This document provides an overview of Signaling System No. 7 (SS7) architecture and protocols. It describes the layers of the SS7 protocol stack including the Message Transfer Part (MTP), Signaling Connection Control Part (SCCP), and Transaction Capabilities Application Part (TCAP). It also discusses SS7 node types, link types, and signaling scenarios. Finally, it provides details on various SS7 application protocols used in cellular networks, such as the Mobile Application Part (MAP) protocol.

1. Mobile Core Network

2. Introduction to SS7
Chapter5
Signaling Scenarios
Chapter6
SIGTRAN (SS7oIP)
Chapter7

3. Introduction to SS7
Chapter 5

4. Signaling Definition
Introduction to SS7
• Signaling is the control
plane messages used for
communication between
different entities to
request or transfer any
information such as
requesting the busy or
free state of a device,
occupy or release a
device, etc…
Chapter 5

5. Signaling in Communication Networks
Chapter 5 Introduction to SS7
Signaling
Access Signaling Trunk Signaling
Channel Associated Signaling
Common Channel Signaling
Subscriber Line Signaling
Digital Subscriber Signaling

6. OSI Reference Model
Introduction to SS7
Application Application
Presentation Presentation
Session
Transport
Network
Data Link
Physical
Session
Transport
Network
Data Link
Physical
System A System B
User User
Physical Circuit
Peer-to-Peer Protocols
Chapter 5

7. Data Processing in OSI Layers
Introduction to SS7
Application Application
Presentation Presentation
Session
Transport
Network
Data Link
Physical
Session
Transport
Network
Data Link
Physical
System A System B
User User
Physical Circuit
110111 BITS 100110
TL DLH
DATA
NH
DATA
DATA TH
DATA SH
DATA PH
DATA AH
Sending Process Receiving Process
Chapter 5

8. Relationship between OSI and SS7
Introduction to SS7
User parts
Physical
Network
Transport
Session
Presentation
TCAP
MTP2
Data link
MTP1
SCCP
MTP3
ASEs
Application
NSP
MTP
ASE
MTP
NSP
SCCP
TCAP
Application Service Element
Message Transfer Part
Network Service Part
Signaling Connection Control Part Transaction
Capabilities Application Part
2
3
4
5
6
7
1
OSI Model SS7 Model
Chapter 5

9. Signaling Network Elements
Introduction to SS7
Chapter 5
SP 2
SP 3
Signaling Link 1
Signaling Link 0
Link Set
Link Set
set to SP 2
ly or
P 3
SP Signaling Point
SL Signaling Link
LS Link Set
SR Signaling Route
SRS Signaling Route Set
Signaling Link 0
Signaling Link 1
Link Set
Link Set
Route Set to SP 2
• Directly or
• Via SP 3

10. SS7 Node Types
Introduction to SS7
Chapter 5
1. SSP (Service Switching Point)
• Originate and Terminate Signaling Messages
• Functions as Circuit Switching node
2. STP (Signaling Transfer Point)
• Relay Signaling Messages (acts as a Router in SS7)
• STPs can be deployed in Three Levels:
 Local, National and International STPs

11. SS7 Node Types
Introduction to SS7
Chapter 5
3. SCP (Service Control Point)
• Provides access to Applications such as Databases
• The protocol used to interface with a database is TCAP
4. SRP (Specialized Resource Point)
• Provide Circuit Switching capabilities to SCP
• Mostly used for Tones and Announcements related to SCP

12. STPs Hierarchy
Introduction to SS7
Signaling to International Destinations
Chapter 5
SSP SSP SSP SSP SSP
STP STP STP STP
iSTP
iSTP

13. SS7 Link Types
Introduction to SS7
Chapter 5
• Type A (Access Link)
 Connect “SSP to STP” or “SCP/SRP to STP”
• Type B (Bridge Link)
 Connect Paired STPs to another Paired STPs
• Type C (Cross Link)
 Connect one STP to its pair STP to form a Paired STPs

14. SS7 Link Types
Introduction to SS7
Chapter 5
• Type D (Diagonal Link)
 Connect a Paired STPs to a Paired STPs in another level
• Type E (Extended Link)
 Connect SSPs to alternate or remote STPs for redundancy
• Type F (Fully Associated Link)
 Connect two SSPs when significant traffic flows between
them

15. Another network
SSP
STP
STP
STP
STP
STP
STP
SS7 Link Types
Introduction to SS7
Chapter 5
A-link C-link B-link D-link
E-link
F-link
SSP
SSP
SSP
SRP
SCP

16. SS7 Message Types
Introduction to SS7
Chapter 5
• MSU (Message Signaling Unit)
 Carry signaling information between user parts
• LSSU (Link Status Signaling Unit)
 Carry link status information
• FISU (Fill-in Signaling Unit)
 Serves as the heartbeat when no MSUs or LSSUs to be sent
 Ensures 100% link occupancy by signaling units at all times

17. SS7 Suite in GSM
Introduction to SS7
MAP
Chapter 5
Users of Signaling System No. 7
TCAP
SCCP
MTP
CAP RANAP BSSAP ISUP
BSSAP Base Station Subsystem Application Part
CAP CAMEL Application Part
ISUP ISDN User Part
MAP Mobile Application Part
MTP Message Transfer Part
SCCP Signaling Connection Control Part
TCAP Transaction Capabilities Application Part
RANAP Radio Access Network Application Part

18. MTP 1
Introduction to SS7
MTP 1 (Physical Layer)
• SLI (Signaling Link Interface) handles the SS7 Stack
• Physical connectivity to transmit the signals (PCM-link)
• Pins Layout of the physical connection (Tx, Rx, Power, Earth)
• Encoding/Decoding of data based on Transmission Media Type
Chapter 5

19. MTP 2
Introduction to SS7
MTP2 (Data Link Layer)
• Form the MAC (Medium Access Control) of the Data Link Layer
• Logical connectivity (E1, STM, Time Slots)
• Reliable data transfer between physical interconnected devices
• Framing, Error Detection/Correction and Link Status messages
• Time Slots with signaling capabilities are called Signaling Links
• Signaling Links (SL) are numbered from 0—15 (SLCs)
• SLCs form the Link Set (LS) between two Signaling Points (SPs)
Chapter 5

20. MTP 3
Introduction to SS7
MTP 3 (Data Link Layer)
• Form the LLC (Logical Link Control) of the Data Link Layer
• Signal messages to reach intended destination
• Transportation of signal messages (MSU: Message Signal Unit)
• Addressing of Local and Adjacent Signaling Points
• MTP3 Address is called “Signaling Point Code”
Chapter 5

21. MTP 3
Introduction to SS7
MTP 3 (Data Link Layer)
• MTP3 Routing Table is used to route the messages
• Each Signaling Route (SR) can be formed from one or more LS
• More than one SR form a Signaling Route Set (SRS)
• Transmission Mode used is based on Network Topology:
 Load-Share mode
 Active/Standby mode
Chapter 5

22. Signaling Point Code
Introduction to SS7
SPC is composed of two parts:
1. Network Indicator
• NI=0: International Network
• NI=1: Reserved for future use
• NI=2: National Network
• NI=3: Local Network
2. Point Code
• Assigned by the Operator to each Signaling Point (OWNSP)
Chapter 5

23. SS7 SIGNALING POINT DATA
SPID
OWNSP
OWNSP
SP
0-1007
0-1111
2-6017
2-6025
2-6026
2-6050
2-6113
KHTMSC
SCCPGW
KHTMSC
MANBSC
MANRNC
OMDMSC
WMDMSC
END
Signaling Points Definition in KHTMSC
Introduction to SS7
Chapter 5

24. Functional Levels of the MTP
Introduction to SS7
Level 3 Signaling Network Functions
Signaling message handling
Message discrimination
Message routing
Message distribution
Signaling network management
Signaling link management
Network control
Level 2 Signaling Link Functions
Signal unit delimitation
Signal unit alignment
Error detection
Acknowledgements
Sequence numbers
Error correction
Buffer functions
Signaling terminal
Initial alignment
LSSU messages
Congestion ind. to level 3
Link monitoring
Level 1 Signaling Data Link
Interface to and from switching and transmission equipment.
• typically 64 kbps digital signaling channel (one TS on PCM line)
• other types of links, for example: analogue, bit rate 4.8 kbps or higher
Chapter 5

25. MTP3 Message Handling
Introduction to SS7
Message
Distribution
Message
Discrimination
Message
Routing
Signaling
Message
Handling
MTP L2
User Part MTP L3
User
Parts
Signaling
Link
Functions
Chapter 5
STP

26. MTP3 Routing Table
Introduction to SS7
Chapter 5
MTP3 Routing Table in node 2-7871
Destination LS Priority
2-311 2-311 1
2-309 2
2-1610 2
2-309 2-309 1
2-311 2
2-807 2-311 1
2-309 1
and so on
2-311
2-1610
2-309
2-807
2-7871

27. Signaling “Rules of Thumb”
Introduction to SS7
• Maximum number of SLCs between two SPCs
(Signaling Point Codes) are 16 SLC
• Number of SLCs should be a power of 2
e.g. 1, 2, 4, 8, 16 (2n)
Chapter 5

28. SCCP
Introduction to SS7
SCCP (Signaling Connection Control Part)
• “Adds-on protocol” makes SS7 (MTP) able of End-to-End
network signaling
• The combination of the MTP and the SCCP is called the
Network Service Part (NSP)
• Used for Non-Circuit related signaling (LU/HO/Charging)
• Provide both Connection-Oriented/Connection-Less services
• SCCP End-to-End Address is called “Global Title”
Chapter 5

29. SCCP
Introduction to SS7
SCCP (Signaling Connection Control Part)
• All nodes involved in E2E Signaling must have a GT
• GT is based on E.164 to be Internationally Routed
• SCCP also defines the Application Part that Protocol
• SSN (Subsystem Number) is used to define each application
running on the Signaling Point
• Provide the Network/Transport Layer functions of the OSI
Model
Chapter 5

30. SCCP CO and CL Services
Introduction to SS7
Chapter 5
MTP
SCCP
CL CO ISUP
MAP INAP
RANAP TCAP BSSAP
CO=Connection Oriented
CL=Connection Less

31. SCCP Addressing
Introduction to SS7
MTP
Routing
Table
OPC DPC
Calling
Address
Called
Address
GlobalTitle SSN
AI
NA
NP
TT
MAP
SCCP TCAP
Chapter 5

32. SCCP Address Elements
Introduction to SS7
Address length
Address indicators
Signaling Point Code
Global Title
SCCP Subsystem Number
Bit 1: SPC included (1) or not (0)
Bit 2: SSN included (1) or not (0)
Bit 7: Routing indicator, Route on SSN (1) or GT (0)
TT=0
NP=1 E.164 (ISDN)
NP=7 E.214 (MGT)
ES=1 BCD, odd number of digits
ES=2 BCD, even number of digits
Translation Type
Numbering Plan
Nature of address
Address information
Encoding Scheme
NA=3 National
NA=4 International
6 MAP (HLR)
7 MAP (VLR)
8 MAP (MSC)
9 EIR
10 AuC
142 RANAP
146 CAP
149 MAP (SGSN)
254 BSSAP
ITU-T Signaling
Chapter 5

33. SCCP Own GT and Cooperating SPs
Introduction to SS7
Chapter 5
SCCP NETWORK CONFIGURATION DATA
SP SPID SP STATE
2-6025 MANBSC ALLOWED
SSN SUBSYSTEM STATE
254 ALLOWED
OWN CALLING ADDRESS DATA
NAT
1722100097
INT
491722100097
SP SPID SP STATE
2-6026 MANRNC ALLOWED
SSN SUBSYSTEM STATE
142 ALLOWED
SP SPID SP STATE
2-6050 OMDMSC ALLOWED
SSN SUBSYSTEM STATE
7 ALLOWED
8 ALLOWED
SP SPID SP STATE
2-6113 WMDMSC ALLOWED
SSN SUBSYSTEM STATE
6 ALLOWED
7 ALLOWED
8 ALLOWED
10 ALLOWED

34. Global Title Translation
Introduction to SS7
Chapter 5
AI=
0
NP= 1 (E.164)
NA= 4 (International)
TT=
4670123456
TT NP NA AI GTRC
0 1 4 44 1
0 7 4 44 1
0 1 4 46701 2
0 7 4 46701 2
0 1 3 701 2
0 1 4 48 3
0 7 4 48 3
GTRC DPC
1 2-101
2 2-201
3 2-301
4 OWNSP
MTP3 TRANSFER
DPC=2-201
AI Address Information
NA Nature of address
NP Numbering Plan
TT Translation Type
GTRC Global Title Routing Case
DPC Destination Point Code
OWNSP “Own” Signaling Point

35. TCAP
Introduction to SS7
TCAP (Transaction Capability Application Part)
• “Adds-on protocol” makes SS7 (SCCP) able of handle signaling
transactions with Databases
• Support queries/responses to/from Database
• Support add/modify/remove to/from Database
• Session within Database is maintained using “Transaction ID”
Chapter 5

36. TCAP
Introduction to SS7
Types of TCAP messages:
• Begin: Used to start a TCAP Session with another node
• Continue: Used to correlate messages within one TCAP Session
• End: Used to signal that an existing TCAP Session will be
normally terminated
• Abort: Used to signal that an existing TCAP Session will be
forcefully terminated due to an error in the transaction
Chapter 5

37. TCAP Structure
Introduction to SS7
Chapter 5
NSP
SCCP
MTP
MAP
TCAP
CAP INAP

38. Functional View of TCAP
Introduction to SS7
Chapter 5
SCCP
TC-user
TCAP
SCCP
TC-user
TCAP
Dialogue
Transaction
SCCP Network
End-to-End Signaling

39. Elements of TCAP Messages
Introduction to SS7
Chapter 5
Begin Originating Transaction ID
Dialogue Portion
Continue Originating Transaction ID
Destination Transaction ID
Dialogue Portion
End Destination Transaction ID
Dialogue Portion
Abort Destination Transaction ID
Abort reason
Dialogue Portion

40. SS7 Application Parts
Introduction to SS7
MAP (Mobile Application Part)
• Used for communication between PLMN Nodes and Databases
 MSC, VLR, HLR, AUC, EIR and SMSC
• Used for Registration, Authentication, Routing and “IMEI Check”
• Each MAP message must contain two components:
 Operation Code: defines the message type
 Message Information: include needed contents
Chapter 5

41. MAP Structure
Introduction to SS7
Chapter 5
TCAP
SCCP
MTP
Application Entities
MAP-HLR
ASE
SSN=6
MAP-VLR
ASE
SSN=7
MAP-MSC
ASE
SSN=8

42. MAP Messages
Introduction to SS7
-- call handling
sendRoutingInfo 22
provideRoamingNumber 4
resumeCallHandling 6
-- handover
prepareHandover 68
sendEndSignal 29
processAccessSignaling 33
forwardAccessSignaling 34
prepareSubsequentHandover 69
-- authentication
sendAuthenticationInfo 56
-- IMEI management
checkIMEI 43
-- subscriber management
insertSubscriberData 7
deleteSubscriberData 8
-- fault recovery
reset 37
forwardCheckSS-Indication 38
restoreData 57
-- operation and maintenance
activateTraceMode 50
deactivateTraceMode 51
sendIMSI 58
-- location registration
updateLocation 2
cancelLocation 3
purgeMS 67
sendIdentification 55
-- supplementary service handling
registerSS 10
eraseSS 11
activateSS 12
deactivateSS 13
interrogateSS 14
processUSSD-Request 59
unstructuredSS-Request 60
unstructuredSS-Notify 61
registerPassword 17
getPassword 18
-- short message service
sendRoutingInfoForSM 45
mo-forwardSM 46
mt-forwardSM 44
reportSM-DeliveryStatus 47
informServiceCentre 63
alertServiceCentre 64
readyForSM 66
-- provide subscriber info
provideSubscriberInfo 70
-- any time interrogation
anyTimeInterrogation 71
Chapter 5

43. SS7 Application Parts
Introduction to SS7
CAP (CAMEL Application Part)
• Signaling protocol used in the Intelligent Network (IN)
 MSC to SCP
 SCP to SRP
• CAMEL (Customized Applications for Mobile Enhanced Logic)
• Allow for the implementation of Prepaid control services:
 Credit Control for MO/MT Call/SMS and GPRS Data
 Free Toll Numbers, Free URLs
• Built based on its predecessor INAP (IN Application Part)
Chapter 5

44. SS7 Application Parts
Introduction to SS7
ISUP (ISDN User Part)
• Circuit-Related protocol used for Link-to-Link signaling
• Setup, Maintain and Release Calls in PLMN and ISDN
• Its predecessor “TUP” was used in PSTN (Telephony User Part)
• Circuits are identified using CICs (Circuit Identification Code)
Chapter 5

45. Circuit-related Vs. Non-circuit-related
Introduction to SS7
MTP
ISUP
Traffic
control
MTP
ISUP
Traffic
control
MTP
ISUP
Traffic
control
Application
SCCP user
MTP
SCCP
MTP
SCCP
MTP
SCCP
Application
SCCP user
Routing of
SCCP message
Link-by-Link Circuit-Related Signaling
End-to-End Non-Circuit-Related Signaling with SCCP
Chapter 5

46. ISUP Call Flow
Introduction to SS7
S P A S P B S P C S P D
I A M
I A M
I A M
A C M
A C M
A N M
A N M
... c o n v e r s a t i o n ...
R E L
R E L
R E L
R L C
R L C
R L C
I n i t i a l A d d r e s s
M e s s a g e
A d d r e s s C o m p l e t e
M e s s a g e
A n s w e r
M e s s a g e
R e le a s e
R e l e a s e
C o m p l e t e
Chapter 5
A C M
A N M

47. Traffic “Rule of Thumb”
Introduction to SS7
• Maximum number of CICs between two SPCs
(Signaling Point Codes) is 4096 (2 STMs)
• One STM is equivalent to 64 E1s
 1 of the 64 E1s is used for Synchronization
 Only 63 E1 can be used to carry Traffic
Chapter 5

48. SS7 Application Parts
Introduction to SS7
BSSAP (Base Station Subsystem Application Part)
• Signal messages between MSC and BSC
• BSSAP is used to tunnel two different applications:
1. BSSMAP (BSS Mobile Application Part)
 Used by MSC to communicate BSC related messages
 Use Connection-Less method
2. DTAP (Direct Transfer Application Part)
 Used by MSC to communicate MS related messages
 Sent to MS in Active Mode (Connection-Oriented)
Chapter 5

49. SS7 Application Parts
Introduction to SS7
RANAP (Radio Access Network Application Part)
• Signal messages between MSC and RNC
• Used to tunnel DTAP messages towards MS
 Used by MSC to communicate MS related messages
 Sent to MS in Active Mode (Connection-Oriented)
Chapter 5

50. Protocols Stack
Introduction to SS7
MAP
TCAP
SCCP
MTP3
MTP2
MTP1
ISUP
MTP3
MTP2
MTP1
BSSAP
SCCP
MTP3
MTP2
MTP1
Chapter 5

51. Signaling Scenarios
Chapter 6

52. IMSI Conversion to MGT
Signaling Scenarios
Chapter 6
MGT
IMSI
MSC
IMSI NUMBER SERIES
ANALYSIS
HLR

53. IMSI Conversion to MGT
Signaling Scenarios
Chapter 6
IMSI Number Series Analysis Data
IMSIS M NA
63401 5-24991 4
42003 5-96656 4
MCC MNC MSIN
CC NDC MSIN
translated translated
IMSI (E.212)
MGT (E.214)

54. Called GT Priority:
Signaling Scenarios
Chapter 6
1. Node Global Title (NGT)
 Can be used to route to any node
2. MSISDN
 Can be used to route only to HLR
3. Mobile Global Title (MGT)
 Can be used to route only to HLR

55. Authentication Request
MAP: Check IMEI Ack
Check Result: White List
SCCP: NP=1 TT=0 NA=4 AI=467070100078
HLR/AuC
Location Update (IMEI Check + Authentication)
EIR
MSC/VLR
MAP: Check IMEI
IMEI=520002512311030
SCCP: NP=1 TT=0 NA=4 AI=467070100001
MGT derived from IMSI used as called address
EIR address defined in MSC
Location Update Request
Signaling Scenarios
Chapter 6
MAP: Send Authentication Info Ack
RAND, SRES, Kc (Triplet)
SCCP: NP=1 TT=0 NA=4 AI=46707010099
MAP: Send Authentication Info
IMSI=420034000086893
SCCP: NP=7 TT=0 NA=4 AI=966564000086893
Old
MSC/VLR

56. Location Update Response
MAP: Update Location
IMSI=420034000086893
SCCP: NP=7 TT=0 NA=4 AI=966564000086893
MAP: Insert Subscriber Data
IMSI,MSISDN, Basic/Supplementary Services
SCCP: NP=1 TT=0 NA=4 AI=467070100099
MAP: Insert Subscriber Data Ack
SCCP: NP=1 TT=0 NA=4 AI=467070100068
HLR/AuC
Location Update (Update Location + ISD)
MSC/VLR
MGT derived from IMSI used as called address
Authentication Response
Signaling Scenarios
Chapter 6
MAP: Update Location Ack
HLR Number (GT)
SCCP: NP=1 TT=0 NA=4 AI=467070100099
Old
MSC/VLR
MAP: Cancel Location
IMSI=420034000086893
SCCP: NP=1 TT=0 NA=4 AI=467070100037
MAP: Cancel Location Ack
SCCP: NP=1 TT=0 NA=4 AI=467070100099
EIR

57. HLR
SCCP Addressing during a Call to an MS
GMSC
MAP: Provide Roaming Number
IMSI=420034000086893
SCCP: NP=1 TT=0 NA=4 AI=467072100088
Dialed MSISDN used as called address
MSC/VLR address received at location updating
Incoming Call to MS
Signaling Scenarios
Chapter 6
MSC/VLR
MAP: Provide Roaming Number Ack
MSRN=467079999223
SCCP: NP=1 TT=0 NA=4 AI=467072100090
MAP: Send Routing Info Ack
MSRN=467079999223
SCCP: NP=1 TT=0 NA=4 AI=467072100038
MAP: Send Routing Info
MSISDN=467074453422
SCCP: NP=1 TT=0 NA=4 AI=467074453422

58. Status: Sent
HLR/AuC
SCCP Addressing during SMS-MO
SMSC
MSC/VLR
SMSC GT is received from MS in SMS-MO Request
SMS-MO Request
Signaling Scenarios
Chapter 6
MAP: MO-Forward SM Ack
SMS Status: Sent
SCCP: NP=1 TT=0 NA=4 AI=966564567890
MAP: MO-Forward SM
A#, B#, SMSCGT, SMS Text
SCCP: NP=1 TT=0 NA=4 AI=966561234567
MSC/VLR

59. Status: Delivered
MAP: Send Routing Info for SM ACK
MSC/VLR GT=966561234888
SCCP: NP=1 TT=0 NA=4 AI=966561234567
HLR/AuC
SCCP Addressing during SMS-MT
SMSC
MSC/VLR
MAP: Send Routing Info for SM
MSISDN=467074453422
SCCP: NP=1 TT=0 NA=4 AI=467074453422
MSC/VLR GT is received from HLR in SRI-for-SM Ack
Dialed MSISDN used as called address
Paging Response
Signaling Scenarios
Chapter 6
MSC/VLR
Paging Request
SMS Delivered
SMS Sent
MAP: MT-Forward SM
A#, B#, SMSCGT, SMS Text
SCCP: NP=1 TT=0 NA=4 AI=966561234888
MAP: MO-Forward SM Ack
SMS Status: Delivered
SCCP: NP=1 TT=0 NA=4 AI=966564567890
MAP: MT-Forward SM Ack
SMS Status: Delivered
SCCP: NP=1 TT=0 NA=4 AI=966561234567

60. SS7 Sample Trace (MAP Update Location)
Signaling Scenarios
Chapter 6
Frame 239: 136 bytes on wire (1088 bits)
[Protocols in frame: mtp2:mtp3::sccp:tcap:gsm_map]
Message Transfer Part Level 2
Backward sequence number: 113
Backward indicator bit: 0
Forward sequence number: 56
Forward indicator bit: 0
Signaling Link Selector: 13
Message Transfer Part Level 3
Service information octet
Network indicator: National network (0x02)
Service indicator: SCCP (0x03)
Routing label
DPC: 6113
OPC: 6050

61. SS7 Sample Trace (MAP Update Location)
Signaling Scenarios
Chapter 6
Signalling Connection Control Part
Calling Party address (11 bytes)
SubSystem Number: VLR (Visitor Location Register) (7)
Global Title 0x4 (9 bytes)
Translation Type: 0x00
Numbering Plan: E.164 (0x01)
Encoding Scheme: BCD, even number of digits (0x02)
Nature of Address Indicator: International number (0x04)
Calling Party Digits: 249912020020
Called Party address (13 bytes)
SubSystem Number: HLR (Home Location Register) (6)
Global Title 0x4 (11 bytes)
Translation Type: 0x00
Numbering Plan: E.214 (0x07)
Encoding Scheme: BCD, odd number of digits (0x01)
Nature of Address Indicator: International number (0x04)
Called Party Digits: 966567240825829

62. SS7 Sample Trace (MAP Update Location)
Signaling Scenarios
Chapter 6
Transaction Capabilities Application Part
Begin
Source Transaction ID: d6140140
GSM Mobile Application
Component: invoke (1)
Operation Code: UpdateLocation (2)
IMSI: 420037240825829
MSC-Number: 249912020020
VLR-Number: 249912020020

63. SIGTRAN (SS7oIP)
Chapter 7

64. SS7 SIGNALING POINT DATA
SPID
OWNSP
SP
2-6017
2-6025
2-6026
2-6050
2-6113
KHTMSC
MANBSC
MANRNC
OMDMSC
WMDMSC
END
Using Multiple SPCs for Single SP
Chapter 7
SP
2-6018
2-6051
2-6114
OWNSP KHTMSC
OMDMSC
WMDMSC
SPID
SIGTRAN (SS7oIP)

65. High Speed Signaling
2 Mbpslink
Current C7 Signaling
2 Mbpslink
MSC MSC MSC MSC MSC
STP
High Speed
SignalingLinks
HIGH
Capacity
HLR
HIGH
Capacity
HLR
STP
HSL (High Speed Signaling Link)
SIGTRAN (SS7oIP)
Chapter 7

66. Traditional SS7 Networks
Chapter 7 SIGTRAN (SS7oIP)
Site
STP
MSC MSC MSC MSC STP
MSC MSC MSC MSC
Site
MSC
HLR
MSC
MSC
MSC
Site
STP
MSC MSC MSC MSC
Site
STP
MSC MSC MSC MSC
Site
MSC
HLR
MSC
MSC
MSC
Site
MSC
HLR
MSC
MSC
MSC
Site
MSC
HLR
MSC
MSC
MSC
Site

67. SS7 Networks using SIGTRAN
Chapter 7 SIGTRAN (SS7oIP)
Site
MSC MSC MSC MSC
Site
MSC MSC MSC MSC
Site
MSC
HLR
MSC
MSC
MSC
Site
MSC MSC MSC MSC
Site
MSC MSC MSC MSC
Site
MSC
HLR
MSC
MSC
MSC
Site
MSC
HLR
MSC
MSC
MSC
Site
MSC
HLR
MSC
MSC
MSC
IP

68. SIGTRAN Suite
Chapter 7 SIGTRAN (SS7oIP)
IP
Ethernet
M3UA
SCTP
SCCP
ISUP TCAP
BICC GCP
MAP CAP
RANAP

69. Sigtran Protocols Stack
MAP
TCAP
SCCP
M3UA
SCTP
IP
Ethernet
Physical
Chapter 7 SIGTRAN (SS7oIP)
RANAP
SCCP
M3UA
SCTP
IP
Ethernet
Physical
BICC
M3UA
SCTP
IP
Ethernet
Physical

70. SCTP 4-way Handshake Procedure
Chapter 7 SIGTRAN (SS7oIP)
SCTP Node 1 SCTP Node 2
PortID
SCTP entity
SCTP
PortID
SCTP entity
SCTP
IP1,IP2 IP3,IP4
IP Network
INIT
INIT ACK
COOKIE ECHO
COOKIE ACK
IP R
IP R
IP R
IP R
IP R
Create Association
(Destination, # Stream)

71. Sigtran Redundancy Mechanisms
Chapter 7 SIGTRAN (SS7oIP)
• IP level redundancy
 IP migration and Gateway Supervision
 IP path redundancy
 Transmission media redundancy
• SCTP level redundancy
 Multi-homed SCTP associations
• M3UA level redundancy
 M3UA routing redundancy

72. IP Level Redundancy
Chapter 7 SIGTRAN (SS7oIP)
MSC
SLI0 SLI1
Sw1 Sw2
Sw1 Sw2
MSC
3
1 3
MH SCTP EP
MH SCTP EP
Primary Path
Straight LSP used
for SCTP path (1)
LSP used for
SCTP path (3)
Router8
VRF
Router7
VRF
Router1
VRF
Router2
VRF
Router3
VRF
Router4
VRF
Router6
VRF
Router5
VRF
Straight LSP
Straight LSP
Forwarding
1
Act Stb
Default GW for
SLI0
Default GW for
SLI1
SS7 data Heart beat
• No SPOF (Single Point of Failure)
• Transmission media used in WAN are
from different Service Providers
• Gateway Supervision allow for Router
redundancy on the same LAN
• Two subnets (VLANs) can be used on
each site
• Site Router can be used for Inter-VLAN
routing

73. SCTP Level Redundancy
Chapter 7 SIGTRAN (SS7oIP)
SLI0
SLI1
MSC
IP 1
IP 2
SLI0
SLI1 MSC
IP 3
IP 4
IP Network
Multi-Homed SCTP End Point
IP Port
Multi-Homed
SCTP End Point
M3UA Route
(towards Multi-Homed
SCTP Association)
Traffic Path (Active)
Traffic Path (Stand-By)
Multi-Homed SCTP Association
M3UA M3UA
(Port 2905) (Port 2905)

74. M3UA Level Redundancy
Chapter 7
M3UA Routing Table in node 2-7871
Destination SAID Priority
2-311 2-311 1
2-309 2
2-1610 2
2-309 2-309 1
2-311 2
2-807 2-311 1
2-309 1
and so on
2-311
2-1610
2-309
2-807
2-7871
SIGTRAN (SS7oIP)

75. SIGTRAN Trace (MAP Update Location)
Chapter 7
Frame 1: 598 bytes on wire (4784 bits)
[Protocols in frame: eth:ip:sctp:m3ua:sccp:tcap:gsm_map]
Ethernet:
Source: Ericsson_27:83:b6 (00:30:88:27:83:b6)
Destination: Ericsson_20:11:9e (00:30:88:20:11:9e)
Type: IPv4 (0x0800)
Internet Protocol Version 4:
Version: 4
Differentiated Services Code Point: Assured Forwarding 11 (10)
Time to live: 63
Protocol: SCTP (132)
Source: 172.17.230.2
Destination: 172.18.0.184
SIGTRAN (SS7oIP)

76. SIGTRAN Trace (MAP Update Location)
Chapter 7
Stream Control Transmission Protocol:
Source port: m3ua (2905)
Destination port: m3ua (2905)
MTP 3 User Adaptation Layer
OPC: 4802
DPC: 2885
SI: SCCP (3)
NI: National network (2)
[MTP3 equivalents]
[OPC: 4802]
[DPC: 2885]
[NI: 2]
SIGTRAN (SS7oIP)

77. SIGTRAN Trace (MAP Update Location)
Chapter 7
Signalling Connection Control Part
Calling Party address (11 bytes)
SubSystem Number: VLR (Visitor Location Register) (7)
Global Title 0x4 (9 bytes)
Translation Type: 0x00
Numbering Plan: E.164 (0x01)
Encoding Scheme: BCD, even number of digits (0x02)
Nature of Address Indicator: International number (0x04)
Calling Party Digits: 249912020020
Called Party address (13 bytes)
SubSystem Number: HLR (Home Location Register) (6)
Global Title 0x4 (11 bytes)
Translation Type: 0x00
Numbering Plan: E.214 (0x07)
Encoding Scheme: BCD, odd number of digits (0x01)
Nature of Address Indicator: International number (0x04)
Called Party Digits: 966567240825829
SIGTRAN (SS7oIP)

78. SIGTRAN Trace (MAP Update Location)
Chapter 7
Transaction Capabilities Application Part
Begin
Source Transaction ID: d6140140
GSM Mobile Application
Component: invoke (1)
Operation Code: UpdateLocation (2)
IMSI: 420037240825829
MSC-Number: 249912020020
VLR-Number: 249912020020
SIGTRAN (SS7oIP)