operators that have aggressively embraced a WiFi offloading strategy, such as PCCW and AT&T Mobility, estimate that about 20 % of their overall data traffic is over WiFi networks. In cases where operators do not operate WiFi networks but extends its coverage often partner a 3rd party WiFi provider. Such wholesale method to support the additional traffic for a fixed cost is a feasible option with no direct impact to the existing infrastructure and backhaul requirements. With the acquisition of Wayport, AT&T expanded its WiFi network to offload traffic from its cellular network as a network growth strategy. With coverage of 85%, it is an example of a successful WiFi offload strategy to ease the burden on its 3G mobile broadband where the carrier has suffered as a result of iPhone driving data usage. Most* of AT&Ts smartphones now support auto-authentication at the carriers AT&T-affiliated WiFi hotspots, which number more than 23,000-- WiFi usage does not count against a subscribers monthly smartphone data usage plan. *source: Wi-Fi offload for mobile networks: 20% of traffic and counting FierceBroadbandWireless http://www.fiercebroadbandwireless.com/special-reports/ 04 wi-fi-offload-mobile-networks-20-traffic-and-counting#ixzz1MsZdbugdAPPLICATION NOTE
  8. 8. Site Count 40 35 30 25 20 15 10 5 0 3G WiFi Supports up to 20 Supports up to 45 active users per site active users per site Figure 2: WiFi and 3G Site Count Study for average user throughput of 512kbps.In terms of the coverage, a 3G cell range is up to 5 times of a typical WiFi cell range. Within a dense urban morphology,a 3G cell range can vary between 1-2km. (cell ranges are inter-dependent on radio planning parameters such as variousmodulation schemes, terrain, density of subscribers, achievable speeds. This assumes the average vehicular speed of30km/hour). On the contrary, WiFi cell range vary between 100-200m, equating to more WiFi APs per km2 coverageradius. Despite WiFi cell range of 5 times less than a 3G node B (for every 1km, 5 WiFi APs are required), the trade-off ofcell capacity is far greater.If for example the density per area is 1,000 users (assumes single device (UE), single user)per 1km2 radius with 70%active users; the 700 active subscribers requires up to 35 3G cell sites to support. However, with WiFi the number of cellsites is 55% less at 16. A typical WiFi AP cost is around USD100-200, while a 3G node B is USD30,000². For anequivalent number of cell sites, the CAPEX savings are significant. Instead of deploying more node Bs, operators canleverage on the WiFi network within the vicinity as means of extending its coverage and relieving heavy internet trafficduring or off peak hours.² Average node B of S111 configuration in emerging markets. 05APPLICATION NOTE
  9. 9. Additional Base Station Increasing Cost WiFi AP 55% greater capacity Increasing Capacity Figure 3: Cost Comparison of WiFi AP and 3G Node B.WiFi architecture exhibits significantly higher data rates than 3G and it could be easily modified to increase the numberof connection to open or partner WiFi network with the presence of a WiFi AP. 3G provides continuous connectivityover further cell range, with lower data rates and relatively high cost while WiFi is intermittent with high bursts of data(other consideration excluded in this study includes the impact of backhaul, leasing of transport network andinstallation works).With better control over data offload solutions, such as dynamic data offload via Access Network Discovery andSelection Function (ANDSF), operators can understand the user state and commensurate network state contributing tocongestion. Most importantly, it detects the source of congestion trigger and resolves the issue early, before it affects theservice experience. The intelligent ANDSF enabled connection client can push connection status with granularity suchas location corresponding to cell ID or SSID to the Policy Charging and Rules Function³ (PCRF). The PCRF performreal-time policy response network state at applications to identify the congestion point. Each service stream can be easilyidentified by the IP address where it originates and the destination IP. By having a direct connection to PCRF, the policyinformation is pulled by the ANDSF connection client to determine whether a handoff is necessary to maintain theconnection as applied in the examples above.³ The PCRF server in this instance is 3GPP ANDSF standard compliant. ANDSF module can 06 exist independently or implemented within proprietary policy control and management server that may comprise of several functional modules, depending on the network architecture.APPLICATION NOTE
  10. 10. Access Network Discovery and Selection FunctionAccess Network Discovery and Selection Function (ANDSF) is a 3GPP standard defined in TS 22.278, TS23.402 andTS24.312 specifications through which the operator can provide inter-system mobility policies and priorities to controlwhere and when, the conditions for which a device (UE) connects to which wireless network. It supports theinter-working solution between 3GPP networks and non-3GPP access (ie: CDMA, WiMAX, WLAN) combiningnetwork-based and client-based solutions for both trusted and un-trusted non-3GPP access networks.For operators which have both WiFi and 3GPP infrastructures, it is possible to use ANDSF to implement dynamic dataoffload. Dynamic data offload can complement WiFi data offloading in a structured method. Within ANDSF, the contextof offload can be made more accurately at the user level ie: bearer-aware and closely coupled to the policy managementand control component4 (eg: PCRF server). Instead of relying heavily on the policies enforced at the core network(backend), actual decision making process can be made real-time as a result of direct relation to the user activity at thedevice (UE).The motivation for implementing ANDSF is largely driven by the need for better bandwidth utilization. Bandwidthutilization is highly relevant to the control and optimization for mission critical applications like VoIP, P2P streaming andvideo streaming.In the following sections, we will discuss the impacts of applying intelligence in data offloading, where operators have theflexibility to manage context information in network discovery and selection procedures in push and/or pull mechanismwith a policy management and control component. The study of ANDSF will be described from a client-basedimplementation on the device (UE). Operators controlled and service-aware selection of wireless networks can bringbenefits to the operator looking to offload using WiFi. The ability to retain visibility of which IP traffic is routed over WLAN(eg: best effort internet traffic like email, web browsing, which are non-revenue generating) and which IP traffic ismaintained on the 3G link (eg: VoIP that is quality sensitive). This may contribute to better understanding of the trafficmodels relevant to minimizing congestion. 074 Policy management and control component is used interchangeably with PCRF in this application note.APPLICATION NOTE
  11. 11. Where is the Intelligence in Dynamic Data OffloadingToday’s network is mixed with dual radio scenarios, such as WLAN and 3GPP based networks (ie: WiFi-3G). The twoaccess networks are not “aware” of each other. It lacks the intelligence to control the access network of the device (UE)state in the other access network. Given that WLAN is not a “controlled” access network and works in unlicensedspectrum the only network condition of radio quality and the performance through that WLAN is made available only tothe device (UE). Hence, the device (UE) is better positioned to decide the connectivity options. Most often, the networkselection is managed by a connection manager in the device (UE). Connection Manager Policy Controller Internet Mobile Broadband Operator Core Network (3G UMTS) Each Network Policy includes: • Access Technology Type (3G, WiFi) • Network Discovery List (3G, WiFi SSID) • Access Network Priority • Policy Validity (8 hours) • Location Figure 4: Dynamic Data Offload with ANDSF. 08APPLICATION NOTE
  12. 12. Default connection at RAN may not always be most optimal at a given point in time from core network connectivity, theend-user, application or service perspective. However, intelligent connection managers allow it to search and prioritizethe best available connection based on pre-defined requirements such as signal strength and operator policies. In thismanner, intelligent resource management provides a cost-effective way to support the data traffic by optimizing networkradio resource, balancing the network load, reducing network congestion and delaying CAPEX for future upgrades.ANDSF may provide a list of access networks available in the vicinity of the device (UE) for all the available accesstechnology types requested by the device (UE). Instead of unnecessary background scanning, the ANDSF connectionmonitoring may be carried out to handover or perform cell selection/re-selection measurements in which the device (UE)monitors the received signal strength indicator signal levels (RSSI) received from different base stations. This reduces thebattery drain on the device (UE) without continuously scanning in the background.By selectively triggering the connection of device (UE) to a given threshold or the preferred available access networktypes based on inter-system mobility policies, the network load can be balanced or spread out to the availability ofnetwork radio resource at the point where congestion is likely to occur. Once the device (UE) receives the policyrelevant to location and validity of time interval, the ANDSF will apply the current conditions to match the policy.Policies can be tailored for different access networks, regardless of devices (UE) to enable seamless connectivityexperience. In the longer term, effective access network monitoring can reduce the pressure of CAPEX upgrades tosustain the increased capacity.The added intelligence of ANDSF brings benefit to the negotiation of connection state by various operator policiessupported as• Location-Aware Policy – cell ID or associated SSID is checked against the policy database for specific locations that are preferred/relevant• Access Network Discovery Policy – list of available access networks(RAT type) that are available within the vicinity and facilitation of prioritized access network selection for network handover• Time-based Policy – configuration of policy validity “time to live” interval to current location and profile• Subscriber-based Policy – dynamic allocation of subscriber package and profile 09WHITEPAPER NOTEAPPLICATION
  13. 13. ANDSF ImplementationPolicy Control with ANDSFAlthough operators are increasingly looking at using WiFi for offload in congested areas, it risks losing visibility over trafficpolicies that were configured for the user once it routes through WiFi. What is lacking is a way for the network tocommunicate to users (applications and/or websites they are using) a real-time or predicted measure of the network’scongestion levels.ANDSF keeps a direct relationship to the core network by providing dynamic provision of information to the device (UE)for network discovery and selection procedures related to non-3GPP accesses; the ANDSF connection client can pulland/or with a combination of pull-push may be supported with the policy charging and rules function (PCRF). ANDSFcomplements both the PCRF and Deep Packet Inspection (DPI) module. By means of direct device (UE) communicationat applications level towards the PCRF, the ANDSF provides indication to the device (UE) on the selection of network byreducing over the air processing required in the device (UE) to establish the wireless link. Connection Policy Control Manager Server Server Application Pull relevant Server connection policy, cell-ID, time Subscriber Push policy decision database server based on location, subscriber entitlement, application type ANDSF client in CM GGSN / PDSN Internet 3GPP Access 3G Network WAG Non-3GPP Access Figure 5: ANDSF Architecture 10APPLICATION NOTE
  14. 14. Detecting users, locations, applications or device (UE) type is crucial in determining the conditions for triggering offload,and under what circumstances. Increasingly, applications and devices (UE) are becoming more aware of their context –what network they are connected to, what is the state of performance of the network and so forth for a given time andlocation.The ANDSF connection client pull subscriber state information (location based cell ID, preconfigured policies and timeconfigurable connection policy), from the PCRF. The ANDSF connection client will check the existing policy. If the policyis alive, it applies the current policy. Otherwise, the ANDSF connection client will request for a new policy. Similarly, thebusiness rule engine in the PCRF pushes dynamic and subscriber specific policy decisions by checking the subscriberspecific data (eg: subscriber package, access entitlement/restriction) accordingly.Based on this information, PCRF dynamically modifies the connection policy rule depending on the type of policy controlrequired, acting as a policy management point. The policy decisions are delimited by validity of the location, time of dayand discovery information. The ANDSF connection client is an intelligent module that learns of subscriber state andnetwork state parameters over time to detect the corresponding bearer (WiFi, 3G, WiMAX) to the suitability of context(service, device type) connection. These parameters ensure that the operator retains visibility of which IP traffic arecritical and retained on the 3G or WiFi connection.Through connection shifts based on context information and by combining knowledge about real-time network levels,applications and devices (past data usage history), gives greater control on offload strategy rather than a single isolatedmeasurement of the radio conditions. By re-prioritizing subscribers on a congested cell site or offload all mobile datatraffic or laptop to WiFi, during peak congestion periods, specific times of day, days, weeks or combination of them,operators can have the flexibility of controlling bandwidth, QoS availability and application-specific service correspondingto service level agreements. 11APPLICATION NOTE
  15. 15. Values of Dynamic Data Offloading Capability with ANDSFPrioritization of Access Based on Network AvailabilityDuring network selection process, the ANDSF can provide a list of access networks available in the vicinity of the device(UE). The configurable network access discovery is facilitated by the ANDSF connection client that interacts with thePCRF at the application level communication. Dynamic discovery information of location by ANDSF connection client iscommunicated to the device (UE) in a pull mechanism.The PCRF provides information and policies on the neighboring cells to determine when to offload traffic or triggered dueto congestion. By means of prioritization of congested networks, the PCRF pushes decisions to the device (UE) via theANDSF connection client to manage congestion at per subscriber level or per cell level connection. In data offloading,the intelligent policy control information exchange with ANDSF complements the offload decisions based on theavailability of WiFi networks in range or otherwise.Time Based Policy ControlThe device (UE) initiated connection switching is a carried out by ANDSF connection client. The ANDSF connection clientdownloads the user policy relevant to location, connection policy and configurable “time to live” policy - matching itlocally to the pre-provisioned operator policy. If the connection policy is alive, it applies the current policy. In case of thenear expiry or already expired, the ANDSF connection client will request for new policy from the PCRF.Upon receiving the newly generated connection policy from PCRF, the ANDSF connection client replaces the existingpolicy with the new policy and the re-prioritized access network list comes into effect until expiry (ie: if switched from3G to WiFi, the ANDSF connection client shall not connect to 3G network until expiry of policy or change of location).In case of failure to update policy, the ANDSF connection client can apply the localized rule manager within accordingto priority, best performance or most economic policy (eg: ANDSF connection client’s connection policy is configuredto WiFi by default). 12APPLICATION NOTE
  16. 16. Application Policy Control5The PCRF supports time based metering and subscriber based policy for fair usage control. Take for example a cappedpostpaid fair usage plan. Operators usually enforce an average bandwidth threshold policy with flexibility of some burstaccess. Through the adaptive policy control approach of the PCRF, the operator has continuous access to real-timeinformation about the subscriber’s behavior, collected throughout the session.If high level of traffic is continuously sustained over the aggregate total usage volume (daily/weekly/monthly) and thesubscriber policy is breached, it may trigger the PCRF to generate a new policy decision based on subscriber specificdata such as data plan/package, access entitlement and usage pattern. Similarly, the ANDSF connection client (at theper cell-level connection or per subscriber level) interacts with the PCRF data offload module by pushing the availableSSID list within the vicinity to the PCRF access to network bandwidth resources accordingly. As a result, the selectivedata-offload is invoked with a re-ordered SSID list. The service level is downgraded to the next service tier to protect thenetwork against abuse until the congestion subsides. Alternatively, the PCRF can also trigger alert notice to upgrade tothe next service tier subject to charge difference, depending on the implementation configured.This approach enables the operator to distinguish between temporary, unexpected increases in subscriber traffic andnetwork abuse. The mechanisms which context awareness from the perspective of PCRF can facilitate policyenforcement through the device (UE) include configuring WiFi on/off directive and forcing offload through the ANDSFconnection client.Power ManagementThe network discovery and selection has been an issue from a device (UE) perspective, because of battery consumptionand turning on and off two radios simultaneously. With real-time network congestion state information from ANDSFserver, the ANDSF connection client may employ the policy to avoid unnecessary background scan by the device (UE)to prolong battery life. Different access networks have different effects on the speed and connection establishment timethat affects the intensity of battery consumption. The access network selection process can be made more efficient withthe ANDSF ordered access network list.Traffic RoutingOperators routing traffic directly to the Internet as a result of offloading, loose the visibility of control over the subscriberpolicies. With a managed data offload approach, operators can have visibility of IP traffic which is routed over WLAN (eg:best effort internet traffic) and which IP traffic is maintained on the 3G link (eg: VoIP). The combination of PCRF, DPI andANDSF to conduct granular data offload, ensures traffic routing across the network allocated to particular services canbe optimized for specific bearer types. By having the visibility of IP traffic, operator can analyze user behavior related tothe bulk of IP traffic generated. The added intelligence can be applied in user segmentation and creation of new servicestreams to segregate high ARPU potentials, moderate users and low bandwidth users.5 Application policy control is part of the ANDSF standard. The deployment is proprietary, depending on the implementation of the ANDSF server and network architecture. 13 Greenpacket ANDSF client is currently testing the functional attribute with select vendors. (vendor names are withheld due to non disclosure agreement in effect)APPLICATION NOTE
  17. 17. ConclusionWi-Fi is suited for data offload as echoed in AT&T and PCCW’s business model. Today millions of subscribers arealready using WiFi as their primary source for data/internet access whether as part of their subscription plan or a freeservice. As observed, WiFi has played a role in relieving congestion, but at the same time generating more usage.The implementation of Dynamic Data Offloading via ANDSF can further enhance the both the 3G and WiFi experience.Dynamic data offloading is necessary to minimize congestion. The earlier a congestion trigger is controlled and managedthe operator can continue to improve the distribution of network resources from the perspective of spectrum planning.Since networks do not behave identically nor follow the same traffic model, data offloading exercise can facilitatebalancing the load whenever congestion occurs. Policy enforcement and policy management is mapped moreaccurately with an overall knowledge of the network at any given point of time, rather than a silo representation at theaggregation point at the backend. More and more operators are embracing data offloading as means to satisfy thebandwidth requirements. With dynamic data offloading methodology, the operators can capitalize on extending itsnetwork, while maintaining a balanced network investment. 14APPLICATION NOTE
  18. 18. Offload Early, Connect IntelligentlyGreenpacket welcomes you to embark on dynamic data offloading today with ANDSF for optimizing your networkoperations. At Greenpacket, we understand the demands placed on Operators like you. Our solutions are designed to giveyou the flexibility to constantly deliver cutting-edge offerings without exhausting your capital and operating expenditures.With Greenpacket, limitless freedom begins now!Free ConsultationIf you would like a free consultation on how you can apply data offloading with ANDSF, feel free to contact us atmarketing.gp@greenpacket.com. Kindly quote the reference code, SAP0611 when you contact us. 15APPLICATION NOTE
  19. 19. References1. The Cisco® Visual Networking Index (VNI) Global Mobile Data Traffic Forecast Update 2011.2. The Role of Adaptive Policy Control and Smart Caps in Managing Mobile Data Growth.3. 3GPP TS 23.402 V8.03. Bearer-aware policy management and charging, Disruptive Analysis, Dean Bubley. 16APPLICATION NOTE
  20. 20. About Green Packet Greenpacket is the international arm of the Green Packet Berhad group of companies which is listed on the Main Board of the Malaysian Bourse. Founded in San Francisco’s Silicon Valley in 2000 and now headquartered in Kuala Lumpur, Malaysia, Greenpacket has a presence in 9 countries and is continuously expanding to be near its customers and in readiness for new markets. We are a leading developer of Next Generation Mobile Broadband and Networking Solutions for Telecommunications Operators across the globe. Our mission is to provide seamless and unified platforms for the delivery of user-centric multimedia communications services regardless of the nature and availability of backbone infrastructures. At Greenpacket, we pride ourselves on being constantly at the forefront of technology. Our leading carrier-grade solutions and award-winning consumer devices help Telecommunications Operators open new avenues, meet new demands, and enrich the lifestyles of their subscribers, while forging new relationships. We see a future of limitless freedom in wireless communications and continuously commit to meeting the needs of our customers with leading edge solutions. With product development centers in USA, Shanghai, and Taiwan, we are on the cutting edge of new developments in 4G (particularly WiMAX and LTE), as well as in software advancement. Our leadership position in the Telco industry is further enhanced by our strategic alliances with leading industry players. Additionally, our award-winning WiMAX modems have successfully completed interoperability tests with major WiMAX players and are being used by the world’s largest WiMAX Operators. We are also the leading carrier solutions provider in APAC catering to both 4G and 3G networks. For more information, visit: www.greenpacket.com.San Francisco · Kuala Lumpur · Singapore · Shanghai · Taiwan · Sydney · Bahrain · Bangkok · Hong Kong Associate MemberCopyright © 2001-2011 Green Packet Berhad. All rights reserved. No part of this publication may be reproduced, transmitted, transcribed, stored in a retrieval system, or translated into any language, in any formby any means, without the written permission of Green Packet Berhad. Green Packet Berhad reserves the right to modify or discontinue any product or piece of literature at anytime without prior notice.