3. The standard defines the procedures and protocol by which network elements in the public switched telephone network (PSTN) exchange information over a digital signaling network to effect wireless (cellular) and wireline call setup, routing and control.
4.
5. wireless services such as personal communications services (PCS), wireless roaming, and mobile subscriber authentication
34. An single pair of STPs could be partitioned to support all or any layersUsing layers to separate networks
35. Signaling Interconnection RSTP D Links E Links LSTP LSTP SCP C Links A Links B-Link Quad SSP SSP LSTP LSTP Link Types: Access (A-Links): Connects STPs with SSPs, SCPs or MSC (Message Switching Center) Bridge (B-Links): Connects STPs Cross (C-Links): Connects mated STPs Diagonal (D-Links): Connects regional/local STPs to primary STPs Extended Links (E-Links): Connects SSPs , SCPs or MSC to alternate STPs Fully-Associated (F-Links): Connects SSPs
36. Linksets Combined Linksets Linkset 1 Linkset 3 Linkset 2 Linksets: Group of links between two nodes in the network Links are deployed in numbers to the power of 2 (1, 2, 4, 8) Traffic is loadshared over all link in the linksets Linkset size is limited by the protocol being used Combined linksets between STP pairs allow for loadsharing over both nodes to increase redundancy.
37. Point Codes Point Codes: Each signaling point in a SS7 network is assigned a unique point code Point code structure: ITU - 14 bit Point code ANSI - 24 bit Point code China - 24 bit Point code Japan - 16 bit Point code ITU Point Code: Basic: 14 International: 3 (Zone) - 8 (Area Network) - 3 (Signaling Point) Austria: 5 (Zone) - 4 (Region) - 5 (Signaling Point) China: 4 (Zone) - 7 (Exchange) - 3 (Signaling Point) Germany: 4 (Num Area) - 3 (HVST) - 4 (KVST) - 3 (Signaling Point) Node Identifiers: Origination Point Code (OPC) Destination Point Code (DPC) 0-1-0 1-1-0 3-3-3
38. Routesets Routesets Routes are defined between paths to a specific DPC A collection of Routes are defined as a Routeset Multiple Routes in a Routeset ensure that redundancy is build into the product. Routes are costed (Less expensive routing) 0-1-0 0-1-0 1-1-0 1-1-0 3-3-3 3-3-3
39. Subsystems Numbers/GTT Subsystem Number (SSN) Uniquely identifies an application residing on a destination point; typically an SCP database. Global Title Translation (GTT) Global Title Translation(GTT) provide specific information with regards to the Destination Point Code of the location of the application.
41. SS7 Protocol Stack The hardware and software functions of the SS7 protocol are divided into functional abstractions called "levels". These levels map loosely to the Open Systems Interconnect (OSI) 7-layer model defined by the International Standards Organization (ISO).
42. SS7 Protocol SS7 Protocol Layer Message Transfer Part (MTP) Level 1 Message Transfer Part (MTP) Level 2 Message Transfer Part (MTP) Level 3 Signal Connection Control Part (SCCP) Transaction Capabilities Part (TCAP) Key Protocol Specifications ITU Specifications: White Book (1992) Q701-Q709 (MTP), Q710-Q716 (SCCP), Q75x (Measurements) ETSI Specifications: 300 008 (MTP), 300 009 (SCCP) ANSI Specifications: GR-82, GR-246
46. Message Transfer Point (MTP):Level 3 MTP Level 3 Network level Message routing and network management Most effective message route between two signaling points Rerouting traffic away from failure Notification to all network to ensure minimal impact during failure modes (congestion control).
48. SCCP Layer Provides connectionless and connection-oriented network services. Where MTP route messages to a signaling point, SCCP will determine an application at that point. Determines network address and relay the information to MTP layer SCCP also provides the means by which an STP can perform global title translation (GTT), a procedure by which the destination signaling point and subsystem number (SSN) is determined from digits (i.e., the global title) present in the signaling message.
52. The ISDN User Part (ISUP) defines the protocol and procedures used to set-up, manage, and release trunk circuits that carry voice and data calls over the public switched telephone network (PSTN). ISUP is used for both ISDN and non-ISDN calls.
59. Providing the links between the STPs are a combined linkset the messages are loadshared across the links.
60.
61. STP A notifies it associated links (Directly connected links) to not send message to the SSP if another path is available - Restricted
62. All messages are now sent from SSP (0-1-0) through STP C to STP B.
63.
64. All messages are now sent from SSP (0-1-0) through STP C to STP A to STP B - C link routing
65.
66. STP A and B notifies all nodes (associated and quasi-associated) to not send message to the SSP - Prohibited
67.
68. Country A NI=2 Country A NI=2 Country C NI=3 Country B NI=2 Network Indicator International Network Indicators (“0” and “1”are not regulated and for use at the International boundaries) National Network Indicators (“2=National”, and “3=National spare”) are left up to National networks to define. Nationally standardized Network Indicator values has started to cause interworking issues. Global Operators that operate in more than one country are facing NI conflicts when trying to connect to different National and International networks each defining their own NI usage requirements. NI 0 International NW 1 Spare (international use) 2National Network 3 Reserved for National use ? Needs are proprietary; Conflicts and needs can be resolved at a gateway STP
81. Universal Mediation Platform - Adds ability to control requests from another operator’s networks. Guards against inappropriate and/or illegal use of host network and services. Screens ISUP and TCAP messages and their content.
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