2a. circuit switching - signaling

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CIRCUIT SWITCHING -SIGNALING

Introduction

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Introduction

Introduction

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Introduction

Introduction

Residential customer

Business customer

Residential customer

Business customer

Class 1: regional centers

Class 2: sectional centers

Class 3: primary centers

Class 4: toll centers

Class 5: local central office

Local loops

Tandem office

Local loops

Local Carrier's Domain of Influence, Intra-LATA

Class 1: regional centers

Class 2: sectional centers

Class 3: primary centers

Class 4: toll centers

Class 5: local central office

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Introduction

LATA – Local Access and Transport AreaIC – Interexchange Carrier

Introduction

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Numbering Plan

Numbering Plan - Example

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Numbering Plan - Example

Signaling

Intra-exchange signaling (Subscriber Signaling)

Inter-exchange signaling (Signaling between exchange)

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Subscriber signaling

Subscriber Signaling

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Subscriber SignalingLine Signaling

Subscriber SignalingLine Signaling

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Subscriber SignalingAddress Signaling

Subscriber SignalingAddress Signaling

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Subscriber SignalingRinging Signaling

Subscriber SignalingTones and Announcements

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Subscriber SignalingTones and Announcements for Supplementary services

Supplementary services

Customer Calling Services

Customer Local Area Signaling Services (CLASS)


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Inter-Exchange Signaling

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Inter-Exchange signaling

Channel-Associated inter-exchange Signaling (CAS) – per trunk signaling

Common Channel Signaling (CCS)


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Inter-Exchange SignalingChannel-Associated Signaling (CAS)


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Channel-Associated Signaling systems:

Bell System multi-frequency (MF) signaling

CCITT No. 5 signaling

R2 signaling

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Inter-Exchange SignalingChannel-Associated Signaling (CAS) – R2/MFC

R2 signaling Known as multi-frequency compelled (MFC), MFC-R2 or

R2 signaling system

Can be used on 2-wire analog trunks; 4-wire analog and digital trunks

Can not be used on TASI-equiped trunks and trunks carried by satellite transmission systems -->Application of R2 is limited to relative short international trunks

Most important difference between R2 and Bell MFC & CCITT No.5 is its register (address) signaling


Supervision signaling on digital trunks

Network (national/international R2 signaling) use E1 for digital trunks

Super-frame consists of 16 consecutive frames, numbered from 0 to 15

For super-frame alignment, bit 1 – 4 in TS16 of frame 0 are coded 0000

TS16 in frame 1 to 15 carries 4 status bits for the trunks

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Supervision signaling on digital trunks

Supervision signaling for digital international R2 trunks is continuous

2 forward and 3 backward trunk states, represented by bit af, bf and ab, bb

respectively

Bit c & d are not used and set to 0 and 1


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Inter-Exchange SignalingCommon Channel Signaling (CCS)

Common channel signaling, introduced in 1976, was developed as an alternative form of call-control signaling for trunks.

In CCS, signaling information is not carried by the individual trunks

Signaling network transfer signaling messages between exchange

Signaling network consist of: Signaling Data Link (SDL)

Signaling Transfer Point (STP)

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Service Control Point (CSP) and an Operation, Administration & Maintenance (OAM) center also have signaling data links

Exchanges can send messages to, and receive messages, from these entities

Procedures that involve signaling between an exchange and a SCP, or between an exchange and a OAM center, are known as transactions

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An SCPs in a network support Intelligent Network (IN). These services require information that can not be store in a

exchange conveniently

The OAM centers allow centralized operation, administration and maintenance of the network, example Transaction in which OAM center requests an exchange to

test a particular trunk to report the test results

Transactions enable the OAM centers to verify and change subscriber and routing data that stored in the exchanges.


1st generation of CCS was introduced in 1970s Common Channel Interoffice Signaling (CCIS), defined by

Bell System

Signaling system No. 6, defined by CCITT

2nd generation: Signaling System 7 (SS7)

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Inter-Exchange SignalingCommon Channel Signaling (CCS) – SS7

SS7 Hierarchy Organized in 4-level Hierarchy

OSI Model Signalling System 7 Description/Function

Application

Presentation

Session

Transport

Network

Datalink

Physical

Operations Maintenance Application Part (O&MAP)

Transaction Capabilities Application Part (TCAP)

Network Service Part (NSP)

Signalling Connection Control Part (SCCP)

Message Transfer Part (MTP)

O&MAP provides standards for routing and management of messages related to network operations and maintenance

TCAP provides standards for routing and management of noncircuit related information for transaction processing applications requiring out-of-band signalling

Another term for the combination of the SCCP and the MTP3

SCCP provides standards for routing and management of signalling messages. Not related to call set-up between switches. A connection-oriented service providing reliable message delivery

MTP provides standards for routing of signalling messages between switches. A connectionless, datagram service

Protocol Name

O&MAP

TCAP

SSCP

MTP


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Inter-Exchange SignalingCommon channel Signaling – SS7

Message Transfer Part (MTP) – this protocol provides message transfer services for its user Divided into 3 parts: MTP1, MTP2, MTP3, that occupy level

1, 2 and 3 of SS7 hierarchy

A MTP user passes its outgoing messages to – and receives its incoming messages from – the MTP3 at its signaling point

A signaling has one MTP3

A combination of MTP1 & 2 represents a signaling link at a signaling point

A signaling point that terminates n signaling links has n of these combinations

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Telephone User Part (TUP) MTP user

Protocol for telephony call control and for trunk maintenance

Integrated Service User Part (ISUP) MTP user

Protocol for call control and trunk maintenance procedures in both the telephone network and the ISDN

Signaling Connection Control Part (SCCP) MTP user

Provide functions for the transfer of messages that are not trunk-related

Its users are ISUP and TCAP


Transaction Capability Application Part (TCAP) Transactions are operation that are not related to individual

trunks and involve 2 signaling point

TCAP protocol provides standard interface to TC-user (functions at signaling point)

TCAP is a user of SCCP

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2a. circuit switching - signaling

Documents

regional centersclass

cas r2mfc r2

toll centersclass

sectional centersclass

primary centersclass

application of r2

wire analog trunks

cas channel