2G Topology

Project Topology
GSM, GPRS and SS7 MAP
2G Interfaces v1.2 (8th April, 2018)
Celebrating 45 years of 1st mobile phone call
Pedro Vieira (neobr88@gmail.com)

To Master Jesus Christ, for not letting me fall.

Organizations/Associations
3GPP (3rd Generation Partnership Project)
3GPP2 (3rd Generation Partnership Project 2)
ITU (International Telecommunication Union)
ITU-T (ITU Telecommunication Standardization Sector)
IMT-2000 (International Mobile Telecommunications - 2000)
CEPT (European Conference of Postal and Telecommunications Administrations), EU
CCITT (Consultative Committee for International Telephony and Telegraphy)
TIA (Telecommunications Industry Association)
ANSI (American National Standards Institute), USA
RFC (IETF Request for Comments)
IETF (Internet Engineering Task Force)
IEEE (Institute of Electrical and Electronics Engineers)
ETSI (European Telecommunications Standards Institute)
ETS (European Telecommunication Standard)
IEC (International Electrotechnical Commission)
OFC (Optical Fibre Communication conference & exposition)
FCC (USA Federal Communications Commission)
EU Council (Council of the European Union) – 1991 for E112
USD (Universal Service Directive) - 2002, article 26 for E112
OMA (Open Mobile Alliance - WAP Forum)
RSOE EDIS (Hungarian National Association of Radio Distress-Signaling and
Infocommunications Emergency and Disaster Information Service)
UN (United Nations)
ECom (Europepean Commision)
GDACS (Global Disaster Alert and Cooordination System) – UN, USA, Ecom
SADN (Serviço de Alerta de Desastres Naturais/PT-BR) – Brasil, March 2018
GSM Arena (https://www.gsmarena.com)

Connectors Technology
BNC (Bayonet Neill-Concelman) – 50/75 Ohm, <4GHz, <500V
RJ-Nx(Registered Jack-11/21/25/45s/48/61)
STP (Shield Twisted Pair)
UTP (Unshield Twisted Pair)
CAT-Nx (Category 1/2/3/4/5/6(e))
4P4C (4 Posistion 4 Contact)
6P2C (6 Posistion 2 Contact)/6P4C (6 Posistion 4 Contact)/ 6P6C (6 Posistion 6 Contact)
8P8C (8 Posistion 8 Contact)/10P10C (10 Posistion 10 Contact)
10BASE2 (Cheapernet, Thinnet, Thin Ethernet, Thinwire) – BNC Connected
GBIC (GigaBit Ethernet Connector) – usually SC connector.
Applications: GigaBit Ethernet, Fiber Channel, Fast Ethernet BiDi GBIC, CWDM/DWDM GBIC
Ethernet =IEEE802.3-10Mbps(10Base)/100Mbps(100Base)/1000Mbps(1000Base)/10Gbps (10GBase)
BiDi (Bi-Direcional WDM) = Full-Duplex, 2 wavelenghts in same fiber 1310/1550 or vice-versa)
CWDM (Coarse Wavelenght Division Multiplexing) = 4/8/16/18 wavelenghts/fiber, ITU-TG.694.2
Band:O(1260-1360)/E(1370-1450,G.652D)/S(1460-1530)/C(1530-1565)/L(1565-1625)20nm/channel
Add-Drop Filter: Passive filter to select channel. Can add the same channel to make redundancy
DWDM (Dense Wavelenght Division Multiplexing)-mult.wavelengths/fiber, pre/pos/ILA opt. Amps
ILA (In-Line Amplifier) – Optical signal regenerator, pre amp – receptor,pos amp – emissor
SOA(Semiconductor OptAmp) - Amps All Pol. States, SM/PM 1.5m opt pigtail FC/APC , 1550nm C band
BOA(Booster OptAmp) - Amps Only One Pol. State, SM/PM 1.5m opt pigtail FC/APC , 1550nm C band
SM (Single Mode Fiber)/PM (Single Mode Polarization-Maintaining)/Opt(Optical)
SFP (Small Form-factor Pluggable) / SFP+ Transceiver - GBIC with small form
XFC (10G optical SFP/XFI) - Serial Optical data using 1270/1330nm transmitter<->receiver
Flat Polishing - 90º Straight Polishing
PC (Physical Contact Polishing) - Rounded Polishing
SPC (Super Physical Contact Polishing) - Rounded Polishing, Quality+
UPC (Ultra Physical Contact Polishing) - Rounded Polishing, Quality++
APC (Angled Physical Contact Polishing) - Angled Polishing, low loss<0.2Db
LC (Lucent Connector) – Single Mode, gaining maket share, 10G Ethernet Transceivers
ST (Straight Tip) - Multi-mode, older-1990, a little > LC
SC (Standard Connector )- Single /Multi-mode, Gigabit Eth, 2RJ-45 aligned in size, 2x > LC
MR-RJ ( Mechanical Transfer Registered Jack ) – Multi-mode, Squared, 2 fibers in 1 connector
FC (Ferrule Core Connector)- was widely used, common for HD Video over Fiber TX Equipment
Splicing - Fiber union by fusion (eletric arc) or mechanical junction (less effective)

Transmission Technology
TX (Transmission)/RX (Reception)
DS (Downstream)/US (Upstream)
UL (Uplnk)/LD (Downlink)
CSD (Circuit Switch Data) – 9.6 kbit/s per TS- in HSCSD, MS will be assigned more than one TS
HSCSD (High Speed Circuit Switched Data)-14.4Kbit/s per slot (57.6Kbit,4 slots/118Kbit, 8 slots)
DTX (Discontinous Transmission) – UL/DL function. reduce interference and save telephone batt
T-carrier (TDM multiplexing over 4-wired TX circuit)
T1 (Transmission System 1, Max 1.544 Mbit/s)
T2 (Transmission System 1, Max 6.312 Mbit/s, with 96 Channels)
T3 (Transmission System 1, Max 44.736 Mbit/s, with 672 Channels)
E1 (CEPT E-carrier, 2 Mbits/s)
E2 (CEPT E-carrier, 8 Mbits/s, 212 bits/row, ITU-T Rec. G.742)
CRC-N (Cyclic Redundant Check-4/8/16/32/64/128bits)
FAS (Frame Alligned System)/ BER (Bit Error Rate)
PDH (Plesiochronous Digital Hierarchy)/SDH (Syncronous Digital Hierarchy)
CCS (Common Channel Signaling)/CAS (Channel Associated Signaling)
LOS (Loss Of Signal)/ OOF (Out of Frame)
AIS (Alarm Indication Signal) – Remote equip LOS, sends ‘all ones’ infinte-loop to inform
RTS/CTS (Request to Send/Clear to Send)
DIP (Digital Path) A/B/C/... function used for supervision of connected PCM lines (2M E1/1.5M T1)
LAG(Link Aggregation Group/Ethernet Bonding) – Surpass port speed restriction/add redundancy
LACP (Link Aggregation Control Protocol) – LAP works in layers 1/2/3 (Physical/Link/ Network)
Single Mode Fiber Opt Cable – less attenuation, long distancies, 9/125 microns core/cladding ratio
Multimode Fiber Opt Cable – more attenuation, short distancies, 50/125 or 62.5/125 microns ratio
Transmission Windows–ITU-T opt wavelenghts bands O-E-S-C-L-U/XL 1260-1675nm
O (Original Band) - 1260-1360nm/E (Water Peak Band,ITU-T G652.D/IEC B1.3) - 1360-1460nm
S (usable) - 1460-1530nm/C (higher-performance systems) - 1530-1565nm
L (higher-performance systems) - 1565-1625nm/U/XL (not used/avoided) - 1625-1675nm
FFTH/FTTS(Fiber To The Home/Subscriber)-MW(MicroWave) Radio, Air Medium x Fiber
GPON(OLT(central)-ONU(subscriber)):Max20Km/60Km(with gain)-FTTS Core/MAN/LAN

Modulation/Multiplexing/Optical Fiber
MSK (Minium Shift Keying)
FSK (Frequency Shift Keying)
0,3GMSK (Gaussian Minium Shift Keying with 0.3-band Gaussian Filter)
GMSK (Gaussian Minium Shift Keying)
PSK (Phase Shift Keying)
8PSK (8-Phase Shift Keying)
PCM (Pulse Code Modulation)
AMC (Adaptative Modulation and Coding)
AMC – HR (Adaptative Modulation and Coding – Half Rate)
AMC – FR (Adaptative Modulation and Coding – Full Rate)
ADM/PCM (Adaptative Differencial Modulation/PCM) – G.721/726
TDM (Time Division Multiplexing)
TDMA (Time Division Multiple Access)
FDMA (Frequency Division Multiple Access)
CDMA (Code Division Multiple Access)
WCDMA (Wideband Code Division Multiple Access)
GPON (GigaBit Passive Optical Network)–1Gb, G.984.1-5, OLT-ONU no energy conn, no risks
OLT (Optical Line Terminal ) /ONU (Optical Network Unit)
SDH/SONET (Synchronous Optical Network)–10Gb Optical Network link, MUX opt links
Stimulated Raman Scattering (LH/ULH Opt Links) – 1928/Chandrasekhara Venkata Raman
WPA (Water Peak Amplification) – Attenuation by glass core hydroxyl (OH)‾ ions, E,U/XL bands
Back Haul/Long Haul(300-800Km)/Ultra Long Haul (>800Km) TX Links
LRA/DRA (Lumped/Distributed Raman Amplification) – No WPA (+12%reach, +27% service area)
RFA/RA (Raman Fiber Amplifiers/Raman Amplifiers)
EDFA (Erbium Doped Fiber Amplifiers)/ASE(Amplified Spontaneous Emition)-population inversion
Pumping Lasers(300-2000nm)-high power active opt gain, 100nm lower of band center frequency
Single Laser Pumping/ Double Laser Pumping/Triple Laser Pumping
Counter-Directional (receptor-sided)/ Co-Directional (emissor-sided)/ Combined - Laser Pumping
OSNR(Optical Signal-Noise Ratio)-related to coupling/attenuation on fiber cable
Chromatic Dispersion – Caused due to refration, phase velocity depends on frequency of LASER
LASER (Light Amplification by Stimulated Emission of Radiation)-1905/Albert Einstein
NLE (Non-Linear Effect) -Effect not mathematically described as polynomial function f(x)=ax+b
FWM (Four Wave Mixing) - phase-sensitive NLE, 2/ 3 wavelengths produce 2/ 1 new wavelengths
XPM (Cross Phase Modulation) – wavelenght’s opt power alters other phase through Kerr Eff., NLE
Kerr/QEO(QuadraticElectro-Optic)Effect- material refractive index change by applied electric field
SPM (Self Phase Modulation)-10ps pulse induces Kerr Eff.,->pulse phase shift->frequency spectrum change

Protocols/ Acronims/ Radio Frequency
QoS (Quality of Service)
PDU (Protocol Data Unit)
PIN (Personal Identification Number)
WAP (Wireless Application Protocol) – 1999
MAC/RLC (Medium Access Control/Radio Link Control)
TCP/IP (Transmission Control Protocol/Internet Protocol)
ARFCN (Absolute Rádio Frequency Channel Number)/MAIO – Mobile Allocation Index Offset
FH (Frequency Hopping)/HSN (Hopping Sequence Number)
P-GSM (Primary GSM, GSM-P) - UL 890-915MHz MS-BTS, DL 935-960MHz (Eu), 124ARCFN
E-GSM (Extended GSM, GSM-E) - UL 880-890MHz MS-BTS, DL 925-935MHz (Eu), 50ARCFN
R-GSM (Railway GSM, GSM-R)-UL 876-880MHz, DL 921-925MHz (Eu), 19ARCFN, <500Km/h
GSM 900 (Eu) - UL 880-915MHz MS-BTS, DL 925-960MHz BTS-MS, 45MHzFH TX-RX
DCS 1800 (Eu) - 1710-1785MHz MS-BTS, 1805-1880MHz BTS-MS, 95MHzFH TX-RX
PCS 1900 (USA)- 1850-1910MHz MS-BTS, 1930-1990MHz BTS-MS, 80MHzFH TX-RX
RF (Radio Frequency) – 124 channels GSM 900 (124 ARFCN), 373 channels DCS 1800
DCS (Digital Cellular System) – GSM 1800
PCS (Personal Communications Service)-1990MHz band CAN/USA/MEX,IMT-2000 (3G)
X.25(CCITT->ITU-T,1976) - standart protocol suite for packet-switched WAN
WAN (Wide Area Network) – Continental-wide network
MAN (Metropolitan Area Network) – City-wide network
LAN (Local Area Network) – Home/Office-wide network
AOMN (All Optical Metropolitan Network) – Optical City-wide network
DS-1 (Digital Signal-1)/ TS(N) (Timeslot(0-31))
DSS1 (Digital Subscriber Signalling System No. 1)-ITU-T I.411(ETS 300 102),4 Codesets/Codeset0=Q.931
CIC (Circuit Identification Code)-NE Codes for ITX, included in ISUP msg
ITX (Interconnection) – Links between MSCs and fixed networks
MO (Mobile Originated)/MT (Mobile Terminated) /PC (Point Code)
LAC (Local Area Code for paging) /LA(Locaion Area)/RA(Routing Area)
BSIC (Base Station transceiver Identity Code)
PCRF (Policy Control and Charging Rules Function)/PCC (Policy and Charging Control)
PCEF (Policy Control Enforcement Function)/ GPS(Global Positioning System)
E112(emergency telephone number)-CEPT 1972/EU Council/USD,charge-free 190/911,LCS-assisted
TLLI(Temporary Logical Link Identifier),UE-SGSNcomm(GSM/GPRS)signaling address3GPP23.003

Signaling Protocols/Tech Acronims
SS7 (Signaling System #7)
MAP (Mobile Application Part) – Roaming
TCAP (Transaction Capabilies Application Part) - Q.771-Q.775 or ANSI T1.114
INAP CS-1(Intelligent Network Application Protocol, Capabilty Set 1)
SCCP (MTP Signalling Connection Control Part)
MTP 1(Message Transfer Part) – ITU-T Q.701/Q.702/Q.703/Q.704/Q.705
MTP2 (Message Transfer Part 2) – ITU-T Q.755/Q.755.1/Q.780/Q.781
MTP3 (Message Transfer Part 3) – ITU-T Q.755/Q.755.1/Q.780/Q.782
CAP (CAMEL Application Part)/ BCSM (Basic Call State Model)
CAMEL (Customized Applications for Mobile networks Enhanced Logic)
ROSE (Remote Operations Service Element protocol)
gsmSCF (GSM Service Control Function)
gsmSSF (GSM Service Switching Function)
gsmSRF (GSM Specialized Resource Function)
gsmSSF (GPRS Service Switching Function)
USSD (Unstructured Supplementary Service Data)
SIGTRAN (extension of the SS7 protocol family, over IP SCTP)
SCTP (Stream Control Transmission Protocol)
UP (SS7 User Part)/ISP(Intermediate Service Part)/TUP (Telephone User Part)
ISUP (ISDN User Part) – Interconnection calls between MSCs and fixed networks
Erlang (Admensional unity of core traffic measure)
CS (Circuit-Switched)/PS (Packet-Switched)/PSE (Packet Switch Exchange)
Conn (Connection)/ Comm (Communication)/P2P(Peer-to-Peer)/VC(Virtual Connection)
Prot (Protocol)/ Auth(Authentication)/ Loc(Location)/ Ctrl(Control)/Subscr(Subscriber)
LBS/LCS (Location Based Services/Location Services) – The same as standardized by 3GPP
User-Plane Location Protocol for A-GPS(Assisted GPS): SUPL (Secure User Plane Location)
Control-Plane Location Protocols (MS-SMLC 3GPP):
RRLP (Radio Resource Location services Protocol),for GSM networrks/TIA 801(cdma2000)
RRC (RRC Position Protocol) for UMTS networks/LPP (LTE positioning protocol) for LTE
VAS (Value Added Services, Media & Content)
M2M (Machine to Machine)/IoT (Internet of Things)
Tunneling – Repacks (encapsulates) protocol as traffic data into a different protocol form
MPLS (Multiprotocol Label Switching) - Directs data from one PS-network node to the next based on
labels. MPLS supports multiple access technologies, including T1/E1, ATM, Frame Relay, and DSL. Eliminate
the need for multiple layer-2 networks(ATM/SONET/FrameRelay/Ethernet) to satisfy different types of traffic
Clustering – Network nodes working together to improve group availability/response/performance

Protocol Layers
MTP Level 1 (SS7 MTP Part) - OSI Layer 1, SS7 Layer 1
SCCP (SS7 User Part) - OSI Layer 3, SS7 Layer 4
ISP (SS7 User Part) - OSI Layer 4-5-6, SS7 Layer 4
TCAP (SS7 User Part) - OSI Layer 7, SS7 Layer 4
MAP (Signaling, Roaming) - OSI Layer 7, SS7 Layer 4
TUP (SS7 User Part) - OSI Layer 3-4-5-6-7, SS7 Layer 3-4
ISUP (SS7 User Part) - OSI Layer 4-5-6-7, SS7 Layer 4
MSC connects Fixed Networks over TUP (SS7 User Part) or ISUP (SS7 User Part)
LAPD (Link Access Protocol on D-channel) - layer 2 protocol on BTS-BSC interface, ISDN
layer 2 protocol, DSS1 layer 2 in ITU-T Q.921, DSS1 layer 3 msgs in ITU-T Q.321)
LAPDm (LAPD mod.ver) - signaling msgs, !frame format/size, layer 2 on BTS-MS interface
B-channel (bearer channel) - voice/data 64 kbit/s channel
D-channel (delta channel) - Control channel in BRI/PRI, TS16 in T1/TS24 in E1(PRI)
H-channel (high-speed comm channel) - H0=384 kbit/s(6 B-channels), H12=30B channels
BRI (Basic Rate Interface) – ISDN Basic Rate Access ,2B+D/2B1D, B=64kbps, D=16kbps
PRI (Primary Rate Interface) – ISDN DS0 =E0 = T0 voice/data TX, B=64kbps, D=64kbps
T1 (PRI T-carrier)-23 B-channels + 1 D-channel for control = 24x64kbit/s = 1.544 Mbit/s
E1 (PRI E-carrier)-30 B-channels + 2 D-channels for control = 32x64 Kbit/s = 2.048 Mbit/s
RSs layer (Radio Subsystem layer) – Abis Physical Layer
RIL3 (Radio Interface Layer 3)
RIL3-RRM(Radio Resource Mgmt)-MS-BSC link, paging/handover/ciphering/radio acss.
RIL3-MM (Mobility Management) - Direct MS-MSC link/roaming, authentication
RIL3-CM (Connection Management) - Direct MS-MSC link/call stabilishment/rel.
BTS MP (BTS Management Protocol) – start ciphering/ able to do paging to localize MS
BSSAP (BSS Application Part) - Radio resources admin/ctrl, maintenance/handover ctrl
DTAP (Direct Transfer Application Part) – MSC-MS link
DTAP-MM (Direct Transfer Application Part – Mobility Management)
DTAP-CM (Direct Transfer Application Part – Connection Management)

Network Technology
AMPS (Advanced Mobile Phone System), 1st Gen – Analog, Bell Labs, October 13, 1983
D-AMPS (Digital-Advanced Mobile Phone System)
GSM (Global System for Mobile Communications)
GSM-EFR (GSM – Enhanced Full Rate), GSM06.60
GPRS (General Packet Radio Service)
GPRS CS (Coding Scheme)
SMS (Simple Message Service)
EDGE (Enhanced Data Rates for Global Evolution)
EDGE MCS (EDGE Modulation and Coding Scheme)
EDGE - IMT-SC ( IMT-2000 - Single Carrier)
E-EDGE - Evolved EDGE (not commercial): 1 Mbit/s DS, 400 Kbit/s US
CDMA2000 – C2K - IMT-MC ( IMT-Multi-Carrier) – IS-2000
TFO (Tandem Free Operation)
CDMA2000 1xRTT (Voice over CDMA2000)
CDMA2000 1xEV-DO (Data over CDMA2000)
EV-DO (Evolution-Data Optimized): Release 0 (Rel. 0)Revision A, Revision B
UMB (Ultra Mobile Broadband) - EV-DO TIA-856 Revision C
IS-95 (Interim Stardard 95, cdmaOne)
NGN (Next Generation Network)
IMSI (International Mobile Subscriber Identity )= MCC-MNC-MIN – ID for msg/signaling
MCC (Mobile Country Code) – IMSI 3 first algarisms, USA 310
MNC (Mobile Network Code) – Next IMSI 2/3 first algarisms AT&T 410
MSIN/MIN (Mobile Subscription Identification Number / Mobile Identification Number) = MSID/IMSI_S
MSID/IMSI_S(Mobile Station ID/Short IMSI)=34bits, 1stgen=call route/2ndgen=temporary number(security)
MIN=MIN1(24LSB)+MIN2(10MSB)-derives from 10-digit number ESN ID(IS-95)=MAX 2^(24)MINs
LSB (Least Significant Bits) / MSB (Most Significant Bits), MSID=rest of IMSI digits, excepting MCC/MNC
ESN (Electronic Serial Number)-FCC-created to uniquely identify mobile devices, starts in early 1980, CDMA
MNO(Mobile Network Operator)-used RF1982 Serial Number Arithmetic duo to limited bits (10) for ESN ID
MVNO/VNO (Mobile Virtual Network Operator/ Virtual Network Operator)
MDN(Mobile Directory Number ) – In CDMA world, is the device's telephone number
MS ID (Mobile Station Idtification) =SIM(ICCID)+ME (IMEI)
ICCID ( Integrated Circuit Card ID) –19/20 bits SIM chip identifier, can’t be altered, international
IMEI (International Mobile Equipment Identity)-stored in EIR (validation), can’t be altered, *#06#code
MSISDN (Mobile Station ISDN number)-full subscriber phone number (allow device to be called)
IMSI=64-bit field unique ID for all mobile networks,MCC/MNCtuple=triplets(3),IMEI=also in satellite phones

GSM Network Elements
U (User)/UE(User Equipment)/MS (Mobite Station) = ME + SIM
ME (Mobile Equipment) /SIM (Subscriber Identity Module)
BTS (Base Transceiver Station)/RBS (Radio Base Station)
RBS (Radio Base Station)
BSC (Base Station Controller)-Stand alone. For GSM 900/GSM 1800, MAX 1020 TRXs
BSC with TRC - MAX1020 TRX (Transceivers), MAX 15 stand alone BSCs
TRAU/TRC (Transcoder Rate Adapter Unit/Trasncoder Controller)-MAX 16 BSCs
MSC (Mobile-Services Switching Center, Mobile Switching Centre)
Monolithic Mobile Switch NE, No IN, all services lumped
MSC (Mobile-Services Switching Server, Mobile Switching Server)
Mobile Server to All-Distributed Mobile Services for uncharging MSC traffic/ processing
SMSC (Short Message Service Center)
RAN (Radio Access Network)/ Core (Network Kernel)
BSS (Base Station System) NSS (Network Station System)/ CN (Core Network)
VLR (Visitor Location Register) – Roaming
HLR (Home Location Register)/HSS (Home Subscriver Server)
EIR (Equipment Identity Register) – IMEI Register
AuC (Authentication Center) – HLR subscriber ID key, encryption BSC-MS
IN (Intelligent Network)/ SS (Switching System)/Broker (Comm Intermediary)
PSTN (Public Switched Telephone Network)/POTS (Plain Old Telephone Service)
PABX/PBX (Private Bank Exchange)/PLMN (Public Land Mobile Network)
ISDN (Integrated Services Digital Network)
OSS (Operational Support System)/OMC (Operational & Maintenance Center)
NMC (Network Management Center)
MSC-S (Mobile Switching Center Servers)
CG (Charging Gateway)/ CGF (Charging Gateway Function)
OCS (Online Charging System)
RADIUS (Remote Authentication Dial In User Service)
Diameter (doubled RADIUS, auth evolved protocol)

GPRS Network Components
SGSN (Serving GPRS Support Node)
GGSN (Gateway GPRS Support Node)
IMS (IP Multimedia Subsystem/IP Multimedia Core Network Subsystem)
SGW (Serving Gateway)
PGW (PDN Gateway)
PDN (Packet Data Network)
CDF (Charging Data Function)
CGF (Charging Gateway Fucntion)
OFCS (Offline Charging System)
CDR (Charging Data Record)
TCP (Trasnmission Control Protocol)
UDP (User Datagram Protocol)
IP-SM-GW (IP-CAN Short Message Gateway)
IP-CAN (Internet Protocol Connectivity Access Network)
IWMSC (Inter Working Mobile Switching Centre)
PDP (Packet Data Protocol)
CAMEL (Customized Applications for Mobile network Enhanced Logic)
TDP-R (Trigger Detection Point Requests)
EDP-R (Event Detection Point Requests)
EDP-N (Event Detection Point Notifications)
STP (Signaling Transfer Point)
GMLC (Gateway Mobility Location Center) Server
SMLC (Serving Mobile Location Server)
GMSC (Gateway Mobile Switching Centre)
VMSC (visited Mobile Switching Centre)
AAA (Authorization, Authentication and Accounting) server
DHCP (Dynamic Host Control Protocol) Server

A Simple Introduction
In this brief book we will discuss about GSM, also known as second generation of
mobile telecom tecnology or simply, 2G. GSM services are provided with digital
transmission in mind, so that the old analogic 1st gen tecnology and transmission
could be surpassed.
Topology is the core topic of this research. Here we will focus our study in GSM
codification and interfaces, which make the transmission of information possible.
We will also focus on the network elemments and protocols that handle the services
and comm links in GSM network.
The 2nd generation was responsible for the unification of Europe telecom so it
began the basis of all the other generations that came after it. Understanding GSM
centainly is crucial if we were to compreend how 3rd and 4th gens work and how
they intercommunicate.
Figure 1: Interfaces in GSM Topology (by Pedro Vieira in yEd Graph Editor)

Interfaces
Interations between devices are handled by predefined interfaces. Those interfaces
are predefined and thus protocols characteristics are designed to attend to such
requirements.
From here on we will discuss briefly about characteristics of each interface. Let us
categorize the interfaces’ topics as follows:
Interface Name
Description: Brief information
Development/Technology: Development and features
Deployment/Release: Date and deploying companies
Generation (RFC-ID): Technical Identification (RFC/ID)
Network Elements: NEs linked by interface
Capabilities/Services: Data rates and capacity info
Modulation/Multiplexing: Type of modulation used
Throughput : Speed in single transfering
Type : Air, Cable, Optical Fiber
Bandwidth: Spectrum of operation frequency per slots

GSM Interfaces (User and Air Interfaces + CS Links)
Um - U-MS (User – Mobile Station)
Sm - MS-BTS (Mobile Station – Base Transceiver Station)
Abis - BTS-BSC (Base Transceiver Station – Base Station Controller)
Asub/M - BSC-TRAU (Base Station Controller – Transceiver Rate Adapter Unit)
A - TRAU-MSC (Transceiver Rate Adapter Unit – Mobile Switching Centre)
B - MSC-VLR (Mobile Switching Centre – VLR, often internal interface)
C - MSC-HLR (Mobile Switching Centre – Home Location Register)
D/D’ - VLR(MSC)-HLR (Mobile Switching Centre – Home Location Register)
E - MSC-MSC (Mobile Switching Centre – x, inter-MSC handover)
F - MSC-EIR (Mobile Switching Centre – EIR, equipment identity check)
G - VLR-VLR (Visitor Location Register- Visitor Location Register enquiry) - Roaming
H - HLR-AuC (Home Location Register-AuC, often internal interface)
J - HLR-gsmSCF (Home Location Register- GSM Service Control Function)

Sm Interface
 Description:
Simply the way user interacts with the phone i.e. Mobile Station (MS)
 Development/Technology:
(QWERTY) Keypad/Touch Screen/Voice Recognition/Graphene?/Holograph?
 Deployment/Release:
1st Gen:1981/1982 – 2nd Gen:1987 – 3rd Gen: 1998 – 4th Gen: 2008
 Generation (RFC-ID):
1 Gen – AMPS (Analog Transmission)
1.5 Gen – D-AMPS (IS-54, IS-194)
2 Gen (GSM)
2.5-2.9 Gen (GPRS, EDGE)
3 Gen (UMTS)
3.5 Gen (HSPDA,HSUPA)
3.75 Gen (HSDPA+)
4 Gen (LTE)
4.5 Gen (LTE Advanced)
4.75 Gen (LTE Beyond)
5 Gen?
 Network Elements:
U-MS
 Capabilities:
None
 Modulation/Multiplexing:
None
 Throughput :
User-Dependent
 Transmission Type :
Physical
 Bandwidth:
None

Um Interface (Max 30Km)
IS-54: 30KHz in 3 TS, IS-136: SMS, CSD, improved compression protocol
0,3GMSK in 4x(+/-67.708KHz)=270.833 KHz, 4.615 s in 8TS=1 frame
25MHz 124 ARFCN FDMA, 1TS=156.25bits, 576.9 µs, 1bit=3.692 µs
Layers: L1:RSs layer, L2:LAPDm, L3:RIL3-RRM/RIL3-MM/RIL3-CM
1993: TDMA deployed in USA and Canada
2003: Cingular, now AT&T - first commercial use of EDGE in USA
2 Gen – GSM, GPRS, 2.5-2.9 Gen (EGPRS, EDGE)
MS-BTS
 Capabilities:
ADM/PCM (16/24/32 Kbps), AMC-HR (4.75/5.15/5.9/6.7/7.4/7.95 Kbit/s),
AMC-FR (4.75/5.15/5.9/6.7/7.4/7.95/10.2/12.2 Kbit/s), GSM-EFR (12.2 Kbit/s)
GPRS CS (Initial rel.), EDGE MCS, GSM 900/1800/PCS 1900, TX=RX 200Kbit/s data rate
GMSK – modes GPRS CS1-CS2-CS3-CS4, EDGE MCS1-MCS2-MCS3-MCS4
8PSK – 3 times + efficient, modes EDGE MCS5-MCS6-MCS7-MCS8-MCS9
 Throughput :
In GPRS (CS1/CS2/CS3/CS4)
No MAC/RLC (air data/signal TXRX PDU) overhead: 8/12/14.4/20 Kbit/s/slot
With MAC/RLC overhead: 9.2/13.55/15.75/21.55 Kbit/s/slot
In EDGE (MCS1/MCS2/MCS3/MCS4/MCS5/MCS6/MCS7/MCS8/MCS9)
No MAC/RLC overhead: 8/10.4/14.8/16.8/21.6/28.8/44/53.6/58.4 Kbit/s/slot
With MAC/RLC overhead: 9.2/11.6/15.2/18/22.8/30/45.2/54.8/59.6 Kbit/s/slot
Air
 Bandwidth:
Max 256 Kbit/s for 4 TS (packet mode), <150 ms end-to-end latency
Max 473.6 Kbit/s for 8 TS (packet mode), <150 ms end-to-end latency

Abis Interface
ITU-U G.703 (Physical Layer PCM, E0=64 Kbit/s)
T-carrier T-1 (64 kbit/s streams, 8 Kbits/s for framing to sync/demux)
Layers: L1:Physical layer, L2:LAPD, L3:BTS MP
BTS (Base Transceiver Station) = 2G RBS (Radio Base Station)
Transported Over 75 Ohm Coaxial Cable, BNC Terminated
Transported Over 120 Ohm Twisted Pair Cable, RJ48C Terminated
1957: T-carrier developed by AT&T Bell Labs
1962: T-carrier first employed for long-haul PCM digital voice TX with D1
LAPD signaling (E1=10TRU), LAPD MUX(1TRU=2TS,E1=15TRU,2MbpsPCM)
LAPD: 64kbit/s channel+2(4x16=64kbps)channel/TRU(Transceiver Unit, 8TS)
2TRU/cell=traffic:14channels+BCCH/SDCCH:2channels=14x(16kbps)=3.5PCM TS
BTS-BSC
 Capabilities:
PCM24 over T1/PCM30 frame types over E1
T-1 Trunk Max 24 telephone calls w/DS-1/
DS-1 special bits: framing bit/maintenance-signaling bit
T-carrier T-1 (TDM multiplexing, Max 1.544 Mbit/s), FAS, CCS, CAS
BSC-BTS Signaling Exchange, BSC-BTS Sync info, Voice/Data traffic
TDM multiplexing over 4-wired TX circuit (T-carrier)
 Throughput :
Vendor-Specific
Cable
 Bandwidth:
64 Kbit traffic channels with voice/ data or 16 Kbit signalling channels

Asub Interface / M Interface
 Descrption:
(DE)MUX GSM Radio Interface 13/12.2/6.5 Kbit/s - MSC switch 64 Kbit/s
ITU-U G.703 (Physical Layer PCM, E0=64 Kbit/s),
ITU-U G.711 GSM CODEC (64 Kbit/s), Tandem Operation
BSC-TRAU
 Capabilities:
MSC switch PSTN/ISDN 64 Kbit/s voice rate
GSM radio PCM data rate 13(FR)/12.2/6.5(HR) Kbit/s
 Throughput :
64 Kbit/s incoming from Core and 16 Kbit/s incoming from BSS, up to 32TS
Cable
 Bandwidth:

A Interface
G.711 GSM CODEC A-law(World)/U-law(North America and Japan)
T-carrier T-1 (TDM multiplexing, MAX 1.544 Mbit/s), FAS, CCS, CAS
ITU-U G.711 GSM CODEC (64 Kbit/s), Tandem Operation, TFO
SS7 MTP, SCCP, BSSAP, BSSMAP, DTAP-MM, DTAP-CM
BTS- TRAU intern to MSC (TRAU-MSC is often an internal vendor interface)
 Capabilities:
CCITT (2 Mbits/s), PCM24 frame type over T1/PCM30 frame type over E1
T-1 Trunk up to 24 telephone calls with DS-1
DS-1 special bits: framing bit/maintenance-signaling bit
MTP:Routing/transport of signlaing messages, SCCP:conn-less and conn-oriented SCCP
BSSAP:Radio resources admin and control, maintenance control, handover control
DTAP: MSC-MS link, DTAP Mobility Manangement and DTAP Connection Management
 Throughput :
2 Mbits/s (1 E1)
Cable
 Bandwidth:

B Interface
Internal Interface as VLR resides in MSC
--
MSC-VLR
 Capabilities:
--
--
 Throughput :
--
Circuit-Integrated
 Bandwidth:
--

C Interface
MSC-HLR MAP Comm to retrive/store routing info
MSC-HLR TCAP Comm to manage dialog between NEs
HLR comes often with integrated NEBS (Network Element Backup Server)
HLR handle millions of clients and supports features (additional functions)
SMS, Service Center messages between MSC to HLR
Technical realization of the Short Message Service (SMS) – 3GPP TS 23.040
SMS over generic 3GPP Internet Protocol (IP) access – 3GPP TS 23.204
MAP – 3GPP TS 29.002
TCAP – ITU-T Q.773
SCCP – ITU-T Q.711-714
M3UA – RFC 4666
SCTP – RFC 4960
MSC-HLR
 Capabilities(application context (AC) 3 for the following 3GPP Mobile Application services):
Short Message Routing Information Retrieval (AC 2, AC 3)
Short Message Delivery Status Reporting
Inform Service Center
Alert Service Center
--
 Throughput :
--
Cable
 Bandwidth:
--

D/D’ MAP Interface
Subscriber info authentication, update, purge and insert
VLR(MSC)-HLR MAPcomm to transfer, erase and modify subscriber info
M3UA – RFC 4666
SCTP – RFC 4960
WLAN AAA (Wireless Local Area Network, Authorization, Authentication and Accounting)
HLR-VLR(D), HLR-AAA(D’)
 Capabilities (following services):
Authentication Information Retrieval
Authentication Failure Report
Update Location
Cancel Location
Insert Subscriber Data
Restore Data
Purge MS
Ready for SMS
Provide Roaming Number
Reset
--
 Throughput :
--
Cable
 Bandwidth:
--

E MAP Interface
MSC-MSC MAP Protocol for inter-MSC handover
ISUP ITX CIC Conn over E1/T1 trunks divided into 64Kbit/s TS, 1TS=1 call
ISUP can provide status info and circuit management
1980 – ISUP Yellow Book
1984 – ISUP Red Book
1988 – ISUP Blue Book
1991 – ISUP ITU-T Q.767
1992 – ISUP'92 White Book (segmentation, compatibility, new supplementary services)
1997 – ISUP'97 (new procedures, IN CS1, new supplementary services)
ITU-T Q.761 section 2.4.1 : ISUP interworking ISUP'92 is backwards compatible with ISUP
Blue Book (1988) and Q.767 (1991) for basic call procedures and supplementary services
except for some procedures (e.g. number portability)
SS7 MAP – 3GPP TS 29.002
M3UA – RFC 4666
SCTP – RFC 4960
MSC-MSCx, Fixed Networks
 Capabilities (services):
MAP-MT-FORWARD-SHORT-MESSAGE v1/2/3
MAP-MO-FORWARD-SHORT-MESSAGE v1/2/3
--
 Throughput :
--
Cable
 Bandwidth:
--

F Interface
SS7 MAP Protocol to retrieve IMEI from EIR
--
MSC-EIR
 Capabilities:
--
--
 Throughput :
--
Cable
 Bandwidth:
--

G Interface
SS7 MAP Protocol to support subscriber info between VLRs
--
VLR-VLRx
 Capabilities:
Inter-VLR MAP enquiry via Internet
--
 Throughput :
--
Cable
 Bandwidth:
--

H Interface
SS7 MAP Internal Interface as AuC resides in HLR
--
HLR-AuC
 Capabilities:
MAP Protocol to HLR access AuC database
--
 Throughput :
--
Circuit-Integrated
 Bandwidth:
--

J Interface
SS7 MAP Protocol to support GSM Service Control Functions (gsmSCFs)
HLR Mobile Subscriber data repository
HLR authentication information
HLR routing information services
M3UA – RFC 4666
SCTP – RFC 4960
HLR-gsmSCF
 Capabilities( Services from the gsmSCR to the HLR):
MAP-ANY-TIME-INTERROGATION
MAP-ANY-TIME-MODIFICATION
MAP-ANY-TIME-SUBSCRIPTION-INTERROGATION
MAP-SEND-ROUTING-INFORMATION
MAP-UNSTRUCTURED-SS-NOTIFY
MAP-UNSTRUCTURED-SS-REQUEST
--
 Throughput :
--
Cable
 Bandwidth:
--

GPRS Interfaces (PS Links + SS7)
Ga-z – MSC-SGSN (PS interfaces over Ethernet/SS7) + Lg MAP (LCS Tracking)
Ga – CGF, CDF in SGW, PGW, SGSN and GGSN/Generates CDR data/CG-GGSN comm
Gb – BSS-SGSN (GMM/NM signaling and user data)/PFM/mux over NS-VL/VC abstraction
Gc – Reports routing information/reachability for GPRS; Reports PDP context activation
Gd – Message service over PS via IP-SM-GW(IP-CAN)
Ge – GSM/GPRS carrier-grade, value added services (over IN CAMEL, SS7 CAP)
Gf – EIR connection over SS7 for equipment identity check
Gi – GGSN to external PDN (WAP/Internet/Corporative Intranet)
Gn – Control events for a GTP Serving Node (GSN) to comm with internal PLMN (2G/3G)
Gp – Control events for a GTP Serving Node (GSN) to comm with external PLMN (2G/3G)
Gr/Gr’ – HLR Subscriber authentication/profile/location services for SGSNs (HLR/HSS)
Gs – Allows paging and station availability when it performs data transfer. BSSAP+
Gx (optional) – Tandem/ Diameter Charging rules based on IMS session flow
Gy (optional) – Provides Online time- and volume-based DCCA charging data
Gz – Provides Offline (CDR-based) GGSN-CRF charging data
Gxx – BBERF/Tandem Diameter/PCRF-SGW EPC Gxc/PCRF- AGW trusted IP-CAN Gxa
AAA/DHCP–Authorization,authentication,accounting/Provide IP addresses to MS on PDP context
Lg – LCS tracking for using A-GPS/LMU/TDOA/CELLID+RTT/RFPM by GMLC/SMLC
Gg – x
Gh – x
Gj – x
Gk – x
Gl – x
Gm – x
Go – x
Gq – x
Gt – x
Gu – x
Gv – x
Gw – x
Gmb - Control MBMS bearers, GGSN/BM-SC(Broadcast-Multicast Service Center) comm
Blue: Essential Info Black:Additional Info Red: Not described

Ga GTP Prime Interface
Provide charging detail records (CDRs) to the charging gateway (CG, also known as the
Charging Gateway Function (CGF))
Charging Gateway Function/OFCS over PS incapsulated in TCP/UDP
Handles GGSN comm with the Charging Gateway (CG)
CG is responsible for sending GGSN Charging Data Records (G-CDRs) received from the
GGSN for each PDP context to the billing system
GGSN communicates with the CGs on the PLMN using GTP Prime (GTPP/GTP’)
Ga - 3GPP TS 32.240/TS 32.351/ TS 32.295
TCP -RFC 793/ UDP - RFC 768, registered port 3386
GTP Prime (GTP’)/PLMN (Public Land Mobile Network) – 2G/3G
DCCA (Diameter Credit-Control Application)
Session-Based Charging Function (SBCF) – OCS function
Account Balance Management Function (ABMF) – OCS function
Event-Based Charging Function (EBCF) – OCS function (may be not available)
2.5-2.9 Gen (EGPRS, EDGE)
CG-GGSN, OFCS - S-GW, OFCS - P-GW, OFCS - GGSN, OFCS - SGSN
 Capabilities:
Supports charging cenarios and CDR data types
IP-CAN bearer charging data (S-CDR, SGW-CDR, PGW-CDR)
Service data flow charging data (PGW-CDR)/Mobility management charging data (M-CDR)
SMS charging data (S-SMO-CDR, SMS-SMT-CDR)
Location request charging data (LCS-MO-CDR, LCS-MT-CDR, LCS-NI-CDR)
MBMS bearer context charging data (S-MB-CDR, G-MB-CDR)
DWDM (MUX/DEMUX)
 Throughput :
Demand-Driven (in Erlangs)
Internet-Routed Link, Fiber Channel
 Bandwidth:
Gigabit Ethernet (NGN)

Gb (Frame-Relay/IP) Interface
BSS-SGSN (GMM/ NM signaling and user data)/ packet flow management (PFM)
GMM (auth/loc/GPRS attach/detach procedures/paging/GPRS update status/TLLI forming)
Signaling and user data are sent in the same transmission plane
MUX many active users on same physical resource
TX over Point-to-point (PTP) physical lines / Frame Relay / IP network
NS (SNS/NSC divided) layer over Frame Relay protocol
SNS (subnetwork service) - based on frame relay
NSC (network service control) - independent of the transmission network
NS-VL/NS-VC(Network Service Virtual Link/Virtual Connection) abstractions
P2P SNS-NSC comm across the Gb interface bet over virtual connections (1 VC per cell )
BSSGP layer - ensures BSS-SGSN TX of upper-layer LLC PDUs (1-n layer 2 links per VC)
GMM (GPRS Mobility Management)/NM (Network Management)
PFM (Packet Flow Management )/LLC (Logical Link Control protocol)
2.5-2.9 Gen (EGPRS, EDGE) / 3G (UMTS UTRAN Iu)
BSS(MSC)-SGSN
 Capabilities/Services:
NS/ BSSGP layers manage BSS-SGSN virtual conns (verification of the availability of the
virtual connections, initialization, and restoring of a virtual connection)
NS layer provides information on the status and the availability of the virtual connections
to the BSSGP layer. It ensures the distribution of upper-layer PDUs between the different
possible virtual connections (load-sharing function)
SNS provides access to the intermediate transmission network (frame relay network)
NSC is responsible for upper-layer data (BSSGP PDUs) transmission, load sharing, and
virtual connection management
BSSGP layer also ensures the data flow control between the SGSN and the BSS
One-to-one relationship between the BSSGP in the SGSN and in the BSS (if one SGSN
handles several BSSs, the SGSN must have one BSSGP protocol machine for each BSS)
Frame-based, multiplexed link NS layer transport mechanism
 Throughput :
 Bandwidth:

Gc GTP-to-MAP Interface
This interface is used for network initiated PDP contexts (GPRS services for GGSNs)
This is the interface used by the GGSN to communicate with the Home Location Register
(HLR) via a GTP-to-MAP (Mobile Application Part) protocol convertor
For network initiated PDP contexts, GGSN will comm with the protocol convertor using
GTP. The convertor, in turn, will comm with the HLR using MAP over SS7
Request routing information for specified subscribers
Report PDP context activation failures for specified subscribers
The GGSN may be a licensed Cisco product and therefore, separate session and feature
licenses may be required. In case it is developed by vendor Cisco, GGSN should be a StarOS
application that runs on Cisco ASR 5x00 and virtualized platforms. The Cisco GGSN is
available for ST16 and chassis running StarOS™ Release 7.1 or later
One Gc interface can be configured per system context
MAP - 3GPP TS 29.002
M3UA – RFC 4666
SCTP – RFC 4960
GTP/SS7 (GPRS Tunelling Protocol/Signaling System 7)
GTP-to-MAP (Mobile Application Part) protocol convertor
GGSN - HLRs
Retrieval of routing information for GPRS
Reporting failure to establish a network-requested PDP context
Reporting that an MS has become reachable for GPRS
DWDM (MUX/DEMUX)
 Throughput :
 Bandwidth:

Gd SS7,IP Interface
Mobile Originated (MO) and Mobile Terminated (MT) messages in a mobile-to-mobile
scenario over an IP-CAN Short Message Gateway (IP-SM-GW)
M3UA – RFC 4666
SCTP – RFC 4960
SGSN – SMS-C/GMSC/IWMSC – IP-SM-GW
Forward MO Short Message
Forward MT Short Message
Mobile-to-Mobile Short Message
DWDM (MUX/DEMUX)
 Throughput :
 Bandwidth:

Ge CAP Interface (IN conn)
GSM/GPRS carrier-grade, value added services such as unified messaging, prepaid, fraud
control and Freephone
gsmSCF (Service Control Function) features over CAMEL
USSD (Unstructured Supplementary Service Data) via IN
CAP (CAMEL Application Part) signaling by IN, it is a ROSE prot, layered in top of TCAP
ROSE (Remote Operations Service Element
CAMEL Phase 4 – 3GPP TS 23.078 (Customized Applications for Mobile networks Enhanced Logic)
M3UA – RFC 4666
SCTP – RFC 4960
IN (Intelligent Network) SS7 Conn (SCP/SSP,SDP/STP/SEP)
SGSN – gsmSCF – SGSN
CAMEL Trigger Detection Point Requests (TDP-R)
CAMEL Event Detection Point Requests (EDP-R)
CAMEL Event Detection Point Notifications (EDP-N)
CAMEL Session Dialogue (GPRS session and related PDP contexts controlled within a
single GPRS dialogue)
CAMEL PDP Context Dialogue (each PDP context is controlled with a separate GPRS
dialogue)
DWDM (MUX/DEMUX)
 Throughput :
 Bandwidth:

Gf MAP Interface
Equipment Identity Register (EIR) functionality over SS7
M3UA – RFC 4666
SCTP – RFC 4960
SGSN – EIR – SGSN
Mobile Application Check International Mobile Station Equipment Identity (IMEI) service
Handles check requests and attach attempts by subscribers with IMEI (valid and invalid)
DWDM (MUX/DEMUX)
 Throughput :
 Bandwidth:

Gi (IP to external PDN) Interface
Used by the GGSN to communicate with Packet Data Networks(PDNs) external to PLMN
Route data traffic between the subscriber's Mobile Station (MS) and a Packet Data
Networks (PDNs) such as the Internet or an intranet
One or more Gi interfaces can be configured per system context
PDNs are associated with Access Point Names (APNs) configured on the system
Each APN consists of a set of parameters that dictate how subscriber authentication and IP
address assignment is to be handled for that APN
GGSN/FA (GGSN/Foreign Agent)
HA (Home Agent)
GGSN/FA/HA (GGSN/ Foreign Agent /Home Agent)
PDN/APN (Packet Data Networks/Access Point Names)
WAP(Wireless Application Protocol) – WML,WAP 1.2 Push/XML(2.0), ‘Wait and Pay’ JPN
Internet/ Intranet
Proxy
2G GSM/ 2.5-2.9 Gen (EGPRS, EDGE)
GGSN-external PDNs(WAP->Internet/Internet/Corporative Intranets)
Inbound packets received on this interface could initiate a network requestedPDPcontext if
the intended MS is not currently connected
The system can be configured to support Mobile IP and/or Proxy Mobile IP data
applications to provide mobility for subscr IP PDP contexts (GGSN/FA,HA, GGSN/FA/HA)
For systems configured as a GGSN/FA, this interface is used to communicate with HAs for
Mobile IP and Proxy Mobile IP support
For Mobile IP and Proxy Mobile IP, at least one Gi interface must be configured for each
configured FA service
When the system is simultaneously supporting GGSN, FA, and HA services, traffic that
would otherwise be routed over the Gi interface is routed inside the chassis
DWDM (MUX/DEMUX)
 Throughput :
 Bandwidth:

Gn GTP (internal GGSN) Interface
Handles GGSN to comm with SGSNs on the same PLMN (2G GPRS /3G UMTS)
Serves signaling and data path for establishing and maintaining subscriber PDP contexts
Establish and maintain subscriber Internet Protocol (IP) or Point-to-Point Protocol (PPP)
type Packet Data Protocol (PDP) contexts originated by either the mobile or the network
GTP-Cv1 (GPRS Tunneling Protocol Version 1, Control Plane)
GTP-U (User Data Plane over the signaling interface)
GTP interface used between the Serving GPRS Service Node (SGSN)
GPRS Gateway Serving Node (GGSN) over SS7
GTP enables multiprotocol packets to be tunneled through the UMTS/GPRS backbone
between GSNs (2G-2G) and between SGSN and UTRAN (2G/3G-3G)
In the signaling plane, GTP specifies a tunnel control (tunneling) and management
Within the system, a single interface can serve as both a Gn and a Gp interface
One or more Gn/Gp interfaces can be configured per system context
GTPv1-C – 3G99 Ts 29.060 (GTP signaling and control)
GTPv1-U – 3GPP TS 29.281 (GTP user data transfer)
GTP Serving Node (GSN)
RANAP (Radio Access Network Application Part) – 3G (ctrl by RANAP, data over GTP-U)
UDP
IP/Ethernet/ MPLS (Multiprotocol Label Switching)
PLMN (Public Land Mobile Network) – 2G/3G
2.5-2.9 Gen (EGPRS, EDGE) /3G (UMTS UTRAN) – Iu (GTP-U only, RANAP for 3G ctrl)
SGSN-GGSN (internal)
 Capabilities/Services: (control events for a GTP Serving Node):
Create PDP Context Request/Response
Update PDP Context Request/Response
Initiate PDP Activation Request/Response
Delete PDP Context Request/Response
DWDM (MUX/DEMUX)
 Throughput :
 Bandwidth:

Gp GTP (external GGSN) Interface
Handles GGSN to comm with SGSNs on others PLMN (2G GPRS /3G UMTS)
Serves signaling and data path for establishing and maintaining subscriber PDP contexts
Establish and maintain subscriber Internet Protocol (IP) or Point-to-Point Protocol (PPP)
type Packet Data Protocol (PDP) contexts originated by either the mobile or the network
GTP-Cv1 (GPRS Tunneling Protocol Version 1, Control Plane)
GTP-U (User Data Plane over the signaling interface)
GTP interface used between the Serving GPRS Service Node (SGSN)
GPRS Gateway Serving Node (GGSN) over SS7
GTP enables multiprotocol packets to be tunneled through the UMTS/GPRS backbone
between GSNs (2G-2G) and between SGSN and UTRAN (2G/3G-3G)
In the signaling plane, GTP specifies a tunnel control (tunneling) and management
Within the system, a single interface can serve as both a Gn and a Gp interface
One or more Gn/Gp interfaces can be configured per system context
GTPv1-C – 3G99 Ts 29.060 (GTP signaling and control)
GTPv1-U – 3GPP TS 29.281 (GTP user data transfer)
GTP Serving Node (GSN)
RANAP (Radio Access Network Application Part) – 3G (ctrl by RANAP, data over GTP-U)
UDP
IP/Ethernet/ MPLS (Multiprotocol Label Switching)
PLMN (Public Land Mobile Network) – 2G/3G
2.5-2.9 Gen (EGPRS, EDGE) /3G (UMTS UTRAN) – Iu (GTP-U only, RANAP for 3G ctrl)
SGSN-GGSN (external)
 Capabilities/Services (control events for a GTP Serving Node):
Create PDP Context Request/Response
Update PDP Context Request/Response
Initiate PDP Activation Request/Response
Delete PDP Context Request/Response
DWDM (MUX/DEMUX)
 Throughput :
 Bandwidth:

Gr/Gr’ MAP Interface
Subscriber authentication, profile, and location services for SGSNs
HLR/HSS SS7 conn for attaching to the PS network and location update
SGSN’s Gr/WLAN AAA’s Gr’ interface (appearing as an SGSN)
M3UA – RFC 4666
SCTP – RFC 4960
HLR/HSS-SGSN
 Capabilities/Services (3GPP Mobile Application services):
Authentication Information Retrieval
Update Location
Cancel Location
Purge UE
Insert/Delete Subscriber Data
Reset
DWDM (MUX/DEMUX)
 Throughput :
 Bandwidth:

Gs internal SS7 Interface
MSC conn for combined CS+PS signaling over PS
Circuit Switched Fallback in Evolved Packet System – 3GPP TS 23.272
BSSAP+ – 3GPP TS 29.018
M3UA – RFC 4666
SCTP – RFC 4960
VLR(MSC)-SGSN
 Capabilities/Services (BSSAP+ procedures by SGSN-VLR associations):
Paging for non-GPRS Services
Location Update for Non-GPRS Services
Non-GPRS Alert
Explicit IMSI Detach from GPRS Services
Explicit IMSI Detach from Non-GPRS Services
Implicit IMSI Detach from Non-GPRS Services
VLR Failure
SGSN Failure
MS Information
DWDM (MUX/DEMUX)
 Throughput :
 Bandwidth:

Gx (optional) Diameter Interface (license-enabled support)
GGSN-CRF comm provides charging rules based on the dynamic analysis of flows on IMS session
3GPP Diameter Protocol auth/PCC(PCEF)/PCRF/C-SGN/VoLTE 4G(Voice over LTE)
The system provides enhanced support for use of Service Based Local Policy (SBLP) to provision and
control the resources used by the IMS subscriber. It also provides Flow based Charging (FBC)
mechanism to charge the subscriber dynamically based on content usage
PCRF (Policy Control and Charging Rules Function)
PCC (Policy and Charging Control) functionality in PCEF
PCEF (Policy Control Enforcement Function)PCC interactions with Rx/Sd/Ro/Rf/Sy/S9
Tandem Diameter Protocol compliance
Tandem Diameter Routing Agents (DRA)/Proxies/Relay Agents/Redirect Agents
CIoT Serving Gateway Node (C-SGN) with MME, SGW, and PGW functions
Gx – 3GPP TS 23.203 and TS 29.212/Diameter – RFC 6733/ 3588/5516 (RADIUS auth evolved)
SCTP – RFC 4960/ TCP – RFC 793
IMS (IP Multimedia Subsystem), SBLP (Service Based Local Policy), Flow based Charging (FBC)
2.5-2.9 Gen (EGPRS, EDGE) /3G /(UMTS)/4G(LTE)
PGW-PCRF(CRF)-GGSN
 Capabilities/Services (On PGW/GGSN PCEF):
Initiate an initial Credit Control Request (CCR-I) for an idle transaction Initiate a Credit Control
Update Request (CCR-U) for an active transaction
Initiate a Credit Control Terminate Request (CCR-T)for an active transaction
Initiate Event Triggers
Initiate Indication of IP Connectivity Access Network (IP-CAN) Service Establishment
Initiate Indication of IP-CAN Service Modification/ Termination
 Capabilities/Services (On PCRF):
Initiate an Abort Session/ Initiate an Reauthorization Request (RAR)
Initiate a Termination request from an active transaction
Initiate a rule install for an active transaction /Initiate a rule remove for an active transaction
Initiate an Application Detection and Control (ADC) rule install for an active transaction
Initiate an ADC rule remove for an active transaction
Initiate an event to update Quality of Service (QoS) Information
DWDM (MUX/DEMUX)
 Throughput :
 Bandwidth:

Gy Online Diameter Interface (supported through ECS)
This is an optional Diameter protocol-based interface over which the GGSN communicates
with a Charging TriggerFunction (CTF) server that provides online charging data
Provides an online charging interface that works with the ECS deep packet inspection
feature
Charges online charging of network / user sessions: voice calls, IP CAN bearers, IP CAN
session or IMS sessions
Diameter – RFC 6733/ 3588/5516 (RADIUS auth evolved)
DCCA (Diameter Credit-Control Application)
ECS (Enhanced Charging Service)
CTF (Charging Trigger Function)
GGSN-CTF(OCS)
Allow customer traffic can be gated and billed in an "online" or "prepaid" style
Both time- and volume-based charging models are supported
In all of these models, differentiated rates can be applied to different services based on
shallow or deep packet inspection
DWDM (MUX/DEMUX)
 Throughput :
 Bandwidth:

Gz Offline GTP’ (GTP Prime) Interface
The off-line (CDR-based) charging interface between the GGSN and the Charging System
GTP’ (GTP Prime) - very similar to original GTP
CRF (Charging Rules Function)
GGSN-CRF
CDR (Call Detail Record)
DWDM (MUX/DEMUX)
 Throughput :
 Bandwidth:

Gxx (Gxc/Gxa) Diameter Interface
Bearer Binding and Event Reporting Function (BBERF) –PCRF related
Tandem Diameter Routing Agents (DRA)/Proxies/Relay Agents/Redirect Agents
PCRF (Policy Control and Charging Rules Function)
PCRF-Serving Gateway (SGW) Gxc interfaces in LTE Evolved Packet Core (EPC) networks
PCRF-Access Network Gateway (AGW) Gxa interfaces in trusted IP-CAN
IP Connectivity Access Networks (IP-CAN)
Gxx – 3GPP TS 23.203 and TS 29.212
Diameter – RFC 6733, RFC 3588 and RFC 5516
SCTP – RFC 4960
TCP – RFC 793
SGW-(Gxc)-PCRF-(Gxa)-AGW
 Capabilities/Services (Gxx procedures):
Bearer control mode selection
Provisioning of Gxx event triggers
QoS rules request
QoS rules provision
Gateway control session termination
Request of gateway control session termination
Capabilities/Services )
 Capabilities/Services (PCRF procedures based on configurable subscriber profiles/PCC rules):
Responds to requests and reports from BBERFs
Register or cancel event triggers in the BBERF
Install, modify, or remove QoS rules in the BBERF
DWDM (MUX/DEMUX)
 Throughput :
 Bandwidth:

AAA (optional) interface, DHCP interface
AAA is the interface used by the GGSN to communicate with an authorization,
authentication and accounting (AAA) server on the network
The system GGSN communicates with the AAA server using the Remote Authentication
Dial In User Service (RADIUS) protocol
DHCP is the interface used by the GGSN to communicate with a Dynamic Host Control
Protocol (DHCP) Server
RADIUS (Remote Authentication Dial In User Service) auth prot
DHCP (Dynamic Host Control Protocol)
GGSN-AAA, GGSN-DHCP
AAA is an optional interface that can be used by the GGSN for subscriber PDP context
authentication and accounting
The system can be configured as DHCP-Proxy or DHCP Client to provide IP addresses to
MS on PDP contexts activation the DHCP server dynamically
DWDM (MUX/DEMUX)
 Throughput :
 Bandwidth:

Lg MAP Interface (GPRS/UMTS)
UMTS (Universal Mobile Telecommunication System)/ UTRAN (UMTS Terrestrial Radio Access Network)
GMLC (Gateway Mobile Location Centre)=LCS Gateway-HLR/HSS/VMSC/SGSN/MSC
SMLC (Serving Mobile Location Server)-server used for the locations calculation, extracts
data from LMU (when present) or the network :TA(Time Advance, 2G)/Propagation Delay
The Lg Interface enable LCS (Location Services) in the GPRS/UMTS
Location based services/Emergency Services, rely upon LCS which provide support for
specialized mobile location services for operators/subscribers/3rd party service providers
LCS are also used to optimize network performance/ enhance network self-optimization
A-GPS(Assited GPS)/CELLID+RTT(Round-Trip Time)/LMU (Location Mounted Unit)
GPS(Global Positioning System)/ TOA= ( [ RTT ] – [ UE Rx-Tx time difference ] ) / 2
OTDOA(Time-Difference Of Arrival)- needs new NE called LMU for each monitored cell
A-GPS=Mobile-based(ME gets sattelite-data from its cell), CELLID/ TDOA =network-based
RFPM (Radio Frequency Pattern Match) Positioning – uses MMR (Mobile Measurements
Reports) with information such as signal strength, signal to noise ratio and delay
MAP-3GPP TS 29.002/TCAP-ITU-T Q.773/SCCP-ITU-T Q.711-714/M3UA-RFC 4666
SCTP-RFC 4960/User-Plane Loc Prot: A-GPS(Assisted Global Positioning System) SUPL
Control-Plane Location Prots:RRLP(GSM)/TIA 801( cdma2000)/RRC (UMTS)/LPP (LTE)
2.5-2.9 Gen (EGPRS/EDGE GERAN) /3G (UMTS UTRAN)/4G(LTE E-UTRAN)
SGSN-GMLC(SMLC)
 Capabilities/Services (Mobile Application Services):
MAP-Provide-Subscriber-Location, used by a GMLC to request the location and optionally,
velocity, of a target UE
MAP-Subscriber-Location-Report – used by a SGSN to provide the location of a target UE
to a GMLC
DWDM (MUX/DEMUX)
 Throughput :
 Bandwidth:

Gmb Interface (Multimedia Broadcast Multicast Services)
Point-to-multipoint interface specification for existing/ upcoming 3GPP cellular networks
Provide efficient delivery of broadcast and multicast services
Works both within a cell as well as within the core network
Defines transmission via single-frequency network configurations for broadcast TX across
multiple cells
Cost saving and new revenue source for operators (MNOs)
GERAN MBMS offers between 32 kbit/s and 128 kbit/s. Up to 4 GSM timeslots may be used
for one MBMS bearer in the downlink direction. The actual data rate per Traffic Slot
depends on network dimensioning
UTRAN MBMS offers up to 256 kbit/s per MBMS Bearer Service and between 800 kbit/s
and 1.7 Mbit/s per cell/band. The actual cell capacity depends on the UE capabilities
MBMS (Multimedia Broadcast Multicast Services)
3GPP (Third Generation Partnership Project) UMTS release - 3rd quarter of 2004
eMBMS/LTE Broadcast (Evolved Multimedia Broadcast Multicast Services) - 4G USA 2013
eMBMS has been standardized in various groups of 3GPP as part of LTE release 9
Generation (RFC-ID):
GGSN–BM-SC
Mobile TV/ Radio Broadcasting /Live Streaming Video Services /File Delivery
Emergency Alerts / Mobile Services alike RSOE EDIS(HUN)/GDACS(UN)/SADN(BRA)
The LTE version of MBMS, referred to as Multicast-broadcast single-frequency
network (MBSFN), supports broadcast only services and is based on a Single Frequency
Network (SFN) based OFDM waveform and so is functional similar to other broadcast
solutions such as DVB-H, -SH and –NGH
The MBMS feature is split into the MBMS Bearer Service and the MBMS User Service and
defined to be offered over UTRAN (WCDMA/TD-CDMA/TD-SCDMA) and LTE (eMBMS)
The MBMS Bearer Service includes a Unicast and a Broadcast Mode. MBMS Operation On-
Demand (MOOD) allows dynamic switching between Unicast/Broadcast over LTE, based
on configured triggers. MBMS Bearer Service uses IP multicast addresses for the IP flows
DWDM (MUX/DEMUX)
 Throughput :
 Bandwidth:

References
 Global System for Mobile communication (GSM) protocol family
Accessed March 18th, 2018
https://wiki.wireshark.org/GsmProtocolFamily
 5G & LTE Latin America 2018 White paper
Acessed April 1st, 2018
https://get.knect365.com/5g-latam/5g-service-and-use-
cases/?_ga=2.11200816.58299456.1522575672-388561131.1522575672
 Developing Solutions dsTest Network Testing Solutions and Interfaces
Acessed April 3rd, 2018
https://www.developingsolutions.com/products/
 PC, APC, SPC, UPC e Flat Polishing
Accessed April 3rd, 2018
http://www.inforteltelecom.com.br/?p=4392
 Cianet CWDM
https://www.cianet.com.br/cwdm-entenda-as-caracteristicas-dessa-tecnologia/
 Introduction of BiDi Transceivers
http://www.sopto.com/fiber_transceivers_learning/article-3573.shtml
 GBIC vs SFP
http://www.fiber-optic-transceiver-module.com/when-its-best-to-use-gbic-
and-when-to-use-sfp.html
 C Band Amplifiers, BOAs and SOAS
https://www.thorlabs.de/newgrouppage9.cfm?objectgroup_id=3901
 Single Mode vs Multi-Mode Fiber Optical Cable
https://www.multicominc.com/training/technical-resources/single-mode-vs-
multi-mode-fiber-optic-cable/
 Conectores e splicing - Redes, Guia Prático 2ª Ed. (Atualização)
https://www.hardware.com.br/livros/redes/conectores-splicing.html

 16 Types of Fiber Optic Connectors to Choose From
Accessed April 5th, 2018
http://www.ad-net.com.tw/16-types-fiber-optic-connectors-choose/
 Low versus no water peak in optical fiber
http://www.lightwaveonline.com/articles/print/volume-25/issue-
9/technology/low-versus-no-water-peak-in-optical-fiber-54889222.html
 What is the difference between ICCID, IMSI and IMEI numbers?
https://www.quora.com/What-is-the-difference-between-ICCID-IMSI-and-
IMEI-numbers
 What is LCS (and LBS)?
http://www.telecomhall.com/what-is-lcs-and-lbs.aspx
 Gb Interface
http://etutorials.org/Mobile+devices/gprs+mobile+internet/Chapter+3+Overvie
w+of+GPRS/Gb+Interface/
 EDGE for Mobile Internet
Emmanuel Seurre, Pierre-Jean Pietri, Patrick Savelli
 GSM/EDGE - Evolution and Performance
Mikko Saily/Guillaume Sébire/Dr. Eddie Riddington
 Mobile Backhaul
Juha Salmelin/Esa Metsälä
 GMM
http://etutorials.org/Mobile+devices/gprs+mobile+internet/Chapter+7+Signalin
g+Plane/GMM/
 SGSN-to-GGSN (Gn) and GGSN-to-PDN (Gi) Interface
https://www.globalspec.com/reference/63085/203279/chapter-10-sgsn-to-
ggsn-gn-and-ggsn-to-pdn-gi-interface

 SGSN-to-GGSN (Gn) and GGSN-to-PDN (Gi) Interface
https://www.globalspec.com/reference/63085/203279/chapter-10-sgsn-to-
ggsn-gn-and-ggsn-to-pdn-gi-interface
 GGSN Support in GPRS/UMTS Wireless Data Services
https://www.cisco.com/c/en/us/td/docs/wireless/asr_5000/21/GGSN/21-GGSN-
Admin/21-GGSN-Admin_chapter_01.pdf
 RSOE EDIS
http://hisz.rsoe.hu/alertmap/index2.php
 Who created GSM?
http://www.gsmhistory.com/who_created-gsm/

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