Government Engineering College, Bharuch

Telecommunication Switching Systems And Network presentation

Signaling TechniquesSignaling TechniquesBasics of CCSBasics of CCS

Prepared by :

Xyz

6th Sem (E.C-A)

Signaling Definition

It is the dialog language for the communication between various parts of the telecom network.

Working area

•Subscriber signaling: Between sub. & switch

•inter-office: Control the setup and release of call

Signaling function

Monitoring signals: Monitor the changes of call states or conditions in the lines

•Selection signals ： Routing information

•Operation signals: Management and maintenance of telecom networks

Signaling Classification

Transmitting path

1.Channel Associated Signaling

2.Common Channel Signaling

Common Channel Signaling (CCS)

In telephony, Common Channel Signaling (CCS), is the transmission of signaling information (control information) on a separate channel from the data, and, more specifically, where that signaling channel controls multiple data channels.

Channel Associated Signaling (CAS)

Channel Associated Signaling (CAS), also known as per-trunk signaling (PTS), is a form of digital communication signaling. As with most telecommunication signaling methods, it uses routing information to direct the payload of voice or data to its destination. With CAS signaling, this routing information is encoded and transmitted in the same channel as the payload itself.

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Channel Associated Signaling

Advantages of CCS

Compared with Channel Associated Signaling, Common Channel Signaling has many important advantages

• Information can be switched between processors much faster than in channel-associated signaling.

• With a huge signal capacity, it can hold dozens or even hundreds of different kinds of signals, thus providing more new services.

• With a great flexibility, it can provide more new services simply by modifying software to increase signals.

• Line signaling device is not needed any more at any trunk station, which shall greatly reduce investment costs.

• Since line signaling is no longer needed, trunk devices can be used both in calls from A to B, and in calls from B to A.

• In such bi-directional working modes, even less circuits are required than when trunk circuits are respectively used in single call directions.

• When a call is being set up, signals related to this call can be sent. In this way, the subscriber can change the already setup connections. For example, the subscriber can transfer one call to another place, or request a third party to join the present connections.

• Signals can be switched between processors so as to be used for maintenance or network management.

• Signaling can provide powerful support for ISDN, IN, TMN (telecommunication management Network) and cellular mobile communication systems, as this signaling is their basis.

Disadvantages of CCS

• The error rate of the common channel signaling system must be very low.

• Its reliability must be much higher than the channel associated signaling system. This is because once the data link fails, all related calls between the two related switches shall be affected.

Common Channel Signaling Network

The CCS network consists of the following parts • Signaling point (SP)

It refers to the node in the signaling system that provides Common Channel Signaling. SP can also be divided into source points – OPC (Originating Point Code)

The SP that generate signaling messages– DPC (Destination Point Code)

The SP that receives signaling point code.

Thank You