transport networks signaling isdn

8/17/2019 Transport Networks Signaling ISDN

1/27


2/27

Signaling NetworkIt consists of a set of reserved or dedicated channels known as signaling links


3/27

Service Switching Points (SSPs) originate or

terminate a call and communicate on the signalling

network with Service Control Points (SCPs) to

determine how to route a call or set up and managesome special feature.

Traffic on the signaling network is routed by packet

switches called Signal Transfer Points (STPs).

SCPs and STPs continuously communicate with each

other to ensure that service can continue if one

network point fails.


4/27

Intelligent Network (IN)

• An enhanced signalling network

• Provides an array of services (e.g., caller ID,

personal ID enabling mobility, call back, …)

• Except the basic switching functions, all othersignalling operations are shifted to SCP (Service

Control Points) in the signalling network.

• Allows introduction of new services withoutchanging the hardware/software of switching

vendors.


5/27

Intelligent Network (IN)


6/27

Signaling System #7

Architecture


7/27

SS7 uses out-of-band signaling,which means that signaling (control)

information travels on a separate,

dedicated 56 or 64 Kbps channelrather than within the same channel

as the telephone call.


8/27

ISDN(Integrated Services Digital Network)


9/27

ISDN

• a switched digital telecommunication line

that can be delivered over regular copper

wires

• provides end-to-end digital

communications

• Can be obtained from a local telephone

company in the same way an analog

connection is obtained


10/27

ISDN

• There are two different types of ISDN

services that are widely available

• Basic Rate Interface (BRI)

– Used for home or SOHO (small office/Home

Office) connection

• Primary Rate Interface (PRI)

– Used in large businesses


11/27

Evolution of ISDN


12/27

Voice over Analog Network


13/27

Voice and Data over Analog Network


14/27

Analog and Digital Services


15/27

Integrated Digital Network


16/27

Integrated Services Digital Network


17/27

Basic Rate Interface


18/27

Primary Rate Interface


19/27

Functional Grouping


20/27

Figure 15-10

Reference Points


21/27

ISDN specifies a number of reference points that define

logical interfaces between functional groups, such as TAsand NT1s.

R - The reference point between non-ISDN equipment and

a TA.S - The reference point between user terminals and the

NT2.

T - The reference point between NT1 and NT2 devices.

U - The reference point between NT1 devices and line-

termination equipment in the carrier network.


22/27

ISDN terminals come in two types:

1. Specialized ISDN terminals are referred to as terminalequipment type 1 (TE1).

2. Non-ISDN terminals, such as DTE, that predate the ISDN

standards are referred to as terminal equipment type 2

(TE2).

TE1s connect to the ISDN network through a four-wire,

twisted-pair digital link. TE2s connect to the ISDN network

through a TA. The ISDN TA can be either a standalone

device or a board inside the TE2.


23/27

Beyond the TE1 and TE2 devices, the next connection

point in the ISDN network is the network termination type 1

(NT1) or network termination type 2 (NT2) device. These

are network-termination devices that connect the four-wiresubscriber wiring to the conventional two-wire local loop.

In North America, the NT1 is a customer premises

equipment (CPE) device. In most other parts of the world,

the NT1 is part of the network provided by the carrier.

The NT2 is a more complicated device that typically is

found in digital private branch exchanges (PBXs) and that

performs Layer 2 and 3 protocol functions andconcentration services.

An NT1/2 device also exists as a single device that

combines the functions of an NT1 and an NT2.


24/27

BRI Interfaces


25/27

PRI Interfaces


26/27

B-ISDN would be able to provide end users with increasedtransmission rate,up to 155.54Mbits/s on a switching basis.

… is to offer subscribers a large variety of services such as

video telephony, video surveillance, high volume file

transfer, High Definition Television(HDTV) and many more

services not offered by ISDN.

.. is designed to use ATM technology over fiber optic

cables.

Broadband Integrated Services Digital Network

(B-ISDN)


27/27

transport networks signaling isdn

Documents