E1-E2 / E2-E3 CFA SIGNALING IN TELECOM NETWORK & SSTP

E1-E2 / E2-E3 CFA SIGNALING IN TELECOM NETWORK & SSTP

TRUNK SIGNALING Signaling between two exchanges. Trunk signals can be classified into two types: Supervision Signals : To control and monitor the status of the transmission circuits. Examples : seizure signal and idle state signal. Address Signals : To transfer the specific subscriber information necessary to connect the calling party to the called party. Examples: Called party's directory number and the calling party's category.

Digital signaling Channel Associated signaling (CAS) Common Channel Signaling (CCS)

Channel Associated Signaling The location of the signaling information is related directly to the user voice/data. Ts 16 is used to carry signaling information related to the 30 voice data channels.

Common Channel Signaling (CCS) A channel is common for sending all the signaling information of a nos. of users on sharing basis. In this case also TS16 is normally used as common channel i.e. signaling link. All the 8 bits of time slot 16 are used for signaling / control information.

FEATURES OF CCS# 7 SIGNALING Internationally standardized (national variations possible) suitable for various communication services such as telephony, text, data services high performance and high reliability for message transfer signaling links always available, even during existing calls transfer rate of 64 kbit/s typical in digital networks

CCS#7 NODES Signaling points (SP) The SP / SEP is the source (originating point) and the sink (destination point) of signaling traffic. Signaling Transfer Points (STP) The STPs / STEPs switch signaling messages received to another STP or to a SP on the basis of the destination address. No call processing of the signaling messages occurs in a STP/STEP. A STP can be integrated in a SP (i.e. STEP) or can form a node of its own in the signaling network.

CCS#7 NODES Signaling links A channel of an existing transmission link (e.g. a PCM30 link) is used as the signaling data link. Generally, more than one signaling link exists between two SPs in order to provide redundancy. One signaling link can convey the signaling messages for many user circuits. The signaling points and the signaling links form an independent signaling network, which is overlaid over the circuit network.

Signaling modes Associated mode of signaling : the signaling link is routed together with the circuit group belonging to the link. In other words, the signaling link is directly connected to SPs which are also the terminal points of the circuit group. Quasi-associated mode of signaling, the signaling link and the circuit group run along different routes, the circuit group connecting the SP A directly with the SP B.

FUNCTIONAL LEVELS OF CCS#7

CCS#7 Functional levels Level 1 (signaling data link) defines the physical, electrical and functional characteristics of a signaling data link and the access units. Level 1 represents the bearer for a signaling link. Level 2 (signaling link) defines the functions and procedures for a correct exchange of user messages via a signaling link. error detection using check bits error correction by re-transmitting signal units error rate monitoring on the signaling data link restoration of fault-free operation,

CCS#7 Functional levels Level 3 (signaling network) defines the inter-working of the individual signaling Links. message handling, i.e. directing the messages to the desired signaling line, or to the correct UP signaling network management

Signal Units (SU) The MTP transports messages in the form of SUs of varying length. A SU is formed by the functions of level2. It also contains control information for the message exchange. There are three different types of SUs: Message Signal Units (MSU) Link Status Signal Units (LSSU) Fill-In Signal Units (FISU).

Advantages of CCS7 Signaling Signaling Channel is allotted only for the duration of the signaling (optimum utilization & space saving) Faster call setup Introduction of new services is possible More call completion Security of calls ensured Efficient NMS Easy & Efficient traffic engineering

CCS#7 NETWORK

Service Switching Points (SSPs) In conventional telephone networks, Service Switching Points (SSPs) are usually telephone central offices, also known as End-Offices, or Access Tandems. In the cellular mobile or wireless communications environment, an SSP is frequently located at the Mobile Switching Center (MSC).

Service Control Points (SCPs) Service Control Points (SCPs) are network intelligence centers where databases of call processing information are stored. The primary function of SCPs is to respond to queries from other SCPs, by retrieving the requested information from the appropriate database within the SCP node, and sending it back to the originator of the request.

Signaling Transfer Points (STPs) STPs like the EAGLE 5 ISS are ultra-reliable, high-speed packet switches at the heart of SS7 networks. They are nearly always deployed in mated pairs. The primary functions of STPs are to provide access to SS7 networks and routing of signaling messages.

STP Functions SS7 Message routing Global Title Translation SS7 Network Management Network Interconnection Gateway Screening

Message Routing All nodes in the network are identified by a unique point code. This point code is used by CCSS #7 as the Origination Point Code (OPC) and the Destination Point Code (DPC) in the routing label of all Message Signaling Units (MSUs). STPs have the ability to route messages to all types of signaling points.

Global Title Translation By using SCCP to translate addresses (Global titles) from signaling messages that do not contain explicit information allowing the MTP to route the message.

Network Management Acts as traffic cop to route traffic around failures in a network, and to control link congestion.

Gateway Screening Screening is the capability to examine Incoming and Outgoing packets and allow those which are authorized. This is done by going through a series of Gateway screening tables that must be configured by the service provider

Why SSTP is required in BSNL When any mobile subscriber roams to other Service Area then the signaling traffic or SMS are being handled by the signaling channel of BSNL taken by private operator against POI. BSNL is not able to measure the traffic and kind of traffic. By putting SSTP in system we can measure the traffic and bill to private operators. It will enable migration from TDM based network to IP based networks.

EAGLE 5 Integrated Signaling System EAGLE 5 ISS is a large-capacity, multi-functional, Signaling Transfer Point (STP). This system can grow from a single-shelf, 80-link STP to a multi-frame, 2000- link STP. The EAGLE 5 ISS does not have a separate central processing unit to bottleneck traffic throughput.

EAGLE 5 ISS Features Exceptional Capacity: The system supports up to 2,000 links, one million global title translation (GTT) table entries and 384 million subscriber records. High Performance: Transaction speeds of up to 640,000 message signaling units (MSUs) per second.

Features Flexible Interconnection: Supports multiple link interface types, including 100 Base-T, DS0A,, E1/T1 ATM HSL, channelized E1 and T1,and synchronous E1 HSL (SE-HSL). Network Security: Because signaling connectivity to other service providers is centralized at the EAGLE 5 ISS, gateway screening is centralized and not required at multiple switches.

IP Connectivity The EAGLE 5 ISS provides connectivity between SS7 and IP networks, enabling messages to pass between the SS7 network domain and the IP network domain.

EAGLE frames There are five types of EAGLE frames: Control Frames Extension Frames Miscellaneous Frames General Purpose Frames OAP Frame (not shown)

Control Frame (CF) Principal frame for system. Control shelf contains all components of Maintenance Administration Subsystem (MAS) Control shelf with up to ten application modules. Up to two extension shelves, each with up to 16 application modules.

Extension Frames Extension Frames (EF) Provisioned when more than two extension shelves are needed. Up to five per system (EF-00 to EF-04) Up to three extension shelves mounted in each frame (EF-04 has one extension shelf)

General Purpose Frame Integrated Sentinel- Sentinel Processor Frame ( SPF) Extended Services Platform (ESP) Sentinel Processor Frame (SPF) Multi Purpose Server. These frames are numbered GPF 00 through GFPxx

Miscellaneous Frame Optional frame May be equipped with a Fuse Alarm Panel (FAP) Equipment accommodated holdover clock: test equipment: jack panels: spare card shelf; printer; terminal; etc

Objectives of SSTP Regulate, measure, and account for inter-network traffic including SMS messages from mobile networks including GSM and CDMA Achieve flexibility and transparency in management of signalling for BSNL s wired and wireless networks. Optimal expansion of GSM & CDMA network of BSNL Introduction of new services. Offer CCS7 & IP Signaling Services to other Wire line & Wireless Network Operators.

SSTP s at BSNL Network 21 TAX Locations with an STP at each location. Pair of STPs are designated as mated pair with identical routing data and complete failover capability. Phase 1-10 Locations Phase 2-11 additional locations. 4 Additional locations are Jammu, Shimla, Dimapur, Shillong and dropping Raipur Phase 3 Expansion of all 24 nodes to about capacity of 1800 LSL per node

SSTP s at BSNL Network Connect multiple SS7 nodes (MSC, L1 TAX, L2 TAX, Local Exchanges, SMSC, HLR, SCP) to a mated pair Using SS7 E1 links. SSTPs interconnected using BSNL s IP/MPLS network on M2PA Later on M3UA functionality is also included to connect the access nodes e.g. Soft switch, GMSC, IN, HLR etc. Centralized Network Management with an Active and DR Standby site Central Billing Server for billing inter-carrier SS7 usage