Intelligent Network (IN) in Telecommunication Engineering
An Intelligent Network (IN) is a telecommunications network architecture that separates service logic
from the basic switching functions. This allows new services to be created, controlled, and modified
without making major changes to the telephone switching system.
1. Basic idea
In a traditional telephone network, much of the service intelligence is built directly into the switching
system. In an Intelligent Network, the switching equipment handles the basic call connection, while
specialized network elements provide additional service logic.
Simple architecture:
+----------------------+
|
Service Creation
|
|
Environment (SCE) |
+----------+-----------+
|
v
+----------------------+
| Service Control Point|
|
(SCP)
|
+----------+-----------+
|
SS7 / IN Signaling
|
+----------v-----------+
| Service Switching
|
| Point (SSP)
|
+----------+-----------+
|
v
Telephone Network
Basic IN Architecture
+----------------------+
|
Service Creation
|
| Environment (SCE)
|
+----------+-----------+
|
v
+----------------------+
| Service Management
|
| System (SMS)
|
+----------+-----------+
|
v
+----------------------+
| Service Control Point |
|
(SCP)
|
+----------+-----------+
|
SS7 / Signaling
|
v
+---------+
+----------------------+
| User
|<----------->| Service Switching
|
| / Phone |
Call
| Point (SSP)
|
+---------+
+----------+-----------+
|
v
+-------------+
| Telephone |
|
Network
|
+-------------+
+----------------------+
| Intelligent Peripheral|
|
(IP)
|
+----------------------+
Main components
Component
SSP – Service Switching
Point
Function
Detects calls requiring IN services and communicates with the
SCP.
Contains service logic and databases; determines how a service
SCP – Service Control Point
should be provided.
SMP – Service Management Used to manage service data, subscribers, and network
configuration.
Point
Provides tools for designing and developing new network
SCE – Service Creation
services.
Environment
Provides specialized resources such as announcements, voice
IP – Intelligent Peripheral
recognition, and DTMF collection.
Network Element
Name Functional Role
SSP
Service Switching Point The central or local telephone switch (or MSC in mobile networks)
equipped with IN software triggers. It detects IN calls, pauses basic call processing, and sends queries to
the SCP.
SCP
Service Control Point The central database and processing node containing the actual service
logic (e.g., toll-free routing algorithms, prepaid balance logic). It receives queries from the SSP and
returns execution instructions.
SDP
Service Data Point
A dedicated database engine containing real-time customer and
subscriber data (e.g., prepaid balance, calling restrictions).
IP
Intelligent Peripheral / Specialized Resource Function (SRF)
Handles specialized user
interactions such as playing voice announcements, recording audio, collecting DTMF digits, or
performing voice recognition.
SCE
Service Creation Environment Software tools used by network engineers to design, simulate,
and test new IN services before deployment.
SMS
Service Management System Centralized management plane that distributes new software
updates, monitors system health, and collects billing/CDR data.
How an IN call works
For example, consider a toll-free number:
1.
2.
3.
4.
5.
6.
A subscriber dials a toll-free number.
The SSP detects that the number requires an IN service.
The SSP sends a query to the SCP using signaling.
The SCP checks its database and determines the actual destination number.
The SCP sends the routing information back to the SSP.
The SSP establishes the call to the required destination.
Thus, the switching system does not need to contain all the service-specific logic.
4. Important IN services
Intelligent Networks can support services such as:










Freephone / toll-free service
Prepaid calling
Calling card service
Virtual Private Network (VPN)
Number translation
Automatic Call Distribution
Televoting
Call forwarding
Premium-rate services
Location-based services
5. Advantages of Intelligent Network



Rapid service development
Easy introduction of new services
Centralized service control




Reduced modification of switching systems
Flexible service management
Improved use of network resources
Supports customized subscriber services
6. IN and SS7
SS7 (Signaling System No. 7) is commonly used to provide the signaling communication
between IN elements, particularly between the SSP and SCP.
A simplified relationship is:
Subscriber
|
v
SSP
|
| SS7 signaling
v
SCP
|
v
Service Database
7. Key point for examinations
Intelligent Network (IN) is a telecommunications network architecture in which service
intelligence is separated from the basic call-switching function, allowing new services to be
developed and deployed rapidly through specialized network elements such as SSP, SCP,
and SMP.
In short:
SSP = detects and executes service-related call processing
SCP = provides service logic and decisions
SMP = manages service data and configuration
SCE = creates new services