For internal circulation of BSNL only

E1-E2 / E2-E3 CFA

SIGNALING IN TELECOM NETWORK

&

SSTP

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.

For internal circulation of BSNL only

TRUNK SIGNALING

Digital signaling

Channel Associated signaling (CAS)

Common Channel Signaling (CCS)

For internal circulation of BSNL only

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.

For internal circulation of BSNL only

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.

For internal circulation of BSNL only

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

For internal circulation of BSNL only

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.

For internal circulation of BSNL only

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.

For internal circulation of BSNL only

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.

For internal circulation of BSNL only

FUNCTIONAL LEVELS OF CCS#7

For internal circulation of BSNL only

CCS#7 Functional levels

For internal circulation of BSNL only

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

For internal circulation of BSNL only

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).

For internal circulation of BSNL only

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

For internal circulation of BSNL only

CCS#7 NETWORK

For internal circulation of BSNL only

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).

For internal circulation of BSNL only

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.

For internal circulation of BSNL only

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.

For internal circulation of BSNL only

STP Functions

SS7 Message routing

Global Title Translation

SS7 Network Management

Network Interconnection

Gateway Screening

For internal circulation of BSNL only

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.For internal circulation of BSNL only

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.

For internal circulation of BSNL only

Network Management

Acts as traffic cop to route traffic around failures in

a network, and to control link congestion.

For internal circulation of BSNL only

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

For internal circulation of BSNL only

For internal circulation of BSNL only

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.

For internal circulation of BSNL only

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.

For internal circulation of BSNL only

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.

For internal circulation of BSNL only

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.

For internal circulation of BSNL only

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.

For internal circulation of BSNL only

EAGLE frames

There are five types of EAGLE frames:

Control Frames

Extension Frames

Miscellaneous Frames

General Purpose Frames

OAP Frame (not shown)

For internal circulation of BSNL only

For internal circulation of BSNL only

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.

For internal circulation of BSNL only

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)

For internal circulation of BSNL only

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 GFP-

xx

For internal circulation of BSNL only

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

For internal circulation of BSNL only

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 BSNLs 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.

For internal circulation of BSNL only

SSTPs 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

For internal circulation of BSNL only

SSTPs 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 BSNLs 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

For internal circulation of BSNL only

For internal circulation of BSNL only