Supporting Nodes SGSNserving GPRS supporting Node Functions 1Packet

Supporting Nodes • SGSN(serving GPRS supporting Node) Functions 1]Packet switching 2]Routing and transfer 3]Mobility Management 4]Logical Link management 5]Authentication 6]Charging

Supporting Nodes • GGSN(Gateway GPRS support Node) Function 1]It acts as an interface between GPRS backbone network and external packet data network 2]It maintain routing information that is necessary to route (PDU) of SGSN mobile user 3]Translation It stores the current SGSN address of the user and his profile in its location register. 4]Authentication and charging function

GPRS Network Enhancements • Bss. BTS upgrade to allow transportation of user data to the SGSN also the BTS needs to upgrade to support packet data transportation between the BTS and the Ms over the air interface • Home Location Information HLR needs enhancement to register GPRS user profiles and respond to queries originating from GSNs • MS

• Network Layer • (IP or X. 25) • Relay • SNDCP GTP • • LLC • TCP/UDP • • Relay • RLC TCP/UDP BSSP • BSSGP IP • MAC • Network Service • Network • Service Data Link Service • Data Link • Layer • PLL • RFL Phy Layer • Phy layer • Gm • BSS • RLC : Radio link control • PLL : Physical link layer • RFL : Physical RF layer • MAC: Medium access control • • Gb • GGSN • SGSN BSSGP: BSS GPRS Application protocol GTP : GPRS tunneling protocol TCP : Transmission control protocol UDP : user datagram protocol IP : Internet Protocol • Transmission Plane • Gi

• MS • BSS • Application • Network Layer • SNDCP • LLC • RLC • MAC • PLL • RFL • Relay • RLC • MAC • • PLL • • RFL • Um • SNDCP: Subnetwork dependent • convergence protocol • LLC : Logical link control • RLC : Radio link control BSSGP Network Service PHY Layer

Signaling plane • The protocol architecture of the signaling plane consist protocol used to control and support the function of transmission plane • It includes signaling information about 1]GPRS attach and detach 2]PDP context activation 3]Control of routing paths 4]Allocation of new resources

Signaling plane • MAP-Mobile application part(extension to SS 7 of GSM) Communication between SGSN and HLR or EIR Used to transfer signaling information related to location updates, user profiles and handovers, routing information, • BSSAP(Base station system Application part+) Used to transfer signaling information between the SGSN and the VLR

Transmission plane Consist following interfaces 1]GPRS Backbone 2]BSS-SGSN Interface 3]Air interface

GPRS Backbone • It is transmission between SGSN and GGSN • User data packets and related signaling information within the GPRS n/w are encapsulated using the GPRS Tunneling protocol(GTP) • It Is used in both intra-PLMN and inter PLMN • GTP packets carry the users data packets from both IP and X. 25 data n/w

GPRS Backbone • Below GTP the standard protocol TCP or UDP are used to transport the GTP packets within the backbone n/w • Ethernet, ISDN or ATM based protocol may be used in the physical layer • In GPRS backbone we have IP/X. 25 -over GTPover-UDP/TCP-over IP transport architecture

BSS-SGSN Interface • It is divided in to following protocols 1]Sub-N/w Dependant Convergence Protocol. The SNDCP is used to transfer data packets between SGSN and MS its functionality includes multiplexing, segmentation, compression and decompression of user data

BSS-SGSN Interface • Logical Link Control-LLC This layer assures the reliable transfer of user data across a wireless n/w Base station system GPRS protocol(BSSGP) Delivers routing and QOS related information between BSS and SGSN N/W service -This maps BSSGPS service request to the appropriate frame relay service

Air Interface • The air interface defines physical and data link layer • Data link layer: -the data link layer between the MS and the BSS is devided into three sublayers • 1]LLC • 2]RLC • 3]MAC

• LLC-this layer provides a reliable logical link between an MS and its assigned SGSN • RLC-estabilish reliable link between MS and BSS this include the segmentation and reassembly • MAC-Acess Control

Physical Layer Physical Link Layer • Data encoding • Data unit framing • Detection and correction of physical medium transmission errors. Physical RF layer-Modulation and demodulation

GPRS operations-1] GPRS Attach and detach When a MS is turned on, the first function it performs is GPRS attach It must register with an SGSN of the n/w It implements logical link between MS and SGSN N/w checks if the MS is authorised to use the service if yes it copies the user profile from the HLR to the SGSN) SGSN assigns a packet temporary Mobile subscriber identity(PTMSI) to the MS After successful GPRS attach mobile station must apply for an address to exchange the data for external network Ex. If PDN is IP-IP address This address is called PDP(Packet data protocol address) For each session PDP context is created it contains PDP type, requested. QOS, GGSN address. This context stored in MS, SGSN, GGSN

• PDP Context Procedures GGSN MS initiated BSS � � SGSN GGSN � � Packets from ext. nw. � PDU notification req. � PDU notification resp. � Request PDP Context activation � Create PDP Context Request � Activate PDP Context Request � � Create PDP Context � Response � Activate PDP Context Accept �

• PDP address can be static or dynamic • PDP c • context activation procedure • The disconnection from GPRS network is called GPRS detach all the resources are released detach process can be initiated by the mobile station or by the network

Mobility Management • As a mobile station moves from one area to another mobility management functions are used. to track the location of MS within each PLMN. • SGSNS communicate with each other to update the MS s location in the relevant registers

Mobility Management • The mobile stations profiles are preserved in the VLRs that are accessible to SGSN via local MSC. • A logical link is established between MS and the SGSN at each PLMN • When MS moves from SGSN area the logical link is released.

Routing GSM Location Area(LA) is divided into several Routing Areas(RA) RA consists of several cells SGSN is informed when MS moves to a new RA MS sends a “Routing Area Update Request” to its assigned SGSN

Routing When an MS that is in an active or a standby state moves from one routing area to another within the service area of one SGSN, it must perform a routing update. The routing area information in the SGSN is updated, and the success of the procedure is indicated in the response message.

Routing A cell-based routing update procedure is invoked when an active MS enters a new cell. The MS sends a short message containing the identity of the MS and its new location through GPRS channels to its current SGSN. This procedure is used only when the MS is in the active state.

Routing The inter-SGSN routing update is the most complicated routing update. The MS changes from one SGSN area to another, and it must establish a new connection to a new SGSN. This means creating a new logical link context between the MS and the new SGSN and informing the GGSN about the new location of the MS.

Routing Intra SGSN Routing Area Update Inter SGSN Routing Area Update

Data services in GPRS services are usually used in two modes • Application Mode • Tunneling mode • Application mode 1]in this mode the user will be using the GPRS mobile phone to access the applications running on the phone itself 2]all GPRS phone have WAP browser as an embedded application it allow to browse WAP sites

Data services in GPRS Some GPRS devices support mobile execution environment to develop a client application that run on the device These environments are Symbian and J 2 ME and application are developed in C, C++, java. 2]Tunneling mode. This mode is for mobile computing where the user will use the GPRS interface as an access to the network The mobile phone will be connected to the device like laptop or pda used as a modem to acess the wireless data network

GPRS hanset(device) GPRS terminal can be of three classes Class. A=a terminal support GPRS data and other GSM services such as SMS and voice simultaneously. SMS can be received while a voice or data call is in progress. Class B =terminal can monitor GSM and GPRS channel simultaneously but support only one of these service simultaniously and other service is on hold. SMS can be received while a voice or data call is in progress. Class C=terminal support only non simultaneous attach terminal can make or receive calls from only the manully selected network services the service that is not selected is not reachable.

GPRS hanset(device) Each handset will have a unique form factor with a numeric keypad and small display, colour display with camerabuilt in voice and web browsing capability, icon drive screen.

GPRS bearer services Bearer services of GPRS offer end-to-end packet switched data transfer. SMS-Short Message Service WAP-Wireless Application Protocol MMS-Multimedia messaging Service

GPRS Application Generic Application. Information service, internet access, email, web browsing, sports score, wheather, flight information, news headlines, prayer reminders, lottery results, jokes, horoscopes, traffic information, banking over wireless GPRS specific applications 1]chat 2]Multimedia service 3]VPN-many bank ATM machines use GPRS based networks to connect ATM system with the banks server