This is a depiction on Legacy Telecom technologies and landscape. It describes the outdated approach in Telecom network and their new updates technology versions for IP based Telecom networks .

1. TELECOM LEGACY SYSTEM
-Altanai Bisht
-tara181989@gmail.com
-http://altanaitelecom.wordpress.com

2. Legacy Landscape
2
Transmission
• ATM/Frame relays primarily constitutes the legacy.
• Moving towards IP/MPLS.
Access
• Transformation from hardware specific POTS / PSTN / ISDN
towards NGN and VOIP.
Core
• Packet Switched NGN Soft Switches.
• Reduced cost of SIP Trunks over ISDN trunks.
Service Delivery
• Harmonized and uniform open standard based service delivery
platforms over legacy Proprietary SDKs

3. 3
Domain Elements Characteristics Transformation
Path
Transmission ATM / Frame Relay -Hardware Specific
-High Expenses
-IP
-MPLS
Access POTS / PSTN / ISDN
-Hardware Specific
-High Expenses
-Low stability
-NGN
-VOIP
Core Traditional Switches /
ISDN
-High OPEX/CAPEX
-Soft switch
-SIP Trunking
Service Delivery Traditional IN switches -Hardware Centric -Based on Open
Standards

4. 4
Current Telco networks Closed Telco NGN
networks - Closed
Internet – open
Circuit switched technology ATM/IP based technology IP based technology
Intelligent network Less intelligent network Dumb network
Dumb terminal More intelligent terminal Intelligent terminal
User-user services centrally
controlled by provider of
transport service
User-user services centrally
controlled, with much greater
scope for third party services.
.
• User-user services run by
users
themselves. No service
creation -
services and applications run
from edge.
Interconnection is service
related
and controlled
Interconnection may occur at
various levels. Above the IP
level it is likely to be service
related and controlled.
Interconnection is open and
only
at IP level.
Few/no third party services Few/no third party services Numerous third party
services

5. 5
Soft Switch
Legacy Switch NGN Soft Switch
•Circuit Switched
•Monolithic
•Proprietary
•Expensive
•Dependant
•Packet Switched
•Distributed
•Open Interfaces
•Scalable
•Vendor independent
•Convergence
Benefits of NGN Soft Switches over Legacy Switches
• Increase the granularity and power processing distribution of the Network
–Low density interconnection
–Signalling, Media and IN capabilities distributed or concentrated depending on carrier needs
• One Network
–Reduction planning and engineering time
–Reduction maintenance and operation costs
• Transport
–Eliminate the need of internal E1
–Reduction bandwidth needed
–Reduction maintenance and operation costs

6. Centralize and eliminate redundant connections. Buy exact number
of connections needed
(no need to buy in increments of 24)Idle connections at one location
to be used for calls at other locations. SIP Trunking services
typically allow ports to be added or deleted quickly.
6
Trunking
ISDN PRI SIP Trunking
Usage costs On a comparable basis, ISDN PRI service can be 2x the
cost of SIP Trunking service.
Around two times less costly.
T-1 and ISDN PRI access arrangements require that
trunks be purchased in bunches of 23 or 24. For each T-
1 or ISDN PRI access connection, the customer has to
rent a 1.544 Mbps dedicated line to the carrier’s serving
point.
Free features Features like call transfer may cost $50 per trunk per
month, making a SIP option far more advantageous.
SIP Trunking services often include services that charged for on
ISDN PRI or T-1 services
Organizations spend considerable time and effort
processing and auditing telephone bills, tracking usage,
and setting up internal chargebacks.
Bundling options make it easy to get started and simplify monthly
invoice review
•Per User – Local and long distance service can be priced at a flat
rate per user
•Per Port – Priced like a flat-rate SIP port that is shared by a
number of users
Benefits of SIP Trunking over ISDN Trunking
Aggregation of trunks and
access
Simplified billing and
administration
• Reduce Usage Costs: Upto 30% cost reduction through multi-modal communication capabilities of SIP Trunking
enables.
• Trunk Aggregation: Centralize and eliminate redundant connections. Idle connections at one location to be used for
calls at other locations which gives increased flexibility over traditional T1 PRI.
• Flexibility: Gives the flexibility to expand or contract the capacity of no. of connections required.
• Improved quality: Keeps the communications on pure IP connections vs. T1 PRI connection, improving voice and
video quality and preserving features like HD audio.
• Simplified Billing: Make it easy to get started and simplify monthly invoice review.

7. Legacy Service Layer NGN Service Layer
Key Highlights of NGN Service Layer
•SDP playing as a Broker.
•SOA and Open APIs pave the way to open and decentralized (distributed) SDPs.
•SDP offered as the service of the cloud(SDPaaS).
•Data enhanced SDP (e.g. via data mining capabilities).
•Moving towards software centricity and low cost based SDPs.
•Service Orchestration with Internet and legacy.
•Fast and agile development and deployment of convergent services.
•IMS providing the framework for underline network agnosticism across fixed and mobile.
•Resource brokering for mediation.
•RESTful interface and web application based integration.
7
Service Delivery Layer
•Existence of multiple domain
specific SDPs(Mobile, IPTV
and legacy broadband
services etc.)
• Function centric architecture
•Proprietary SDKs
•Legacy service delivery
Inefficient an expensive.
•Harmonized and uniform service
delivery layer.
•Open APIs for 3rd parties and
social features.
•Data Centric service architecture
•Standard interface defined
SDKs.
•Strategic differentiator for
telecom providers through Multi-party
business models for
innovative services.
Back
Office
Applicati
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Service
Delivery
Session
Control
Transmissi
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Termin
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Back Office
Applica
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Service
Delivery
Session
Control
Transmi
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Termi
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