International Journal of Scientific Engineering and Technology ISSN:2277-1581 Volume No.5 Issue No.7, pp: 389-393 01 July 2016 IJSET@2016 doi : 10.17950/ijset/v5s7/704 Page 389 Classification and Flow Control in PGW D. Sujini 1 , Deva Kumar 2 , Ramana Ravuri 3 1,2 VFSTR University, Vadlamudi, Guntur-Dt, Andhra Pradesh, India, 522213 3 Resonous Technologies Pvt Ltd ,Bangalore e-mail: sujidodda523@gmail.com 1 , deva.248@gmail.com 2 , ramanaravuripmp@gmail.com 3 Abstract— PDN Gateway(PGW) is one of the major module in EPC system. PGW is exit and entry point in LTE for ingress and egress data traffic packets of UE, which connects UE to external PDN.For downlink data received from Packet data networks (PDN), should be classified based on IP headers and apply classification Rules. In the downlink, ingress IP packets destined for different UEs, are classiffied by PGW and forward to respective QoS-based bearers of respective UEs.Traffic Flow Templates (TFTs) are assigned to each QoS-bearer, classification is performed based on these TFTs.Each GBR bearer is assigned with QoS parameters, PGW uses these QoS for performing flowcontrol.Irrespective of incoming rate, flow has to be controlled and sent to mobile as per the QoS rule.Here we are using token bucket algorithm for flow control.This paper reviews how Classification and Flowcontrol done in PGW. Keywords – TFT, Bearer,UE,PGW,GBR,PDN. . I. INTRODUCTION LTE is standardized by 3rd Generation Partnership Program(3GPP) to address the needs of growing demand for high speed connectivity for applications like mobile TV,video streaming,online gaming etc. Long Term Evolution (LTE) network architecture is designed based on IP connectivity, to provide seamless connectivity between different elements, PDN, PGW, SGW, MME, HSS, PCRF and eNodeB. MME, SGW, PGW and HSS form the EPC, Enhanced packet core, which is backbone for LTE. It supports 150 Mbps downlink and 75 Mbps uplink for the end customer. LTE supports both FDD and TDD wireless technologies. FDD required two bands one for each uplink and down link. TDD uses single frequency for uplink and downlink at different timing slots. There are different frequencies allocated to FDD and TDD. So far worldwide 32 band frequencies are allocated for FDD and 12 bands for TDD. It interops with existing wireless technologies such as GSM,GPRS and WCDMA. LTE networks are deployed worldwide to address the growing demand of mobile broadband services. II. EPS BEARER STRUCTURE The EPS bearers are used to deliver the traffic over LTE. EPS bearer is logical connection between the UE and PGW for every network connection. Bearer is nothing but the virtual path to deliver the traffic. Different bearers have the different QoS service.The data flows delivered on the same EPS bearer will get the same QoS service.There are two types of bearers in EPS system,they are default bearers and dedicated bearers.The default bearer is established during the initial attach procedure of UE and the default bearer does not contain the traffic flow template (TFT). The default bearer will provides the best effort service. A dedicated bearer is established on demand[2],whenever the user wants to get sevices like internet, which need higher QoS than the default bearer,through which user is currently getting service.UE can connect with more than one PDN gateway, which has one mandatory default EPS bearer and may have zero or more dedicated bearers.The maximum number of EPS bearers which UE can have is 11. Different applications require the different QoS requirements, To meet the requirement of different QoS services the dedicated bearers are established.We have different TFTs for uplink and downlink.The PGW contains the downlink traffic flow templates and UE contains the uplink traffic flow templates.TFT associates with the packet filters(PF). Every packet filter associated with the traffic flow template corresponds to a particular dedicated bearer.The ingress IP data flow is classified into different SDFs based on the packet filters and send it to corresponding bearer for the transmission. The SDFs with the same QoS can transmit in same EPS bearer,all the packet filters corresponding to the EPS bearer are included in the traffic flow template(TFT) of that bearer.Every packet filter have the unique identity to map with the corresponding bearer.Fig.1 describes the structure of EPS bearer,TFTs and SDFs. Fig.1. Mapping of Datastreams to EPS bearer III. TRAFFIC FLOW TEMPLATE IN EPS BEARER An operator of LTE, provides different QoS services to its end customers, i.e subscribers of LTE services. Many subscriptions levels with different QoS, are defined based on the magnitude of subscribers and their service usage for internet, voice, video