ET2080 JARINGAN TELEKOMUNIKASI

ET2080 JARINGAN TELEKOMUNIKASI

Tutun Juhana – Program Studi Teknik Telekomunikasi

STEI - ITB

Signaling

Definition The IEEE defines signaling as the

exchange of information specifically concerned with the establishment and control of connections and the transfer of user-to-user and management information in a telecommunication network

Conventional signaling has evolved with the telephone network

ET2080 Jaringan Telekomunikasi

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With telephony, signaling is broken down in three functional areas: Supervisory Address Call progress: audible-visual

Another signaling breakdown is Subscriber signaling Interswitch (interregister) signaling


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Supervisory Signaling Supervisory signaling provides

information on line or circuit condition It informs a switch whether a circuit

(internal to the switch) or a trunk (external to the switch) is busy or idle, when a called party is off-hook or on-hook, and when a calling party is on-hook or off-hook


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Address Signaling Address signaling directs and routes a telephone

call to the called subscriber It originates as dialed digits or activated push-

buttons from a calling subscriber The local switch accepts these digits and, by

using the information contained in the digits, directs the call to the called subscriber

If more than one switch is involved in the call setup, signaling is required between switches (both address and supervisory)

Address signaling between switches is called interregister signaling


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Call Progress: Audible-Visual This type of signaling we categorize in

the forward direction and in the backward direction

In the forward direction there is alerting This provides some sort of audible-visual

means of informing the called subscriber that there is a telephone call waiting

This is often done by ringing a telephone’s bell

A buzzer, chime, or light may also be used for alerting.ET2080 Jaringan Telekomunikasi

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In the backward direction, among these are audible tones or voice announcements that will inform the calling subscriber the following: Ringback

This tells the calling subscriber that the distant telephone is ringing.

Busyback This tells the calling subscriber that the called line is busy

ATB-All Trunks Busy There is congestion on the routing. Sometimes a recorded

voice announcement is used here. Loud Warble on Telephone Instrument—Timeout This occurs when a telephone instrument has been left

off-hook unintentionally


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Signalling

Subscriber - exchange Exchange - exchange

Channel associated Common channel

Klasifikasi Signaling8


Areas of Signaling There are mainly three areas of signaling during a

telephone call : between subscribers and exchanges. within exchanges. between exchanges.


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Exchange A Exchange B

between Subscriber

and exchange

within exchange

between exchange

s

Subscriber – Exchange Signaling

• Dari pelanggan ke sentral– Informasi kondisi off-hook– Informasi nomor B (nomor tujuan)– Informasi jumlah uang yang dimasukkan (khusus untuk

payphone)– Informasi kondisi on-hook ketika panggilan usai

• Dari sentral ke pelanggan A (nomor pemanggil)– Informasi bahwa sentral siap menerima nomor B– Informasi mengenai status B (busy atau tidak)– Informasi kongesti atau interception– Sinyal charging (khusus untuk payphone)

• Dari sentral ke pelanggan B– Sinyal ringing untuk menarik perhatian pelanggan B

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• Pelanggan A mengangkat telepon, hal ini dapat berarti– A ingin menghubungi seseorang– Pesawat A berbunyi lalu menjawab

• Sentral dapat mendeteksi keadaan telepon apakah merupakan panggilan atau jawaban

• Sentral menanggapi panggilan dengan mengirimkan dial tone

• A mengirimkan digit nomor B (B number)

• Sentral menganalisa digit lalu mencek apakah B ada dan tidak busy. Ringing tone dikirimkan ke A sedangkan sinyal ringing ke B

• B mengangkat handset, sentral mendeteksinya sebagai jawaban

• Ketika A dan B menyimpan handset, sentral mendeteksi sebagai sinyal clear lalu koneksi diputuskan

Bsentral

Off-hook

Dialling tone

conversation

A

NOMOR

Ringing tone Ringing signal

~425Hz ~90V, 20-25 Hz

answer

Clear forwardClear back


Off-Hook Signaling (Analog) Loop Start (almost all telephones)

Seizure is detected when current flows through local loop, due to off-hook

Ground Start (antar PBX (Private Branch Exchange) atau antara PBX dengan Sentral Lokal) Seizure (upaya pendudukan kanal komunikasi) is detected when

one wire is grounded Seizure can be initiated in both directions Untuk mengindikasikan status on/off-hook ke sentral lokal

Ground Start

Source: Cisco Interactive Mentor12 ET2080 Jaringan Telekomunikasi

Switch Switch

Loop Start Ground Start


Exchange – exchange Signaling Channel Associated Signalling (CAS) Common Channel Signalling (CCS)

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Channel Associated Signaling

Signaling dilakukan menggunakan kanal yang juga digunakan untuk mentransfer informasi

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Channel Asociated Signalling

• Informasi speech dan informasi signalling mengalir melalui jalur yang sama

• Beberapa macam CAS– Signalling dilakukan secara bersama pada

kanal untuk speech (DC signalling, inband)– Signalling dilakukan pada kanal yang sama

dengan speech tetapi menggunakan frekuensi yang berbeda (out-band)

• Contoh: Signalling dilakukan melalui timeslot 16 (PCM signalling)


Seizure acknowledgment

Pelanggan A Pelanggan B

sentral sentral

seizure

B number

answer

conversation

Clear forward

Clear back B- hangs up

A- hangs up


Forward and Reverse direction Forward signal mengalir dari sentral

telepon tempat A berada menuju sentral telepon tempat B berada

Backward signal mengalir pada arah yang berlawanan dengan forward signal

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Common Channel Signaling

Signaling menggunakan kanal yang terpisahdari kanal untuk mentransfer informasi Terdapatjaringan signaling tersendiri

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Signaling System Number 7 (SS #7)

Signaling System NO. 720


Signaling System No. 7 (SS No. 7) was developed to meet the stringent signaling requirements of the all-digital network based on the 64-kbps channel

It is a data network entirely dedicated to interswitch signaling


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SS No. 7 is described as an international standardized general-purpose common-channel signaling system that: Is optimized for operation with digital networks

where switches used stored-program control (SPC)

Can meet present and future requirements of information transfer for interprocessor transactions with digital communications networks for call control, remote control, network database access and management, and maintenance signaling

Provides a reliable means of information transfer in correct sequence without loss or duplication


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CCS7 Network Components

The CCS7 Network consists of the following Components : SP -Signaling Point : The SP is the source or

originating entity of the signaling message. STP-Signaling Transit Point : These entities

transfer the signaling message to another SP or STP without processing the signaling message.

SRP – Signaling Relay Point : These are STPs with ability tp process the signaling message.

SEP – Signaling End Point : The SEP is defined to be the terminating point of the signaling message

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CCS7 Network Architecture A typical SS7 network is a mixture of various SPs STPs SRPs

and SEPs, As shown below :

SP (SPC=100)

SRP (SPC=400)

STP (SPC=300)

STP (SPC=200)

SEP (SPC=500)

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CCS7 Terminologies SPC : SPC is defined as signaling point code which

uniquely identifies each element within the SS7 network.

Signaling Links : The signaling links transmit signaling messages between the communicating entities.

Signaling Link Set : A signaling link set is a collection of signaling links between two signaling entities.

Signaling Route : A signaling route is defined to be the path through which signaling messages are exchanged between two entities. There can be multiple signaling routes between two SPCs, wherein there will be one primary route and several alternate routes.

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SS7 Routing Modes Associated Mode :

In the associated mode, the signaling link is routed together with the circuit group belonging to the link. In other words, the signaling link is directly connected to signaling points which are also the terminal points of the circuit group. This mode of signaling is recommended when the capacity of the traffic relation between the signaling points A and B is heavily utilized.

Associated Mode of Signaling

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SS7 Routing Modes Quasi associated mode :

In the quasi-associated mode of signaling, the signaling link and the circuit group run along different routes, the circuit group connecting the signaling point. A is directly connected with the signaling point B. For this mode the signaling, the circuit group is carried out via one or more defined signaling transfer points. This signaling mode is favorable for traffic relations with low capacity utilization, as the various signaling links can be used for several destinations.

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SS7 Network Structure

SPC=100

SPC=200

SPC=300

SPC=100

SPC=400

SPC=500

SPC=600

SPC=400

SPC=900 SPC=800

SPC=700

SPC=800

SPC=100

SPC=100

SPC=300

SPC=200

INAT 0

NAT 0

NAT 1

NAT 1 NAT 1

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SS7 Protocol Structure SS7 protocol stack can be broadly divided into two main

categories :

A ) MTP – Message Transfer Part : The message transfer part has three levels , namely MTP Layer 1, Layer 2 and Layer 3. The message transfer part (MTP) represents a user-neutral means of transport for messages between the users.

B ) User Parts (UP) : Each user part (UP) encompasses the functions, protocols and coding for the signaling via SS7 for a specific user type (e.g. data service, ISDN). In this way, the user parts control the set-up and release of circuit connections, the processing of facilities as well as administration and maintenance functions for the circuits.

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SS7 Protocol Structure

MTP Layer 3 (Network Management)

MTP Layer 1 (Signaling Data Link)

MTP Layer 2 (Signaling Link)

SCCP

BSSAP

ISUPTCAP

TCAP Users

SS7 Users

MUP

Other User Parts


Contoh signaling CCS#7IAM: Paket pertama yang membawa informasi nomor BSisa nomor berikutnya dibawa oleh SAM

ACM: Paket yang berisi konfirmasi dari sentral B bahwa seluruh digit sudah diterima; selain itu paket ini berisi pula informasi apakah panggilan dapat di-charge atau tidak juga apakah pelanggan tujuan sibuk atau tidak

Ketika pelanggan B off-hook, sentral B mengirimkansinyal ACN untuk mengaktifkan charging


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ET2080 JARINGAN TELEKOMUNIKASI