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Mobile Wireless Exponential Growth of World Wide GSM Data Users in million subscriber Growth in mobile data is expected to be 70% p.a. in next 5 yrs 90 80 70 60 50 40 30 20 10 0 innovators early adaptors early majority (Merryl Lynch) Late majority ~ 1% 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 N+I_2k © 2000, Peter Tomsu 01_mobile_wirel 2 Dramatic Increase of Mobile Data Volume UMTS study funded by the European Comission Mbytes per user per month data will account for up to 75% of total mobile traffic by 2005 up to 40% of people in the EU will be using mobile phones 35 30 25 20 Today 0.8 Mb/user/month 15 10 5 0 1995 N+I_2k 1996 © 2000, Peter Tomsu 1997 1998 1999 2000 2001 01_mobile_wirel 2002 2003 2004 2005 3 Wireless Data Network Drivers • Information access • PDAs • Network computers • Alpha paging, information distribution • Web/WAP technology N+I_2k © 2000, Peter Tomsu 01_mobile_wirel 4 Services Most Often Requested After Basic Wireless Telephony Service Call Forwarding 37% Paging 33% Internet/E-mail 24% Traffic/Weather 15% Conference Calling 13% News Data Applications 3% Source: CTIA Web Page Peter D. Hart Research Associates, March 1997 N+I_2k © 2000, Peter Tomsu 01_mobile_wirel 5 Data Services on Cellular • Standards for packet services on cellular are already defined GSM: GPRS - GSM Packet Radio System CDMA: IWF and MobileIP • Both utilize bandwidth over the backhaul/backbone to gateway devices • A data network built for packet data transport can reduce the need to expand the backbone beyond voice requirements N+I_2k © 2000, Peter Tomsu 01_mobile_wirel 6 Wireless Market Segments Wireless Market Segments & Partners Wireless Internetworking Overview Residential/ Premise/ Campus Fixed Mobile Broadband Multiservice IEEE 802.11 BLUE TOOTH MMDS LMDS Cisco/ Bosch N+I_2k © 2000, Peter Tomsu 01_mobile_wirel 2G+ Cellular 3G Cellular Data Services Packet Data/Voice GPRS Mobile IP UMTS 7 Residential WLANs • Found in office environment for wireless network access • Either infrared or radio • Standards are Bluetooth IEEE 802.11 N+I_2k © 2000, Peter Tomsu 01_mobile_wirel 8 Fixed Wireless • Provide high speed wireless link to connect remote sites • Point-to-point or point-to-multipoint • Line-of-sight or non-line-of-sight systems • Two standards LMDS – Local Multipoint Distribution System MMDS N+I_2k © 2000, Peter Tomsu 01_mobile_wirel 9 Mobile Wireless Networks • Usually digital cellular radion networks • Provide voice and data services • 1G – analog transmission • 2G – digital cellular networks (like GSM) Circuit switched • 2G+ HSCSD (circuit switched bundeled timeslots) GPRS (voice CS, data PS) • 3G – like UMTS Completely packet switched voice and data N+I_2k © 2000, Peter Tomsu 01_mobile_wirel 10 GPRS and other Mobile Wireless Technologies Technology Type Throughput Investment Std. Body Availability GSM data Circuit 9.6 kbits/s Low ETSI Now HSCSD Circuit 56 kbits/s Medium ETSI 1999-2000 EDGE Packet 380 kbits/s Medium Ericsson 2000-2001 GPRS Packet 150 kbits/s Medium ETSI UMTS Packet HSCSD EDGE GPRS UMTS N+I_2k © 2000, Peter Tomsu … … … … 2 Mbits/s High (radio) ETSI 2000-2001 2002 High Speed Circuit Switched Data Enhanced Data Rate for GSM Evolution General Packet Radio Service Universal Mobile Telephone Service 01_mobile_wirel 11 GSM Packet Data Service Options • Two services as part of "Phase 2+" of the GSM specification High Speed Circuit Switched Data (HSCSD) General Packet Radio Service (GPRS) N+I_2k © 2000, Peter Tomsu 01_mobile_wirel 12 High Speed Circuit Switched Data (HSCSD) • allows the combination of multiple timeslots • Channels can be multiplexed together to offer a data rate of up to 56 Kbit/s when using all four slots (14.4 Kbs/channel) • because each time slot could carry a conventional conversation, the use of multiple slots restricts the capacity for speech traffic, resulting in the handset user specifying a minimum acceptable data rate and a preferred (and usually higher) data rate • will prove particularly useful for applications with highspeed data requirements, such as large-scale file transfers, advanced fax services and mobile video communications N+I_2k © 2000, Peter Tomsu 01_mobile_wirel 13 General Packet Radio Service (GPRS) • available over GSM networks • Data is packet switched - voice remains circuit switched • may also be supported as part of other standards, such as DECT and TDMA • based on the transportation and routing of packetized data • Capacity limitation is hence in terms of the amount of data being transmitted rather than the time of connection • reduces the time spent setting up and taking down connections • works with public data networks using Internet protocol & X.25 • "bursty" applications such as e-mail, traffic telematics, telemetry, broadcast services, and Web browsing • requires modifications to the GSM system architecture and has targeted commercial availability in the 1999 timeframe N+I_2k © 2000, Peter Tomsu 01_mobile_wirel 14 HSCSD vs GPRS • HSCSD is a small market • HSCD doesn’t do anything to ease spectrum capacity constraints that operators are facing • GPRS benefits ultimately, higher speed data the packet data element is most important because it uses the spectrum in a better way not tying up a whole channel end-to-end for one user N+I_2k © 2000, Peter Tomsu 01_mobile_wirel 15 Enhanced Data Rate for GSM Evolution (EDGE) •GSM Standard bodies are defining data networking technologies which will build upon GPRS •One such technology is Enhanced Data Rate for GSM Evolution (EDGE) •EDGE will offer a theroretical rate of up to 384 Kbs. •Beyond EDGE, 3G (UMTS) cellular systems will eventually offer data rates up to 2 Mbs N+I_2k © 2000, Peter Tomsu 01_mobile_wirel 16 Universal Mobile Telephone Service UMTS • 3G mobile system • Developed within ITU-2000 framework • Frequency bands Terrestrial: 1885 – 2025 MHz and 2110 – 2200 MHz Sattelite: 1980 – 2010 MHz and 2170 – 2200 MHz • Data rates up to 2Mbps • Inherent IP support • Fully packet switched (data and voice) • Concept of VME (Virtual Home Environment) N+I_2k © 2000, Peter Tomsu 01_mobile_wirel 17 GSM Cellular Packet Data SSS … Switching Subsystem VLR … Visitor Location Register HLR … Home Location Register AUC … Authentication Center EIR … Equipment Identity Center MSC … Mobile Switching Center BSS … Base Station Subsystem BSC … Base Station Controller BTS … Base Transceiver Stations BTS BSS GPRS SGSN and GGSN provide packet data services VLR SSS HLR AUC Backhaul EIR Internet BSC MSC BTS MSC BSC N+I_2k © 2000, Peter Tomsu Transit Net 01_mobile_wirel GGSN Transit Net SGSN GSN … GPRS Support Node SGSN … Serving GSN GGSN … Gateway GSN 18 GSM Network Areas N+I_2k © 2000, Peter Tomsu 01_mobile_wirel 19 GSM Network Areas • GSM network consists of geographical areas Location Areas – LA made up of a group of cells served by a BSC BSC hndles inter cell signaling updates Keeps track of the cell a user is located MSC/VLR Service Areas MSC administers several BSCs handles signaling traffic of inter LA updates Public Land Mobile Networks – PLMNs N+I_2k © 2000, Peter Tomsu 01_mobile_wirel 20 GPRS Logical Architecture SMS-GMSC SMS-IWMSC SM-SC E C Gd MSC/VLR HLR D Gs A Gr Gb TE MT R BSS Um SGSN Gn SGSN Gc Gi PDN GGSN Gn Gp TE Gf EIR GGSN Other PLMN Signalling Interface Signalling and Data Transfer Interface • PS GPRS uses completely different network architecture as underlying GSM network • Thus introduction of two new network nodes GPRS Support Nodes SGSN … Serving GSN (GPRS Support Node) GGSN … Gateway GSN (GPRS Support Node) N+I_2k © 2000, Peter Tomsu 01_mobile_wirel 21 SGSN and GGSN Functionality SMS-GMSC SMS-IWMSC SM-SC E C Gd MSC/VLR HLR D Gs A Gr Gb TE MT R BSS Um SGSN • SGSN Gn SGSN Gc Gi PDN GGSN Gn Gp TE Gf EIR GGSN Other PLMN Signalling Interface Signalling and Data Transfer Interface Keeps track of user’s location Performs security functions and access control • GGSN Provides internetworking functions with external networks Simply a strong router with IP and X.25 capability N+I_2k © 2000, Peter Tomsu 01_mobile_wirel 22 Further Elements and Enhancements SMS-GMSC SMS-IWMSC SM-SC E C Gd MSC/VLR HLR D Gs A Gr Gb TE MT R BSS Um SGSN Gn SGSN Gc Gi PDN GGSN Gn Gp TE Gf EIR GGSN Other PLMN Signalling Interface Signalling and Data Transfer Interface • SGSNs are connected to PCUs (Packet Control Units which are part of the BSC) Via Gb interface – with FR links • GSNs are interconnected over Gn interface via IP backbone GPRS backbone or GPRS network • HLR is enhanced with GPRS subscriber information • SMS components are upgraded to support SMS transmission via SGSN N+I_2k © 2000, Peter Tomsu 01_mobile_wirel 23 Intra and Inter PLMN Backbone Networks • Gp interface Packet Data Network Inter-PLMN Backbone Gi Gp GGSN BG Intra-PLMN Backbone SGSN SGSN PLMN A N+I_2k © 2000, Peter Tomsu Gi BG Connects two independent GPRS networks for message exchange GGSN Intra-PLMN Backbone Message exchange done by BG (router) • Gi interface SGSN PLMN B Connection between operator’s GPRS networks and external networks (Internet) 01_mobile_wirel 24 GPRS Support Nodes • GSN is main element in GPRS infrastructure Mobility router Provides connection Enables interworking with various data networks N+I_2k © 2000, Peter Tomsu 01_mobile_wirel 25 GGSN • Used to access external data network • IP router containing all necessary routing info for attached GPRS users • Routing info used to tunnel PDUs to MS’s current point of attachement (SGSN) • Allocation of dynamic IP addresses Either itself or external DHCP server N+I_2k © 2000, Peter Tomsu 01_mobile_wirel 26 SGSN • Serves MS in terms of packet data services • SGSN establishes connection via GGSN to requested data network • Maintains all data structures (contexts) for Authentication Routing process • In case of roaming (SGSN and GGSN in different PLMNs) – interconnected via Gp interface N+I_2k Provides security and others © 2000, Peter Tomsu 01_mobile_wirel 27 PCU • Located in the BSC • Acts as an interface to the SGSN • Distinguishes data and voice • Sends data over FR via SGSN into GPRS backbone • Realized in SW or HW N+I_2k © 2000, Peter Tomsu 01_mobile_wirel 28 APN • Access Point Name • Defined by ETSI in order to deal with huge number of IP networks to connect to • Uniquely identifies the network a user wants to access • L3 protocols defined are IPv4 and IPv6 N+I_2k © 2000, Peter Tomsu 01_mobile_wirel 29 APN N+I_2k Access Point Name (username) Type (Ipv4, Ipv6, X.25) Access mode (non/transparent) DHCP local pool information Accept network initiate PDP create request List of PDP contexts on the APN IP for DHCP, RADIUS … IP for charging gateway © 2000, Peter Tomsu • Contains Name of foreign NW Network access mode • Stored in HLR • User may select APN by himself from the MS 01_mobile_wirel 30 GPRS Concepts • APN: targeted network (ISP, intranet) • PDP context: session id • 1) reach the SGSN (telecom part) • 2) reach the GGSN serving the APN (GTP=moving tunnel) • 3) reach the APN (dedicated link, tunnel) N+I_2k © 2000, Peter Tomsu 01_mobile_wirel 31 GPRS PDN Interworking Model GGSN IP GPRS Bearer Gi IP L2 L1 • GGSN is access point for internetworking Seen from outside as normal router GPRS network seems to be normal IP subnet N+I_2k © 2000, Peter Tomsu 01_mobile_wirel 32 GPRS Transmission Plane Application IP / X.25 IP / X.25 Relay SNDCP SNDCP GTP GTP LLC LLC UDP / TCP UDP / TCP IP IP L2 L2 L1 L1 Relay RLC RLC MAC MAC GSM RF MS Um BSSGP BSSGP Network Service GSM RF L1bis Network Service L1bis BSS Um … radio interface Uses same PL coding as classical GSM Thus no HW changes TE requires up to 8 slots / TDMA frame N+I_2k © 2000, Peter Tomsu Gb SGSN Gn GGSN Gi GTP … GPRS Tunneling Protocol SNDCP … Subnetwork Dependent Convergence Protocol BSSGP … Base Station System GPRS Protocol 01_mobile_wirel 33 Gb Interface Application IP / X.25 IP / X.25 Relay SNDCP LLC SNDCP GTP GTP LLC UDP / TCP UDP / TCP IP IP L2 L2 Relay RLC RLC MAC MAC GSM RF MS Um BSSGP BSSGP Network Service GSM RF L1bis Network Service L1bis BSS Gb SGSN L1 L1 Gn GGSN Gi • Link layer is FR • BSSGP (BSS GPRS) conveys routing and QoS info between BSS and SGSN • SNDCP encapsulates IP traffic between terminal and SGSN Multiplexing of L3 connections Ciphering, segmentation, compression N+I_2k © 2000, Peter Tomsu 01_mobile_wirel 34 Gn Interface Application IP / X.25 IP / X.25 Relay SNDCP LLC SNDCP GTP GTP LLC UDP / TCP UDP / TCP IP IP L2 L2 Relay RLC RLC MAC MAC GSM RF MS Um BSSGP BSSGP Network Service GSM RF L1bis Network Service L1bis BSS Gb SGSN L1 L1 Gn GGSN Gi • GTP (ETSI) tunnels IP packets between SGSN and GGSN One tunnel per active TE • Runs either over UDP or TCP Port #3386 IP N+I_2k © 2000, Peter Tomsu UDP GTP DATA 01_mobile_wirel 35 MS R reference point TE MT Um Gi reference point GPRS network 1 MS PDNs or other networks Gp GPRS network 2 • MS could be Only GPRS phone User with NW connection via GPRS to his PC N+I_2k © 2000, Peter Tomsu 01_mobile_wirel 36 Transparent Internet Access The GGSN is effectively a router The GPRS network appears to the PDN as another IP subnet • User who wants to get connected to internet • MS is given an IP address out of the operators address space Could be statically or dynamically allocated May be public or private • Authentication performed by SGSN via HLR N+I_2k © 2000, Peter Tomsu 01_mobile_wirel 37 Transparent Internet Access N+I_2k © 2000, Peter Tomsu 01_mobile_wirel 38 Non Transparent Access • Allows user to select SPs of his choice • Connection to intranet VPN for email access, intraweb, databases • Has to request IP address and perform authentication in company network • Realized by SGSN during PDP context activation via selected APN • MS sends authentication request • GGSN requests authentication and IP address from specified server (Radius, DHCP) of customers intranet • Use of Ipsec and/or L2 tunnel for terminating private IP addresses at GGSN via Internet N+I_2k © 2000, Peter Tomsu 01_mobile_wirel 39 Interworking Between GPRS Roaming User’s BGP (RFC 1771) N+I_2k © 2000, Peter Tomsu 01_mobile_wirel 40 QoS on GPRS BTS BSC H.323 client FR FR CoS SGSN IP QoS Priotities CAR IP QoS WFQ CRTP CRTP N+I_2k © 2000, Peter Tomsu Transit Net GGSN IP QoS IP H.323 GW PSTN H.323 Gateway WFQ WRED 01_mobile_wirel IP QoS 41 Quality of Service Mapping between GPRS QoS and IP QoS levels Delay Class Precedence Mean-Throughput Resulting “canonical” QoS Class Best Effort any any Best Effort 1, 2, 3 low any Best Effort 1,2, 3 any Best Effort Best Effort 1,2, 3 normal specified Normal 1,2,3 high specified Premium • Use of IP CoS mechanisms in GGSN/SGSN and in the Backbone: WRED, WFQ, CAR • Admission Control (GGSN): S traffic < Total BW N+I_2k © 2000, Peter Tomsu 01_mobile_wirel 42 Backbone Issues • Leverage End-to-End Consistency • WFQ, WRED, CAR • MPLS (GGSN as edge router) • Integrated management N+I_2k © 2000, Peter Tomsu 01_mobile_wirel 43 IP Address Management • GGSN can hold (local pool/DHCP): – Operator’s public IP addresses – Operator’s private IP addresses (NAT) – Other’s public IP addresses (local pool) – Other’s private IP addresses (local pool, dedicated I/F) • configuration per APN N+I_2k © 2000, Peter Tomsu 01_mobile_wirel 44 IP Address Management • GGSN can allocate addresses: – transparently (local pool using built-in DHCP server/DHCP) – non-transparently (CHAP/IPCP processing, RADIUS/DHCP requests generation) through IOS built-in RADIUS/DHCP clients • configuration per APN N+I_2k © 2000, Peter Tomsu 01_mobile_wirel 45 GSM to UMTS Evolution N+I_2k © 2000, Peter Tomsu 01_mobile_wirel 46 Evolution Towards UMTS • UMTS Backward compatibility to legacy systems • Operators will try to use existing infrastructure as long as possible • Development steps 1) MIP on top of GPRS 2) optimize existing routing mechanisms 3) SGSN and GGSN combined in one node • In future UMTS will completely integrate PSTN VSCs will replace all class 4 and class 5 switches Calls will be routed over IP backbone N+I_2k © 2000, Peter Tomsu 01_mobile_wirel 47 Questions ???
